Trane SCWG-020, SCWG-025, SCWG-030, SCWG-032, SCWG-035 Installation and Maintenance Manual

Installation, Operation,
and Maintenance

Intellipak™
Commercial Self-Contained

Modular Series
20 to 35Tons

Models

Only qualified personnel should install and service the equipment.The installation, starting up, and servicing
of heating, ventilating, and air-conditioning equipment can be hazardous and requires specific knowledge and
training. Improperly installed, adjusted or altered equipment by an unqualified person could result in death or
serious injury.When working on the equipment, observe all precautions in the literature and on the tags,
stickers, and labels that are attached to the equipment.

June 2014

SCWG -020, -025, -030, -032, -035
SIWG -020, -025, -030, -032, -035
SCRG -020, -025, -032
SIRG -020, -025, -032

SAFETY WARNING

SCXG-SVX01H-EN

Introduction

Read this manual thoroughlybefore operating or servicing
this unit.

Warnings, Cautions, and Notices

Safety advisories appear throughout this manual as
required.Your personal safety and the proper operation of
this machine depend upon the strict observance of these
precautions.

The three types of advisories are defined as follows:

WARNING

CAUTIONs

NOTICE

Important Environmental Concerns

Scientific research has shown that certain man-made
chemicals can affect the earth’s naturally occurring
stratospheric ozone layer when released to the
atmosphere. In particular, several of the identified
chemicals that may affect the ozone layer are refrigerants
that contain Chlorine, Fluorine and Carbon (CFCs) and
those containing Hydrogen, Chlorine, Fluorine and
Carbon (HCFCs). Not all refrigerants containing these
compounds have the same potential impact to the
environment.Trane advocates the responsible handling of
all refrigerants-including industry replacements for CFCs
such as HCFCs and HFCs.

Important Responsible Refrigerant Practices

Trane believes that responsible refrigerant practices are

important to the environment, our customers, and the air
conditioning industry. All technicians who handle
refrigerants must be certified.The Federal Clean Air Act
(Section 608) sets forth the requirements for handling,
reclaiming, recovering and recycling of certain
refrigerants and the equipment that is used in these
service procedures. In addition, some states or
municipalities may have additional requirements that
must also be adhered to for responsible management of
refrigerants. Know the applicable laws and follow them.

Indicates a potentially hazardous
situation which, if not avoided, could
result in death or serious injury.

Indicates a potentially hazardous
situation which, if not avoided, could
result in minor or moderate injury. It
could also be used to alert against
unsafe practices.

Indicates a situationthat could resultin
equipment or property-damage only
accidents.

WARNING

Refrigerant under High Pressure!

System contains oil and refrigerant under high
pressure. Recover refrigerant to relieve pressure before
opening the system. See unit nameplate for refrigerant
type. Do not use non-approved refrigerants, refrigerant
substitutes, or refrigerant additives. Failure to recover
refrigerant to relieve pressure or the use of non­approved refrigerants, refrigerant substitutes, or
refrigerant additives could result in an explosion which
could result in death or serious injury or equipment
damage.

WARNING

Personal Protective Equipment (PPE)
Required!

Installing/servicing this unit could result in exposure to
electrical, mechanical and chemical hazards.

• Before installing/servicing this unit, technicians
MUST put on all PPE required for the work being
undertaken (Examples; cut resistant gloves/sleeves,
butyl gloves, safety glasses, hard hat/bump cap, fall
protection, electrical PPE and arc flash clothing).

ALWAYS refer to appropriate Material Safety Data

Sheets (MSDS)/Safety Data Sheets (SDS) and OSHA
guidelines for proper PPE.

• When working with or around hazardous chemicals,

ALWAYS refer to the appropriate MSDS/SDS and

OSHA/GHS (Global Harmonized System of
Classification and Labelling of Chemicals) guidelines
for information on allowable personal exposure
levels, proper respiratory protection and handling
instructions.

• If there is a risk of energized electrical contact, arc, or
flash, technicians MUST put on all PPE in accordance
with OSHA, NFPA 70E, or other country-specific
requirements for arc flash protection, PRIOR to
servicing the unit. NEVER PERFORM ANY
SWITCHING, DISCONNECTING, OR VOLTAGE

TESTING WITHOUT PROPER ELECTRICAL PPE AND
ARC FLASH CLOTHING. ENSURE ELECTRICAL

METERS AND EQUIPMENT ARE PROPERLY RATED
FOR INTENDED VOLTAGE.

Failure to follow instructions could result in death or
serious injury.

© 2014 Trane All rights reserved SCXG-SVX01H-EN

WARNING

Proper Field Wiring and Grounding
Required!

Failure to follow code could result in death or serious
injury. All field wiring MUST be performed by qualified
personnel. Improperly installed and grounded field
wiring poses FIRE and ELECTROCUTION hazards.To
avoid these hazards, you MUST follow requirements for
field wiring installation and grounding as described in
NEC and your local/state electrical codes.

NOTICE:

Use Copper Conductors Only!

Unit terminals are not designed to accept other types
of conductors. Failure to use copper conductors could
result in equipment damage.

Copyright

This document andthe information in it arethe property of
Trane, and may not be used or reproduced in whole or in

part without written permission.Trane reserves the right
to revise this publication at any time, and to make changes
to its content without obligation to notify any person of
such revision or change.

Introduction

Trademarks

Trane, Intellipak,Tracer and theTrane logo are trademarks

ofTrane in the United States and other countries.All
trademarks referenced in this document are the
trademarks of their respective owners.

Revision History

SCXG-SVX01H-EN (24 Jun 2014)

Updated to correct input line current for 575V, 15HP, with
bypass.

SCXG-SVX01G-EN (23 Oct 2012)

Updated fan motor FLA data.

SCXG-SVX01H-EN 3

Table of Contents

Model Number Descriptions .............. 6

Modular Series Self-Contained .......... 6

Self-Contained Ship-With Accessory Model
Number

.............................. 8

Remote Air-Cooled Condenser .......... 8

General Data ............................ 9

Modular Series Self-Contained Unit
Components

.......................... 9

General Data ......................... 11

Pre-Installation Considerations ........... 13

Receiving ............................ 13

Contractor Installation Responsibilities .. 13

Unpackaging ......................... 13

Dimensions & Weights .................. 16

Service Clearances .................... 24

Installation - Mechanical ................ 25

Unit Handling Procedures ............. 25

Skid Removal ...................... 27

Installation Preparation ................ 27

Split-Apart Unit Assembly ............ 28

Unit Vibration Isolator Option .......... 29

Duct Connections ..................... 30

Plenum .............................. 30

Airside Economizer Installation ......... 31

Water Piping ......................... 32

Condenser Connections .............. 32

Condensate Drain Connections ........ 32

General Waterside Recommendations:

Cooling Towers .................... 32

Waterside Piping Arrangements ....... 33

Water Temperature Requirements ..... 33

Waterside Economizer Installation
Procedure

Waterside Economizer with right-hand

factory piping components ........... 35

........................... 34

Hydronic Coil Installation .............. 36

Refrigerant System ................... 36

Interconnecting Piping ............... 37

Preliminary Refrigerant Charging ....... 37

Installation - Electrical ....................39

Unit Wiring Diagrams ..................39

Supply Power Wiring ..................39

Selection Procedures ..................40

Variable Frequency Drive Option (VFD) ...41

Variable Frequency Drive Without ByPass 41

Variable Frequency Drive With ByPass . .45

Static Pressure Transducer Installation
(VAV units only)

.......................49

Electric Heat Installation ................49

Standard with All IntelliPak Units .......51

Zone Sensor Options for IntelliPak
Control Units

CV and VAV Unit Zone Sensor Options . .52

.........................51

Integrated Comfort™ Systems Sensors
for CV and VAV Applications

............52

Zone Sensor Installation ................53

Programmable Zone Sensors ...........54

Time Clock Option .....................56

Remote Human Interface Panel Installation 56

Mounting the Remote Human Interface
(RHI) Panel

...........................57

Wiring the Remote Human Interface .....59

Connecting to Tracer Summit ...........61

Programming the Time Clock Option .....61

Operating Principals .....................63

Control Sequences of Operation .........63

Unoccupied Sequence of Operation ......63

Occupied Sequence ....................64

Thermostatic Expansion Valve ..........66

Compressors .........................66

Unit Airside Components ...............71

Controls ................................74

Points List ............................74

RTM Module ........................74

GBAS Module .......................74

ECEM Module .......................74

Tracer™ LCI-I Module ..................74

Constant Volume (CV) Points ..........74

4 SCXG-SVX01H-EN

Table of Contents

Variable Air Volume (VAV) Points ...... 75

BCI-Points List ........................ 76

Phase Monitor ....................... 76

Unit Control Components .............. 76

RTM Module Board -

Standard on all Units ................ 76

Compressor Module (MCM) -

Standard on all Units ................ 78

Human Interface Module -

Standard on all Units ................ 78

Remote Human Interface Module Option 78

Waterside Module -

Standard on all water-cooled units ..... 78

Heat Module ....................... 78

Ventilation Override Module

(VOM) Option ...................... 78

Trane IntelliPak Communications

Modules .......................... 79

Exhaust/Comparative Enthalpy (ECEM)

Module ........................... 80

Ventilation Control Module (VCM) ..... 80

Generic Building Automation System

Module Option ..................... 80

Input Devices and System Functions . . . 82

Adjusting Belt Tension ...............94

Refrigerant System ....................95

Refrigerant Leak Test Procedure ........95

Brazing Procedures ..................96

System Evacuation Procedures ........97

Compressors .........................98

Scroll Compressor Failure Diagnosis

and Replacement ....................98

Components ..........................99

Coil Fin Cleaning .....................100

Piping Components ...................102

Maintenance Periodic Checklists ........102

Diagnostics ............................104

Troubleshooting ......................104

System Checks .....................104

Diagnostics ..........................104

Wiring Diagrams .......................113

Pre-Startup ............................. 85

Pre-Startup Checklist .................. 85

Start-up ................................ 86

Final Refrigerant Charge ............... 87

Start-up Procedure .................... 87

Startup Log .......................... 88

Maintenance ........................... 90

Service Access ....................... 90

Variable Frequency Drive (VFD) ....... 90

Variable Frequency Drive (VFD) -

Remote Mounted ................... 90

Air Filters ............................ 90

Inspecting and Cleaning Drain Pan ...... 90

Inspecting and Cleaning the Fan ........ 91

Supply Fan .......................... 91

Fan Drive .......................... 91

Fan Bearings ....................... 92

Fan Belt Tension .................... 93

SCXG-SVX01H-EN 5

Model Number Descriptions

Modular Series Self­Contained

Digit 1 - Unit Model

S = self contained

Digit 2 - Unit Type

C = commercial
I = industrial

Digit 3 - Condenser Medium

W = water-cooled

R = remote air-cooled

Digit4-Development Sequence

G = modular series

Digit 5 - Refrigerant Circuit
Configuration

U = independent, R-410A refrigerant

Digits 6, 7 - Unit Nominal
Capacity

20 = 20Tons (water or air cooled)
25 = 25Tons (water or air cooled)
30 = 30Tons (water cooled only)
32 = 32Tons (air cooled only)
35 = 35Tons (water cooled only)

Digit 8 - Unit Voltage

6 = 200 volt/60 hz/3 ph
4 = 460 volt/60 hz/3 ph
5 = 575 volt/60 hz/3 ph

Digit 9 - Air Volume/Temp
Control

2 = I-Pak & VFD & supply air temp
ctrl
3 = I-Pak & VFD w/ bypass & supply

air temp ctrl

4 = I-Pak w/o vol. ctrl, w/ zone temp

cool

5 = I-Pak w/o vol. ctrl, w/ zone temp

heat/cool

6 = I-Pak w/o vol. ctrl, w/ supply air

temp ctrl

8 = thermostat interface

Digits 10, 11 - Design Sequence

** = Factory Assigned

Digit 12 - Unit Construction

A = vertical discharge

B = vertical discharge with double

wall
C = horizontal discharge
D = horizontal discharge w/ double

wall
E = vertical discharge, ship separate
F = vert. dis. w/ double wall,

ship sep.
G = horizontal discharge, ship

separate
H = horiz. dis. w/ double wall,

ship sep.

Digit 13 - PlenumType

B = std plenum w/ factory cut holes
C = low plenum w/ factory cut holes
E = std plenum w/ field cut holes
F = low plenum w/ field cut holes
H = std plenum double wall (perf)

w/ field cut holes

J = low plenum double wall (perf)

w/ field cut holes

L = std. plenum w/factory cut holes,

ship separate

M = low plenum w/ factory cut holes,

ship separate
P = std plenum w/ field cut holes,
ship

separate
R = low plenum w/ field cut holes,

ship separate
U = std plenum double wall (perf) w/

field cut holes, ship separate

V = low plenum double wall (perf) w/

field cut holes, ship separate
0 = without plenum

Digit 14 - MotorType

2 = ODP motor
3 = TEFC motor

Digits 15, 16 - Motor HP

05 = 5 hp
07 = 7.5 hp
10 = 10 hp
15 = 15 hp
20 = 20 hp
25 = 25 hp

Digits 17, 18, 19 - Fan RPM

085 = 850 rpm
090 = 900 rpm
095 = 950 rpm
100 = 1000 rp m
105 = 1050 rpm
110 = 110 0 r p m
115 = 1150 rpm
120 = 1200 rpm
125 = 1250 rpm
130 = 1300 rpm
135 = 1350 rpm
140 = 1400 rpm
145 = 1450 rpm
150 = 1500 rpm
155 = 1550 rpm
160 = 1600 rpm
165 = 1650 rpm
170 = 1700 rpm
175 = 1750 rpm
180 = 1800 rpm
185 = 1850 rpm

Digit 20 - Heating Type

A = steam coil, LH
B = hot water coil, LH
C = electric heat, 1 stage
F = hydronic heat ctrl interface
G = elec. heat ctrl interface,1 stage
K = steam coil ship separate, LH
L = hot water coil ship separate, LH
M = steam coil, RH
N = hot water coil, RH
P = steam coil ship separate, RH
R = hot water coil ship separate, RH

T = hi-cap. hot water coil, LH

U = hi-cap hot water coil, LH, ship

sep
V = hi-cap hot water coil, RH
W = hi-cap hot water coil, RH, ship

sep

0 = none

Digit 21 - Unit Isolators

A = isopads

B = spring isolators

0 = none

Digit 22 - Unit Finish

1 = paint - slate gray

2 = protective coating

3 = protective coating w/ finish coat

Digit 23

0 = none

Digit 24 - Unit Connection

1 = disconnect switch

2 = terminal block

3 = dual point power

Digit 25 - Industrial Options

A = protective coated evaporator coil

B = silver solder

C = stainless steel screws

D = A and B

E = A and C

F = B and C

G = A, B and C

0 = none

Digit 26 - Drain PanType

A = galvanized sloped

B = stainless steel sloped

Digit 27 - Waterside Economizer

A = mechanical clean full capacity

(4-row)

B = mechanical clean low capacity

(2-row)

C = chemical clean full capacity

(4-row)

D = chemical clean low capacity

(2-row)

E = mechanical clean full capacity

(4-row) ship separate

F = mechanical clean low capacity

(2-row) ship separate

G = chemical clean full capacity

(4-row) ship separate

H = chemical clean low capacity

(2-row) ship separate

0 = none

6 SCXG-SVX01H-EN

Model Number Descriptions

Digit 28 - Ventilation Control

B = airside econ w/Traq™ damper

(top O/A inlet)

C = airside econ w/ standard

dampers (top O/A inlet)

E = airside econ w/ Traq™ damper

and comparative enthalpy
(top O/A)

F = airside econ w/ std dampers and

comparative enthalpy (top O/A)

H = none/ventilation for 2-position

control interface
J = airside economizer interface
K = airside economizer interface w/

comparative enthalpy
0 = None

Digit 29 - Water Piping

A = RH condenser connection

B = LH condenser connection
C = RH basic piping
D = LH basic piping
E = RH intermediate piping
F = LH intermediate piping
J = RH basic w/ flow switch
K = LH basic w/ flow switch
L = RH intermediate w/ flow switch
M = LH intermediate w/ flow switch
0 = none

Digit 30 - Condenser Tube Type

A = standard condenser tubes

B = 90/10 CuNi condenser tubes
0 = none

Digit 31 - Compressor Service

Valves

1 = with service valves
0 = none

Digit 32 - Miscellaneous System
Control

1 = timeclock
2 = interface for remote HI (IPCB)
3 = dirty filter switch
4 = 1 and 2
5 = 1 and 3
6 = 2 and 3
7 = 1, 2, and 3
0 = none

Digit 33 - Control Interface
Options

A = Generic BAS Module; 0-5 VDC

(GBAS)

B = Ventilation Override Module

(VOM)
D = Remote Human Interface (RHI)
G = GBAS & VOM
H = GBAS & RHI
J = VOM & RHI
M = GBAS & VOM & RHI
N = BACnet Communications

Interface (BCI)
P = BCI and GBAS
Q = BCI and VOM
R = BCI and RHI

T = BCI and GBAS and VOM

U = BCI and GBAS and RHI

V = BCI and VOM and RHI
W = BCI and GBAS and VOM and RHI

0 = None
1 = LonTalk Comm5 Interface (LCI)
2 = LCI and GBAS
3 = LCI and VOM
4 = LCI and RHI
5 = LCI and GBAS and VOM
6 = LCI and GBAS and RHI
7 = LCI and VOM and RHI
8 = LCI and GBAS and VOM and RHI

Digit 34 - Agency

T = UL agency listing

0 = none

Digit 35 - Filter Type

1 = 2-inch construction throwaway
2 = 2-inch med eff. throwaway

Digit 36 - Miscellaneous Control
Option

A = low entering air temp. protect

device (LEATPD)
B = high duct temp t-stat
C = plenum high static switch
D = kit for heat mode output (w/t’stat)
E = A and B
F = A and C
G = B and C
H = A, B, and C
0 = None

SCXG-SVX01H-EN 7

Model Number Descriptions

Self-Contained Ship-

With Accessory

Model Number

Digit1-Parts/Accessories

P = parts/accessories

Digit 2 - Unit Model

S = self-contained

Digit 3 - Shipment

W = with unit

Digit4-Development Sequence

F = signature series
G = modular series

Digit5-Sensors and Other

Accessories

S = sensors

Digit6-Sensors and

Thermostats (Field Installed)

A = BAYSENS077 - zone temp only

(CV and VAV)

B = BAYSENS073- zone temp with

timed override button (CV and

VAV)

C = BAYSENS074 - zone temp with

timed override button, setpoint
dial (CV and VAV)

E = BAYSENS108 - CV zone sensor

-dual setpoint, man/auto
changeover

F = BAYSENS110 - CV zone sensor-

dual setpoint, man/auto
changeover w, indicastor lights

G = BAYSENS119 - CV/VAV program-

mable night setback Sensor

H = BAYSENS021 - VAV zone sensor

with indicator lights

K = BAYSTAT150 2H/2C ProgTstat w/

BAYSTAT077 Remote Sensor
L = outside air temperature sensor
kit
M = outside air humidity sensor kit
N = BAYSTAT155 3H/2CTstat
P = BAYSTAT150 2H/2C

ProgrammableTstat
0 = none

Digit 7 - Mixed Air Temperature
Protection Kit (Field Installed)

1 = mixed air temperature protection

kit
0 = none

Digit 8 - Carbon Dioxide Sensor
(Field Installed)

1 = carbon dioxide sensor kit
0 = none

Digit9-Future Option

0 = none

Digits 10, 11 - Design Sequence

** = Factory Assigned

Remote Air-Cooled Condenser

Digit 1 - Unit Model

C = Condenser

Digit 2 - Unit Type

C = Commercial
I = Industrial

Digit 3 - Condenser Medium

R = Remote

Digit4-Development Sequence

C=C

Digits 5, 6, 7 - Nominal Capacity

020 = 20 Tons
029 = 29 Tons
032 = 32 Tons

Digit 8 - Unit Voltage

4 = 460 Volt/60 Hz/3 ph
5 = 575 Volt/60 Hz/3 ph
6 = 200 Volt/60 Hz/3 ph

Digit 9 - Control Option

0 = No Low Ambient, I-Pak

A = No Low Ambient,T-stat

B = Low Ambient, I-Pak
C = Low Ambient,T-stat

Digits 10, 11 - Design Sequence

** = Factory Assigned

Digit 12 - Unit Finish

1 = Paint (Slate Gray)
2 = Protective Coating
3 = Protective Coating with

Finish Coat

4 = Unpainted Unit

Digit 13 - Coil Options

A = Non-Coated Aluminum

C = Protective Coated Aluminum

Digit 14 - Unit Isolators

0 = None

A = Spring Isolators

B = Isopads

Digit 15 - Panels

0 = None
1 = Louvered Panels

Digit 16 - Agency

0 = None

T = UL Listing

8 SCXG-SVX01H-EN

General Data

Modular Series Self-Contained Unit Components

Commercial self contained units are complete HVAC
systems used infloor-by-floor applications. Units are easy
to install because they feature a single point power
connection, factory installed and tested controls, single
water point connection, factory installed options, and an
internally trapped drain connection. Modular self­contained units can ship assplit-apart units forinstallation
ease. Split-apart units ship with a dry nitrogen charge and
require field refrigerant charging.

Units consist of multiple hermetically sealed 3-D scroll
compressors, water-cooled condensers (water-cooled
units only), an evaporator coil, dual forward curved fans,
and control panel. Air-cooled units require a remote air­cooled condenser, model CXRC. Unit controls are either
electromechanical thermostat or microprocessor controls
on IntelliPak unit.

Hermetically sealed 3-D scroll compressor motors utilize
internal motor protection and time delays to prevent
excessive cycling.

Water-cooled condensers are shell and tube type with

internal subcooler. Condensers are available as
mechanically or chemically cleanable. Evaporator fan is
double width, double inlet andforward curved witha fixed
pitch belt drive assembly. Variable frequency drives are
optional. EISA efficiency open drip proof (ODP) and totally
enclosed fan cooled (TEFC) motor options are available.

Package water-cooled units ship with full refrigerant and
compressor oil charge. Split apart water cooled, and air
cooled, units ship with dry nitrogen charge and complete
compressor oil charge.

Split apart water cooled units require field connection of
suction and liquid lines. Air-cooled units require field­piping discharge and liquid lines to remote air cooled
condenser.

All units have two refrigerant circuits that include filter

drier (field installed in air cooled), liquid line service valve,
sight glass/moisture indicator, thermal expansion valve
with a sensing bulb and external equalizing line, suction
and discharge line accessports,and high andlow pressure
cutout switches. Water-cooled units also include pressure
relief valve. Air cooled units include liquid line solenoid
valve and discharge line check valve.

Control Options

Units may be ordered with conventional thermostat
interface or IntelliPak™ Direct Digital Control (DDC).
IntelliPak controls include a Human Interface (HI) panel
with two line by forty (40) character clear English display
for easy operator interface to unit setup and control
parameters. All basic setup parameters are preset from
factory.

Human Interface Panel

HI is unit mounted and accessible without opening unit’s
front panel. It allows easy setpoint adjustment using HI
keypad. HI displays all unit operating parameters and
conditions in a clear language display, which can be
configured for either English, French, or Spanish.

Optional remote human interface (RHI) will control up to
four self-contained units, each containing an
interprocessor communications bridge (IPCB). It has the
same features as unit-mounted HI except for service
mode.

For more information on setpointdefaults, ranges and unit
programming, see IntelliPakSelf-Contained Programming
Guide, PKG-SVP01*-EN that ships with each unit.

IntelliPak™ DDC Control

IntelliPak™ DDC Control provides “smart” unit control
with safety features and control relays for pumps,
dampers, etc. Modular Series IntelliPak self-contained unit
is controlled by microelectronic controlsystem consisting
of a network of modules.These modules are referred to as
unit control modules (UCM). Inthis manual, acronym UCM
refers to the entire control system network.

These modules perform specific unit functions using

proportional/integral control algorithms.They are
mounted in the unit control panel and are factory wired to
their respective internal components. Each module
receives and interprets information from other unit
modules, sensors, remote panels, and customer binary
contacts to satisfy the applicable request; i.e.,
economizing, mechanical cooling, heating, ventilation.
See the Operation section of this manual for a detailed
description of each module’s function.

Optional Controls

Optional controls include a disconnect switch, dirty filter
switch, water flow switch (water-cooled only), supply air
temperature reset, or external setpoint inputs. Daytime
heating is available on units with electric, steam, or hot
water heat control options. Morning warmup operation is
available on all units.

The static pressure probe, zone night heat/morning

warmup, supply air temperature resetsensor options ship
separate inside the unit control panel for field installation.
For more detailed information on the unit control options,
see the Owner’s section of this manual.

SCXG-SVX01H-EN 9

General Data

Unit Nameplate

Unit nameplate, mounted on left end of unitcontrol panel,
identifies unit model number, service literature, and
wiring diagram numbers.

Figure 1. IntelliPak™ commercial self-contained

modular series unit

10 SCXG-SVX01H-EN

General Data

General Data

Table 1. SCWG/SIWG/SCRG/SIRG general data

Water-Cooled Units Air-Cooled Units

Unit Size 20 25 30 35 20 25 32

Compressor Data

Quantity 2 2 1/1 2 2 1/1 2

Nominal Ton/Comp 10 10 10/15 15 10 10/15 15

Circuits 2 2 2 2 2 2 2

Evaporator Coil Data

Rows 2 4 4 4 3 4 4

Sq. Ft. 22.5 25.0 25.0 25.0 25.0 25.0 25.0

FPF 144 144 144 144 144 144 144

Condenser Data

Minimum GPM w/o Econ 36 36 46 54 - - -

Minimum GPM w/ Econ 41 41 60 65 - - -

Maximum GPM 80 80 102 119 - - -

Evaporator Fan Data

Quantity 2 2 2 2 2 2 2

Size (Dia. x width - inches) 12 5/8"x8" 12 5/8"x9" 12 5/8"x11" 12 5/8 x11" 12 5/8"x8" 12 5/8"x9" 12 5/8"x11"

Minimum HP 5 5 5 5 5 5 5
Maximum HP 20 25 25 25 20 25 25

Minimum Design CFM 6350 7250 7250 7250 7250 7250 7250

Maximum Design CFM 8500 10,625 12,750 14,875 8500 10,625 13600

R-410A Refrigerant Data

EER 14.0 14.3 14.1 14.0 10.0 10.1 10.4

IEER (CV) 14.1 14.8 15.4 15.6 10.8 11.8 11.9

IEER (VFD) 17.1 18.1 18.2 17.7 13.4 13.3 13.8

Refrigerant Charge - lb (kg)

Circuit A 19.0 (8.6) 24.0 (10.9) 24.5 (11.1) 23.0 (10.4) See Note 3 See Note 3 See Note 3
Circuit B 19.0 (8.6) 24.0 (10.4) 23.0 (10.4) 23.0 (10.4) See Note 3 See Note 3 See Note 3

Capacity Steps - % 100/53/0 100/53/0 100/65/42/6 100/53/0

Filter Data

Quantity 4 4 4 4 4 4 4

Size (inches) 16x25x2 16x25x2 16x25x2 16x25x2 16x25x2 16x25x2 16x25x2

Quantity 4 4 4 4 4 4 4

Size (inches) 20x25x2 20x25x2 20x25x2 20x25x2 20x25x2 20x25x2 20x25x2

CCRC/CIRC Condenser
Match

Notes:

1. Compressors are Trane 3-D™scroll.

2. EER and IEER are rated in accordance to the AHRI Standard 340/360-2010. Based on 80/67°F (26.7/19.4°C) to the evaporator coil, nominal airflow

and 85-95°F (29.4-35°C) condenser water or 95° F (35° C) ambient.

3. All units operate with R-410A. Water Cooled units ship with full operating charge. Air-cooled units ship with dry nitrogen charge. Field refrigerant
system charge required. Refer to Table 2, p. 12 for amounts required.

4. Maximum cfm limits are set to prevent moisture carryover on the evaporator coil.

5. Minimum cfm limits are set to ensure stable thermal expansion valve operation at low load conditions.

6. Filter sizes are for units without hot water or steam heating coils

- - - - 20 29 32

SCXG-SVX01H-EN 11

General Data

Table 2. SCRG/SIRG self-contained and CCRC/CIRC

remote air-cooled condenser

SCRG/SIRG & CCRC/CIRC
Unit Size 20/20 25/29 32/32

No. of Refrigerant Circuits 2 2 2
Operating Charge - lbs R-410A 36.5/36.5 48.5/36 46/46
Operating Charge - kg R-410A 16.6/16.6 22/16.3 20.9/20.9
Cond. Storage Cap. - lbs R-410A 37/37 51/37 51/51
Cond. Storage Cap. - kg R-410A 16.8/16.8 23.1/16.8 23.1/23.1

Notes:

1. Refrigerant charges are listed as circuit 1/circuit 2 and provide only an
estimate. Final charge requires sound field charging practice.

2. Operating charge estimate includes the air-cooled self-contained,
remote air-cooled condenser, and 25 feet of interconnecting
refrigerant piping.

3. At conditions of 95°F (35°C), condenser storage capacity is 95% full.

4. To determine the correct amount of refrigerant needed for a particular

application, reference the Trane Reciprocating Refrigeration Manual.

5. Field piping over 25 feet requires additional refrigerant. See Table 25,

p. 37 and Table 26, p. 38 to determine amounts.

Table 3. CCRC/CIRC remote air-cooled condenser

general data

Unit Size 20 29 32

Condenser Fan Data

Number/Type/Drive 4/Prop/Direct 4/Prop/Direct 4/Prop/Direct

Size (inches) 26 26 26

HP ea. 1 1 1

Nominal Cfm 18,800 21,200 32,000

Condenser Coil Data

Circuit 1 Size (in.) 1/46x71 1/46x71 1/64x71

Circuit 2 No./Size (in.) 1/46x71 1/64x71 1/64x71

Face Area (sq. ft.) 45.4 54.2 63.1

Rows/fpf 4/144 4/144 4/144

Ambient Temperature Operating Range

Standard Ambient (°F) 50-115 50-115 50-115

Low Ambient Option

(°F)

0-115 0-115 0-115

Table 4. SCWG/SIWG/SCRG/SIRG self-contained

heating coil

Filter Data for Heating Coil

Quantity 4

Size (inches) 20x18x2

Size (mm) (508x457x51)

Quantity 8

Size (inches) 20x20x2

Size (mm) (508x508x51)

Coil Data Type

Steam Coil NS 1

Hot Water Coil,

std. cap

Hot Water Coil,

hi-cap.

Notes:

1. Hot water and steam heating coils have Prima-Flo® fins and do not
have turbulators.

2. For coil capacities, use TOPSS™ (Trane Official Product Selection
Program).

5W 1

5W 2

Size (in)

2

24 x 58

1

48 x 6211219 x 1575

1

48 x 6211219 x 1575

RowsNo.

No.

Size (mm) fpf

2

609.6x1473.242

Table 5. Waterside economizer coil physical data -

SCXG 20, 25, 30, 35

Type Rows FPF

Chemically Cleanable 2 108 50 72

Mechanically Cleanable 2 108 50 72

Chemically Cleanable 4 108 50 72

Mechanically Cleanable 4 108 50 72

(in)

Height

Length

(in)

80

108

12 SCXG-SVX01H-EN

Pre-Installation Considerations

Receiving

Receiving Checklist

Complete the following checklist immediately after
receiving unit shipment to detect possible shipping
damage.

• Inspect individual cartons before accepting. Check for
rattles, bent carton corners, orother visible indications
of shipping damage.

• If a unit appears damaged, inspect it immediately
before accepting the shipment. Make specific
notations concerning the damage on the freight bill.
Do not refuse delivery.

• Inspect the unit for concealed damage before it is
stored and as soon as possible after delivery. Report
concealed damage tothe freight line within theallotted
time after delivery. Check with the carrier for their
allotted time to submit a claim.

• Do not move damaged material from the receiving
location. It is the receiver’s responsibility to provide
reasonable evidence that concealed damage did not
occur after delivery.

• Do not continue unpacking the shipment if it appears
damaged. Retain all internal packing, cartons, and
crate.Take photos of damaged material if possible.

• Notify the carrier’s terminal of the damage
immediately by phone and mail. Request an
immediate joint inspection of the damage by the
carrier and consignee.

Notify yourTrane representative of the damage and
arrange for repair. Have the carrier inspect the damage
before making any repairs to the unit.

Ship-Separate Accessories

Field-installed sensors ship separately inside unit’s main
control panel. Extra filters, sheaves,and belts ship in unit’s
fan motor section. Condenser plugs, spring isolators, and
isopads ship in unit’s bottom left side.

Contractor Installation Responsibilities

Complete the following checklist before beginning final
unit installation.

• Verify the unit size and tagging with the unit
nameplate.

• Make certain the floor or foundation is level, solid, and
sufficient to support the unit and accessory weights.
Level or repair the floor before positioning the unit if
necessary.

• Allow minimum recommended clearances for routine
maintenance and service. Allow space at end of the

unit for shaft removal and servicing. Refer to unit
submittals for dimensions. See also

Clearances,” p. 24.

• Allow three fan diameters above the unit for the
discharge ductwork. Return air enters the rear of the
unit and conditionedsupply air discharges through the
top.

• Electrical connection knockouts are on the top, leftside
of the unit.

• Allow adequate space for piping access and panel
removal. Condenser water piping, refrigerant piping,
and condensate drainconnections are on the lowerleft
end panel.

Note: Unit height and connection locations will change if

using vibration isolators. The unit height may
increase up to 5 7/8” with spring type isolators.

• Electrical supply power must meet specific balance
and voltage requirements as described in section

“Installation - Electrical,” p. 39.

• Water-cooled units only:The installeris responsible for
providing a condenser main, standby water pump,
cooling tower, pressure gauges, strainers, and all
components for waterside piping. See

p. 32 for general waterside recommendations.

• Air-cooled units only: The installer is responsible for
providing and installing the remote air-cooled
condenser and refrigerant piping.

“Service

“Water Piping,”

Unpackaging

Commercial self-contained units ship assembled with
protective coverings over the coil and discharge openings.

Figure 2, p. 14 illustrates a typical shipping package.

Unit Protective Covers

Remove the shipping protection coverings from the
human interface panel (HI) at the control panel, the filter
box (or air inlet opening), the discharge air opening, and
optional variable frequency drive (VFD).

Supply Fan Isolators

Remove the shipping channels and mounting bolts from
beneath the fan. See Figure 4, p. 15. Open both fan
compartment access doors to access the channels.There
are four mounting points for 20-38 ton units.

Note: For 20-38 ton units, do not remove the fan

assembly shipping blocks and tie down bolts if the
fan speed is 750 rpm or less.

While keeping the fan mounting frame level, turn the fan

isolator height adjusting bolts until the fan housing P­gasket compresses 1/4” against the roof transition piece.
See Figure 4, p. 15.

SCXG-SVX01H-EN 13

Pre-Installation Considerations

Figure 2. Typical unit mounting on shipping skid

Figure 3. Fan isolator locations

14 SCXG-SVX01H-EN

Figure 4. Supply fan horizontal isolation shipping

bracket

Pre-Installation Considerations

SCXG-SVX01H-EN 15

Dimensions & Weights

Table 6. SCWG/SIWG weight, lbs.

Unit Tons Base Weight - lb (kg)

20 2227 (1010)
25 2697 (1223)
30 2765 (1254)
35 2834 (1286)

Notes:

1. All unit weights include refrigerant, water and controllers, electric
heat and valves.

2. Add 150 lbs. to total weight to obtain approximate shipping weight.

3. Split-apart unit weights are approximately: 60% total unit weight =

compressor section, 40% total unit weight = fan section.

Table 7. SCRG/SIRG weight, lbs (kg)

unit tons base weight

20 2311 (1048)
25 2380 (1079)
32 2448 (1110)

Notes:

1. All unit weights include refrigerant, water and controllers, electric
heat and valves.

2. Add 150 lbs. to total weight to obtain approximate shipping weight.

3. Split-apart unit weights are approximately: 60% total unit weight =

compressor section, 40% total unit weight = fan section.

16 SCXG-SVX01H-EN

Figure 5. SCWG/SIWG, in.

Dimensions & Weights

6.75”

SCXG-SVX01H-EN 17

Dimensions & Weights

Figure 6. SCRG/SIRG, in.

6.75”

18 SCXG-SVX01H-EN

Table 8. Detail dimensions, in.

Model A B C D E F

SCWG/SCRG 20 20 10 3/4 58 1/2 5 1/8 13 1/4 11 1/2
SCWG/SCRG 25 19 1/4 12 1/4 57 5/8 5 1/8 13 1/4 11 1/2

SCWG 30 - 35

SCRG 32

18 14 5/8 56 1/2 5 1/8 13 1/4 11 1/2

Figure 7. SCRG/SIRG/SCWG/SIWG detail “A”

electrical connections, in.

Dimensions & Weights

Note: When unit is ordered with horizontal supply,

ensure that all applicable codes are considered
when installing equipment. Special attention
should be made to over head clearances of unit/
ducting to meet code requirements.

Figure 8. Detail “B” discharge options, in.

SCXG-SVX01H-EN 19

Dimensions & Weights

Figure 9. CCRC/CIRC air-cooled condenser

AA

AB

AC

OPTIONAL LOW
AMBIENT DAMPER
(ONE DAMPER PER
CIRCUIT)

REFRIGERANT
LINE
CONNECTIONS

FRONTAL VIEW

REFRIGERANT CIRCUIT 2

REFRIGERANT CIRCUIT 1

OPTIONAL LOW
AMBIENT DAMPER

24 VOLT WIRE ENTRY HOLE SIZED

3

FOR

/4” CONDUIT

115 VOLT WIRE ENTRY HOLE SIZED FOR

3

/4” CONDUIT

SUPPLY VOLTAGE WIRE ENTRY HOLE
SIZED FOR 1” CONDUIT

B

C

(LIQUID LINE CONNECTION REFRIG. CIRCUIT 1)

(HOT GAS CONNECTION REFRIG. CIRCUIT 1)

(LIQUID LINE CONNECTION REFRIG. CIRCUIT 2)

(HOT GAS CONNECTION REFRIG. CIRCUIT 2)

Table 9. CCRC/CIRC air-cooled condenser dimensions & weight, in-lbs.

Model AA AB AC shipping weight operating weight

CCRC/CIRC 20 70 1/8 88 88 2030 1906
CCRC/CIRC 29 70 1/8 88 88 2084 1960
CCRC/CIRC 32 70 1/8 88 88 2138 2014

Table 10. CCRC/CIRC refrigerant connections, in.

Model E F G H J K L M N

CCRC/CIRC 20-32 66 7/8 14 3/8 18 1/2 24 3/4 29 5/8 7/8 5/8 7/8

Table 11. CCRC/CIRC electrical connections, in.

Model A B C

CCRC/CIRC 20-32 4 1/2 10 1/2 17 1/2

20 SCXG-SVX01H-EN

Figure 10. Hot water coil: left-hand connections

Dimensions & Weights

Table 12. Hot water coil dimensions & weight, in-lbs

A B C D E F G H J K Weight

one-row coil 53 3/4 4 7/8 73 1/2 16 5/8 6 3/4 7 1/2 23 1/8 37 1/4 1 3/4 2 1/2 415
two-row coil 53 3/4 5 1/8 73 1/2 16 5/8 6 3/4 7 1/2 22 3/8 37 1/4 2 3/4 3 5/8 510

Figure 11. Hot water coil: right-hand connections

SCXG-SVX01H-EN 21

Dimensions & Weights

40 15/16"

53 13/16"

22 1/2"

3 5/16"

15 7/8"

1"

36 15/16"

3 7/8"

9 3/8"

6 3/4"

16 15/16"

35"

PIPING CONNECTIONS
2 1/2" NPTE

STEAM INLET 1"
FEMALE CONN

CONDENSATE RETURN TRAP
1 1/2" FEMALE CONN

CONDENSATE RETURN TRAP
1" FEMALE CONN

VACUUM BREAKER 1"
FEMALE CONN

VACUUM BREAKER 1"
FEMALE CONN

30 7/8"

2 1/8"

92 3/4"

73 1/2"

10 15/16"

64 1/2"

11"

3/4" (4X) ISOLATOR
MOUNTING LOCATION
ON BOTTOM OF UNIT

VERTICAL
DISCHARGE

RIGHT VIEW

TOP VIEW

Figure 12. Steam coil: left connections

92 3/4"

73 1/2"

VERTICAL
DISCHARGE

30 7/8"

2 1/8"

14 9/16"

64 1/2"

TOP VIEW

3/4" (4X) ISOLATOR
MOUNTING LOCATION
ON BOTTOM OF UNIT

11"

Note: Steam Coil Weight 460 Lbs.

Figure 13. Steam coil: right connections

53 13/16"

36 15/16"

22 1/2"

3 5/16"

15 7/8"

40 15/16"

1"

9 3/8"

3 7/8"

6 3/4"

16 15/16"

LEFT VIEW

35"

CONDENSER
FITTINGS
1 1/2" NPTI

ELECTRICAL
CONNECTIONS

Note: Steam Coil Weight 460 Lbs.

22 SCXG-SVX01H-EN

Dimensions & Weights

Figure 14. Electric Heat Coil

Table 13. Electric heat coil dimensions & weight, in-lbs.

Unit Size A B C D Weight

20 tons 70 1/4 4 7/8 11 1/2 19 460
25 tons 70 1/4 4 1/8 11 1/2 19 460
30 - 35

tons

Note: Coil box height is 8 in.

70 1/4 2 7/8 11 1/2 19 460

Figure 16. Waterside Economizer

Table 15. Waterside economizer weight, in-lbs.

Weight

Unit size 2-row 4-row

20 - 35 tons 488 584

Figure 15. Flexible horizontal discharge plenum

Figure 17. Airside Economizer

Table 14. Flexible horizontal discharge plenum

dimensions & weights, in-lbs.

20-35 tons A B C Weight

Low height 35 17 1/4 86 1/2 262

Standard height 35 25 1/4 86 1/2 352

Table 16. Airside economizer dimensions & weight, in-lbs.

Unit Size A B C D E F (1) F (2) G (1) G (2) H (1) H (2) J K L M Weight

SCWG/SIWG 20, 25
SCRG/SIRG 20

SCWG/SIWG 30, 35
SCRG/SIRG 25, 32

36 65 5/8 37 74 1/4 6 1/8 56 1/2 49 3/4 23 1/4 20 1/2 5 5/8 7 20 1/2 17 1/8 12 49 3/4 273

36 65 5/8 37 74 1/4 6 1/8 61 3/8 62 3/4 28 1/8 20 1/2 3 1/4 7 20 1/2 17 1/8 5 1/2 62 3/4 273

SCXG-SVX01H-EN 23

Dimensions & Weights

Figure 18. Detail “B” (top) and Detail “A” (bottom)

Table 17. Service and code clearance requirements

Side Distance Purpose

42 in.

front

(20-38 tons)
18 in.

left

36 in.

77 in.
right 36 in. provides uniform airflow
inlet 18 in. provides uniform airflow

NEC code requirement
air-cooled units only

refrigeration & waterside component service
fan shaft removal

Service Clearances

See Figure 19, p. 24 andFigure 20, p. 24 for recommended
service and code clearances.

Figure 19. Top view CCRC/CIRC 20, 29, 32

96” (2132 mm)

48”

(1066 mm)

96” (2132 mm)

Table 18. Service and code clearance requirements

Side Distance Purpose

42 in.

front

(20-38 tons)
18 in.

left

36 in.
77 in.

right 36 in. provides uniform airflow

inlet 18 in. provides uniform airflow

NEC code requirement
air-cooled units only

refrigeration & waterside component service
fan shaft removal

Note: When unit is ordered with horizontal supply,

ensure that all applicable codes are considered
when installing equipment. Special attention
should be made to overhead clearances of unit/
ducting to meet code requirements.

Figure 20. Top view of self-contained unit showing

recommended service and code clearances

air inlet

18” minimum

48”
(1066 mm)

Control

Panel

See

table

42” minimum

Control Panel

36”
minimum

24 SCXG-SVX01H-EN

Installation - Mechanical

Unit Handling Procedures

WARNING

Improper Unit Lift!

Test lift unit approximately 24 inches to verify proper

center of gravity lift point. To avoid dropping of unit,
reposition lifting point if unit is not level. Failure to
properly lift unit could result in unit dropping and
possibly crushing operator/technician which could
result in death or serious injury and possible equipment
or property-only damage.

WARNING

Heavy Objects!

Ensure that all the lifting equipment used is properly
rated for the weight of the unit being lifted. Each of the
cables (chains or slings), hooks, and shackles used to
lift the unit must be capable of supporting the entire
weight of the unit. Lifting cables (chains or slings) may
not be of the same length. Adjust as necessary for even
unit lift. Other lifting arrangements could cause
equipment or property damage. Failure to follow
instructions above or properly lift unit could result in
unit dropping and possibly crushing operator/
technician which could result in death or serious injury.

Figure 21. Assembled unit gravity block location

Before lifting the unit or modular component, determine
the approximate center of gravity for lifting safety. See

Figure 21, p. 25 for assembled modular units and
Figure 22, p. 26 for split-apart units.The center of gravity

may vary slightly within the gravity block depending on
unit options.

Always test-lift the unit todetermine the exactunit balance

and stability before hoisting it to the installation location.
See Figure 23, p. 26 and Figure 24, p. 27 for typicalrigging
procedures and proper rigging equipment usage.

Table 19. Gravity block dimensions

Model A B C D

SCWG 36 14 38 12

SCRG 36 16 40 12

SCXG-SVX01H-EN 25

Installation - Mechanical

Figure 22. Split-apart unit gravity block location

Fan Section Only

Compressor Section Only

Figure 23. Split-apart modular unit proper rigging (L) and fan section (R)

26 SCXG-SVX01H-EN

Figure 24. Assembled modular unit proper rigging

Skid Removal

The unit ships on skids to provide forklift locations from

the front or rear.The skid allows easy maneuverability of
the unit during storage and transportation. Remove the
skids before placing the unit in its permanent location.

Remove the skids using a forklift orjack. Lift one end ofthe
unit off of the skids. See Figure 21, p. 25 and Figure 22,

p. 26 for unit gravity block location. Slide the skids out and

lower the unit at the installation location.

NOTICE:

Equipment Damage!

Do not use hooks to lift unit or hook into open channels
to lift unit.This could cause unit damage

1. Position rigging sling under wood shipping skid.

2. Use spreader bars to avoid unit damage.

3. When using a forklift, exercise caution to prevent unit
damage.

4. Use the standard fork length to lift one end and drag or
pull unit while skidding the opposite end.

5. The unit center of gravity will fall within center of
gravity block at various locations depending on unit
options.

Installation - Mechanical

6. Use hooks to lift fan sectiononly.Do not hook into open
channels to lift unit.

7. See unit nameplate for unit weight.

8. Do not stack units.

Installation Preparation

Important: Before installing the unit, perform the

following procedures to ensure proper unit
operation.

Before installing the unit, perform the following
procedures to ensure proper unit operation.

1. Position the unit and skidassembly in its finallocation.
If unit shipped split-apart, follow the procedure in the

“Split-Apart Unit Assembly,” p. 28 before completing

this step.Test lift the unit to determine exact unit
balance and stability before hoisting it to the
installation location. See Figure 23, p. 26 and

Figure 24, p. 27 for typical rigging procedures,

including cautions and proper uses of such equipment
as fork lifts, spreader bars, and hooks.

2. Test lift the unit to determine exact unit balance and
stability before hoisting it to the installation location.
See

“Unit Handling Procedures,” p. 25 for proper

rigging procedures and cautions.

3. Remove the skids from under the unit. See “Skid

Removal,” p. 27.

4. Remove the protective shipping covers from the unit.

5. Verify isolators are properly tightened for operation.
See

“Unit Vibration Isolator Option,” p. 29.

Note: Unit height and connection locations will change if

external vibration isolators are used.The unit may
be raised an additional 5-7/8 inches with spring­type isolators.

Note: Unit height and connection locations will change if

the unit is constructed to be split-a-part in the field.
See unit submittal drawings for connection
locations.

6. Tighten compressor isolator mounting bolts.Torque to
18 ft. lbs. (± 2 ft. Lbs.)

7. Electrical supply power must meet specific balance
and voltage requirements, as described in section

“Installation - Electrical,” p. 39.

8. Water-cooled units only (model SCWG): The installer
must furnish andinstall a condenser mainand standby
water pump, cooling tower, pressure gauges and all
components for the waterside piping. See

Waterside Recommendations: CoolingTowers,” p. 32.

9. Air-cooled units only (model SCRG): These units
require field-installation of a remote air-cooled
condenser and refrigerant piping. See

System,” p. 36.

“General

“Refrigerant

SCXG-SVX01H-EN 27

Installation - Mechanical

Split-Apart Unit Assembly

1. Ensure the tagging information on the fan section
nameplate matches that on the compressor
nameplate.

2. Remove the connector brackets holding the sheet
metal shipping cover on compressor section. Retain
brackets and screws.

3. Remove shipping cover from the compressor section
and verify the ship-with package contains:

a. suction and liquid line couplings

b. insulation

c. sheet metal screws

4. Lift fan section onto the compressor section using the
rigging method in

5. Remove skid from the fan section, placing the fan
section onto the compressor section. Reference

Figure 26, p. 29.

6. Install the connection brackets with the sheet metal
screws (referenced in step 2) on all sides of the unit.
Reference Detail “A” in

7. Removethe unit panels labeled RU and RL in Figure 25,

p. 28. To remove panels, first remove the four shipping

screws located in the corner of each panel. Next, turn
the remaining 1/4 turn fasteners to the unlatch
position.The panel is supported by a “lip” channel.So,
lift the panel up and off the unit to remove it. See Detail

“A” i n

Figure 26, p. 29.

8. Connect the drain hose to the drainpan outlet fitting
and secure it with the drain hose clamp provided.

9. See “Refrigerant System,” p. 36 for piping procedures.

10. Remove panel FLR and open the bottom control panel
door, FLL. Pull the fan motor leads (coiled in the fan

Figure 25. Modular unit panel description and internal connections

Figure 23, p. 26.

Figure 26, p. 29.

section) through the knockout in the bottom of the fan
section to the control panel. Ensure that the bushing is
installed in the hole to prevent the wires from chafing.
Refer to the unit wiring diagrams to connect the fan
motor leads properly and ensure correct phase
sequencing.

IntelliPak Units (UCM) Only

11. Remove panels FML, FMM, and FMR.

12. Pull the circular plug connector (CPC) from the
compressor section through the knockouts into the fan
section. Install the bushings (provided on the wiring
harnesses) in the knockouts.\

13. Using the CPC wiring diagram, connect the male CPC
to the female CPC in the top control panel.

14. If the unit has the mixed air temperature option, route
the capillary tube on back of the filter rack.

Units with Thermostat Only

15. Remove panel FMR. See Note 1 on Figure 25, p. 28.

16. Pull frost protection wires from the bottom control
panel through knockouts in bottom of fan section.
Route wires to the appropriate frost protection
switches on the evaporator coil. Reference the unit
wiring diagrams to connect frost protection wiring
connectors.

Air-Cooled Units Only

17. Route the refrigerant circuit wires for circuits 1 and 2
from the bottom control panel through the knockouts
to the solenoid valves.The solenoid valves are located
in the liquid refrigerant lines on the right-hand side of
the unit. Refer to the unit wiring diagrams to make
splice connections.

28 SCXG-SVX01H-EN

Figure 26. How to assemble the modular unit

Installation - Mechanical

Unit Vibration Isolator Option

If your job requires external vibration isolation, two
options are available: isopads or spring-type isolators.
Isopads should be placed under the unit at locations
indicated on the factory-provided isolator sheet.

Set the spring-type isolators (Figure 27, p. 29) in position
after the unit is removed from skids before making
electrical, piping, or duct connections. All units require a
minimum of four isolators per unit. But some may require
six isolators, depending upon unit options.

Note: Trane strongly recommends you consult a

vibration specialist before double-isolating the
unit. Double isolation is not recommended.

If you decide to externally isolate the unit, use spring-flex,
type CP isolators.The spring number is marked on the
outer housing. See Figure 27, p. 29.

To install external isolators, complete the

following procedure.

1. Locate the isolators under unit base at the locations
indicated on the factory-provided isolator placement
sheet. Lift one end of the unit at a time to position
isolators to the floor, using anchor bolts.

2. Level the unit by adjusting isolator heights. Unit
weight may cause the upper housing to rest on the
lower housing of the spring isolators.The isolator
clearance shown in the side view of
must be 1/4 - 1/2 inches.To increase the clearance, lift
the unit off the isolator and turn the leveling bolt
counterclockwise. Recheck the unit level and the
housing clearances. Maximum allowable difference

Figure 27, p. 29,

between isolator heights is 1/4 inch. Shim as required
under the isolators.

Note: The compressors and fan assembly are internally

isolated on most units. Due to this, the addition of
external isolation devices (spring mounting
isolators) is at the discretion of the building or
HVAC system designer.

Figure 27. Optional spring isolator dimensional data

SCXG-SVX01H-EN 29

Installation - Mechanical

Duct Connections

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors. Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect power
and discharge capacitors before servicing could result
in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

Return air enters the rear of the unit and conditioned
supply air discharges through the top. Attach supply air
ductwork directly to the unit’s top panel, around the fan
discharge opening. A duct collar is not provided.

Note: Units equipped with the flexible horizontal

discharge plenum option may include a duct collar
when holes are factory cut. If discharge openings
are field-cut, refer to the “Plenum Installation”
section.

Install all air ducts accordingto the National Fire Protection

Association standards for the “Installation of Air

Conditioning and Ventilation Systems other than
ResidenceType (NFPA 90A) and ResidenceType Warm Air
Heating and Air Conditioning Systems (NFPA 90B).

Make duct connections to the unit with a flexible material
such as heavy canvas. If a fire hazard exists,Trane
recommends using Flexweave 1000, type FW30 or
equivalent canvas. Use three inches for the return duct
and three inches for the discharge duct. Keep the
material loose to absorb fan vibration.

Note: The compressors and fan assembly are internally

isolated.Therefore, external isolation devices
(spring mounting isolators) are at the discretion of
a vibration specialist consulted by the building or
HVAC system designer.

Figure 28. Duct connection recommendations

Discharge
Duct

3-inch
Flexible
Duct

Run the ductwork straight from the opening for a
minimum of three fan diameters. See Figure 28, p. 30.
Extend remaining ductwork as far as possible without
changing size or direction. Do not make abrupt turns or
transitions near the unit due to increased noise and
excessive static losses. Use elbows with splitters or
turning vanes to minimize static losses.

Poorly constructed turning vanes may cause airflow
generated noise. Align the fan outlet properly with the
ductwork to decrease noise levels in the duct and to
increase fan performance. To complete trunk ductwork to
the VAV terminal units, refer to the VAV box manuals for
specific requirements. Check total external static
pressures against fan characteristics to be sure the
required airflow is available throughout the ductwork.

To achieve maximum acoustical performance, minimize

the duct static pressure setpoint

3 Fan
Diameters

Return
Air

Plenum

Before installing theplenum attach the insulation strip that
ships with the plenum. See Figure 29, p. 31 for proper
insulation location. Align the plenum front with the
control panel side of the unit. Using the strips and screws
provided, secure the plenum to the unit.

Treat field-cut holes to prevent fiberglass from entering

the airstream.

Note: Plenum insulation must be applied properly to

prevent air bypass around the plenum. See

Figure 29, p. 31.

30 SCXG-SVX01H-EN

Figure 29. Correct plenum insulation placement

Plenum Bottom View

Dashed line indicates correct insulation placement.

Airside Economizer Installation

Unit Handling

1. Hoist the damper cabinet to the installation location
with straps positioned under the skid as shown in

Figure 30, p. 32. Use spreader bars to prevent unit

damage during lifting.

2. With the damper cabinet at its final location (near the
unit), remove the screws securingit to the skid fromthe
side flanges. Retain these screws for later use.

Unit Preparation

3. The support legs are secured to the skid, and the
hanging bracket is secured with wire ties to an inside
flange near the cabinet’s base. Remove the C-channel
collar and install it on the unit, if not already installed.

4. Remove the roll of 1/8” thick gasket from the damper
cabinet’s W-supports, and apply it to the C-channel
collar mounted on the rear of the unit.This gasket will
provide a seal between the damper cabinet and the
unit.

5. Attach the legs (with screws provided) to the leg
brackets located on the damper’s base.

6. Attach a field-provided clevis of suitable strength ( > 1/
2” ), to each of the corner lifting brackets through the
7/8” diameter holes.

7. Attach to the clevises a means of lifting the damper
cabinet from its skid.

Installation - Mechanical

11. Lower the damper cabinet until the holes in its side
flanges are aligned with the holes in the C-channel
collar. Install screws removed in step 3 through the
damper cabinet’s side flanges and into the C-channel’s
corresponding holes.

12. Attach ductwork to the top and back dampers
according to local codes.

Field Wiring Connections

WARNING

Proper Field Wiring and Grounding
Required!

All field wiring MUST be performed by qualified

personnel. Improperly installed and grounded field
wiring poses FIRE and ELECTROCUTION hazards.To
avoid these hazards, you MUST follow requirements for
field wiring installation and grounding as described in
NEC and your local/state electrical codes. Failure to
follow code could result in death or serious injury.

13. Open the damper cabinet’s door and connect the

factory-provided plug from the actuator to the
factory-provided plug in the unit’s filter section.

14. Cabinets withTRAQ dampers only: Unroll the two
rolls of pneumatic tubing located inside the damper
cabinet. Route these tubes through the cabinet’s front
upper panel (0.25 dia. holes provided). Connect them
to the two pneumatic tubes protruding from the
customer electrical connection panel on the unit. Be
sure to connect like tubes to each other (black to black,
white stripe to white stripe).

15. Cabinets with TRAQ dampers only: Locate the

“bullet” sensor and rolled up wiring in the unit’s filter

section. Route it into the damper cabinetand insert the
sensor into the sensor mounting clip attached to
underside of one of theTraq dampers.

Unit Installation

8. Slowly raise the damper cabinet from its skid.

9. Attach the hanging bracket across the front of the
damper cabinet. Position it with its short flange
pointing to four o’clock, and secure it with screws
provided. See

10. Lift the damper cabinet and position it such that the
hanging bracket ispositioned over the unit’s C-channel
collar.

SCXG-SVX01H-EN 31

Figure 30, p. 32.

Installation - Mechanical

Figure 30. Proper lifting of the airside economizer (top)

and proper installation of the airside
economizer option (bottom)

Note: Four condenser waterline drain plugs ship in a bag

in the unit’s left end. The installer must field install
these four plugs using pipe thread sealer. An
additional plug is provided for units with a
waterside economizer.

1. Install the vent plugs in the economizer coil headers
and condenser manifolds.These plugs ship in a bag
with the condenser drain plugs.

2. Attach the water supply line to the inlet connection,
and the return line to the outlet connection. Entering
and leaving water connections for all condensers are
factory manifolded and require only single
connections for entering and leaving water. If the unit
has a waterside economizer and/or control valves, the
factory pipes between these components.

3. If using a cooling tower, refer to Figure 32, p. 33 for a
typical piping circuit from the unit.

4. Ensure the water pressure to the unit does not exceed
400 psig.

Note: To prevent water pump damage, design system

piping to provide relief when using energy saving
waterside economizer valves.

Water Piping

Condenser Connections

WARNING

High Pressure Water!

Provide relief valves on system water piping to prevent
instantaneous release of high pressure water. Failure to
provide relief valves could result in death or serious
injury or water pump damage or unit failure.

Condensate Drain Connections

The condensate drain is internally trapped. Condensate

drain connections are on the unit’s right side. Connect
condensate drain piping to the 1 1/4“ NPT female fitting,
using at least7/8” OD copper or 3/4” ODiron pipe. Pitch the
condensate line downward a minimum of 1/2” for each 10'
of horizontal run, away from the unit. Be sure to install the
condensate drain “P” trap drain plug. Before starting the
unit, fill the trap with water to prevent negative pressure in
the fan section from impeding condensate flow.To
facilitate drain pipe cleaning, install plugged tees in place
of 90°elbows.

General Waterside Recommendations: Cooling Towers

Cooling tower control affects the unit cycle rates.
Condenser water temperature swings from 10-15°F may
cause excessive compressor, water valve, and unit
cycling. Be sure to set the tower controls to minimize
compressor/unit cycling.

Table 20. Water connection sizes

Unit Size Direct Condenser Factory Piped

SCWG 20-35 1-1/2 NPT 2-1/2 NPT

Condenser water piping knockouts are in the lowerleft end
panel. If necessary, remove insulation to gain access. All
field installed piping must conform to applicable local,
state, and federal codes.To complete condenser water
connections follow the procedure below.

32 SCXG-SVX01H-EN

Figure 31. Direct condenser connections

Waterside Piping Arrangements

Install a condenser water pump between the coolingtower
(either open or closed) and the self-contained unit. Layout
the remainder of the system’s condenser piping inreverse
returns.This helps balance the system by equalizing the
length of supply and return pipes. Multistory buildings
may use a direct return system with balancing valves at
each floor.

Installation - Mechanical

Install the supply riser and its return in close proximity.
Furnish both with permanent thermometers to check the
waterside balance during start-up and routine
maintenance checks.

Also, include strainers at each pump inlet and unit. Install

drain valves at the riser’s base to allow drainage points for
system flushing during start-up and routine maintenance.
For condenser draining and header removal, include a
shutoff/balancing valve on the entering and leaving
waterside pipes, drain tees, and unions of each unit.

Note: Unit does not have floor drains.

Water Temperature Requirements

Do not allow the entering water temperature to go below
54°F (12.2°C) on units with constant water flow (basic
piping).This will cause the compressors to shut down and
the mechanical cooling function will lockout. However, the
economizer (if enabled) will continue to function.The
compressors will reset when the entering water
temperature reaches 58°F (15°C).

Units with variable water flow (intermediate piping) have
a modulating condensing pressure control valve that
allows compressor operation down to entering water
temperatures of 35°F (2°C).

For more informationon constant and variable water flow,
see the Sequence of Operation section of this manual.

Note: Units with a waterside economizer can be set from

the human interface panel for variable or constant
water flow.

Figure 32. Condenser water piping components for cooling tower system

SCXG-SVX01H-EN 33

Installation - Mechanical

Waterside Economizer

Installation Procedure

1. Loosen and pull all end devices that go through the
bushing on the filter rack (upper right corner of rack).

2. Remove the filter rack from the back of the unit by
removing the 1/4” hex head screws from the top and
bottom of the filter rack assembly.The filter rack
assembly will hang on the unit when the screws are
removed. Remove the filter rack by lifting it up off the
unit.

3. Remove the economizer from the crate and position it
behind the unit with the headers on the left side, when
facing the back of the unit. Remove the plastic
envelope that is taped to the economizer box
assembly.This envelope contains the gasket that must
be installed onto the vertical side flanges of the box.

4. Install the pressure sensitive gasket to the unit side of
the vertical flange on the economizer box.

5. Hang the economizer on the unit as shown in

Figure 33, p. 34. Lift the economizer byusing the holes

provided in the top panel of the economizer.

6. Align economizer holes with the holes in the unit
channel. Install screws in the top (6x) and bottom (6x)
of the economizer.

7. Remove the unit’s rear middle panel and unbraze the
two copper pipes in the 2 5/8” water pipe. Do not
remove the pipe outlet blockoff panel.

8. Remove the economizer tubing assemblies from the
shipping box. Check ship-separate parts against those
shown in

p. 35, and Figure 37, p. 35. Face the front of the unit to

see which side the water pipe exits to determine if the
unit has either right or left-hand piping.

9. Assemble tubing as shown in Figure 34, p. 34 or

Figure 37, p. 35.Tack all tubesin place before brazing to

ensure proper fit-up. For right-hand piped units,install
the ball valve actuator assembly and actuator as
shown in
diagram for wiring connection points.

10. Install the pipe insulation on all pipe line to prevent
sweating

11. Install the rear panels.

12. Re-install the filter rack on the back of the economizer
coil box and affix with screws provided.

Figure 34, p. 34, Figure 35, p. 35, Figure 36,

Figure 35, p. 35. Refer to the unit wiring

Figure 33. Installing the waterside economizer

Waterside economizer must
be lifted and hooked over
flange in the opening of the
unit channel.

Install screws in
top (6x) and
bottom (6x)

Economizer

Waterside Economizer with left-hand factory

piping components

Figure 34. Detail view of ship-separate tubing

assemblies for waterside economizer left­hand piping

Unit
To p

34 SCXG-SVX01H-EN

Figure 35. Waterside economizer with left-hand factory

piping tubing assembly

B

A

Installation - Mechanical

Waterside Economizer with right-hand

factory piping components

Figure 36. Waterside economizer with right-hand

factory piping tubing assembly

E

F

D

C

Table 21. Waterside economizer ship-separate parts list -

left-hand piping

Factory

Piping Item Part # Qty. Description

Left-Hand 4001 2 Tube; 2 5/8" x 9"

X17110026250 5 Elbow; 2 5/8" x 2 5/8"

4003 1 Tube; 2 5/8" x 26 1/8"
4740 1 Tube; 2 5/8" x 33 1/2"

4009 1 *Tube; 2 5/8" x 14 7/8"
X21040098390 10 ft. *Gasket
X21080406110 1 *Insulation; 2 5/8" Rubatex
X16120203570 1 Plug; 1 1/2" Brass
X17150027060 1 Bushing; 2 1/2" ftg. x 1 1/2"
X17170031210 1 Tee; 2 5/8" x 2 1/8" x 2 5/8"

4738 1 *Tube; 2 5/8" x 19 3/4"

4007 1 Tube; 2 5/8" x 14 1/2"
X45000032020 1 roll Tape, 1.5' wide

4006 1 Tube; 2 5/8" x 19 15/16"

Table 22. Waterside economizer part descriptions - left-

hand piping

Item Part Description

A Assembly #1
B Assembly #2
C Assembly #3
D Assembly #4
E Tube; 2 5/8" x 16 7/8"
F Tube; 2 5/8" x 22 5/8"

G

A

F

B

E

D

C

Figure 37. Detail view of ship-separate tubing

assemblies for waterside economizer right­hand piping

SCXG-SVX01H-EN 35

Installation - Mechanical

Table 23. Waterside economizer ship-separate parts list -

Factory

Piping Item Part # Qty. Description

Right-Hand 4001 1 Tube; 2 5/8" x 9"

Table 24. Waterside economizer partdescriptions - right-

right-hand piping

4607 1 Tube; 2 5/8" x 17"

X17110026250 5 Elbow; 2 5/8" x 2 5/8"

4605 2 Tube; 2 5/8" x 9 1/2"

X15330177010 1 Water Valve

4008 1 *Tube; 2 5/8" x 20 1/4"
X17170031210 1 Tee; 2 5/8" x 2 1/8" x 2 5/8"
X16120203570 1 Brass Plug, 1 1/2"

X17150027060 1

4007 1 Tube; 2 5/8" x 14 1/2"

4031 1 Tube; 2 5/8" x 62

4603 1 *Tube; 2 5/8" x 11 3/4"

4006 1 Tube; 2 5/8" x 19 1/4"
X13610256010 1 *Actuator with wires
X19110028040 2 *90 Degree Conduit Fitting
X19110028040 3 ft. *1/2" Conduit

X210804060110 14 ft. *Rubatex Insulation, 2 5/8"

X45000032020 1 roll Tape, 1.5' wide
X21040098390 10 ft. *Gasket

Bushing; 2 1/8" ftg. x 1 1/

hand piping

Item Part Description

A Assembly #1
B Assembly #2
C Assembly #3

D Assembly #4

E Tube; 2 5/8" x 11 3/4"
F Tube; 2 5/8" x 20 1/4"

G Actuator Assembly

2"

Hydronic Coil Installation

Installation Procedure

WARNING

Unit Structural Integrity!

Unit panels provide structural integrity. Do not remove
more than two non-adjacent panels at one time as this
could cause the plenum frame to collapse. Failure to
follow these recommendations could result in death,
serious injury or equipment damage.

These instructions are for steam and hot water coil

installation. Hydronic coil assembly has a full coil, piping,
a modulating temperature control valve, and a disc

temperature limit device located in unit near fan on motor
frame. Hydronic coils are available with either right or left­hand pipe connections.Piping connections areidentical to
unit piping. For example, for right-hand unit piping,
hydronic coil will have right-hand connections.The
hydronic coil assembly has temperature controls to keep
the unit’s internal cabinet temperature below 105°F to
prevent motor and bearing damage.

1. Remove filter rack from back of unit. Remove the 1/4­inch hex head screws from the top and bottom of the
filter rack assembly.The filter rack assembly will hang
on the unit when the screws are removed.The filter
rack can now be removed by lifting up on the filterrack.

2. Remove the hydronic coil from crate and position it
behind unit with open side facing unit evaporator coil
inlet. Remove the plastic envelope taped to coil box
assembly.This envelope contains the mounting
screws needed to attach the coil box to theunit andthe
gasket required on the vertical side flanges of the box.

3. Install the pressure sensitive gasket to the unit side of
the vertical flange on the coil box in two places.

4. Install 2” x 1/2” standard thread eyebolts into coil lift
plates to raise coil to height necessary to attachit to the
unit.Top panel includes a “J” hook to allow hanging,
similar to filter rack. Align holes so coil hangs on unit.
If unit has dirty filter option, connect static pressure
tube to unit before bolting coil in place. Locate static
pressure tubing on unit evaporator coil and route
through the knockout in the top corner of the coil box.

5. Align the hydronic coil with the holes in the unit
channelor waterside economizer option.Move the coil
box up against the unit and install using six mounting
screws in the top and six in the bottom of the coil box.

6. Remove the valve and pipe cover on the coil box.
Connect the wires that are coiled in the coil box,
referring to the wiring diagram installed on the unit
control panel door. Route wires into the unit through
knockouts in the top of the box.

7. Reinstall the filter rack on the back of the heating coil
rack. If the unit has the waterside economizer option,
the filter rack will require additional support legs.

Refrigerant System

Trane Water Cooled Self Contained units are available in

complete system or a "Split Apart" configuration.
Complete systems are factory charged with R-410A
refrigerant. Split Apart modules have a nitrogen holding
charge and require field connection and charging.

Trane Air Cooled Commercial Self Contained and

Condenser units ship with a dry nitrogen holding charge.

Before installing refrigerantpiping verify holding charge is
present. Momentarily depress the CSC suction or
discharge line (and Condenser liquid line) access port
valves.

If charge is present continue with piping installation.

36 SCXG-SVX01H-EN

If no nitrogen escapes the access valve, leak test the unit
refrigerant system to determine the leak source, and
repair. See Maintenance section, “Refrigerant LeakTest

Procedure,” p. 95. After finding leak, remove test pressure

and repair leak using proper brazing procedures. See
Maintenance section, “Brazing Procedures,” p. 96. Retest
unit(s) to ensure all leaks are repaired. Continue with
piping installation.

Interconnecting Piping

Refrigerant piping must be properly sized and applied.

These two factors have a significant effect on both system

performance and reliability.

Split Apart Units Only:Join liquid andsuction lines with
pipe sections provided. Use proper brazing procedures.

Using Table 25, p. 37, select proper liquid and discharge
line size. Unit connection sizes are also shown. Install
interconnecting piping using proper installation and
brazing procedures.

Work on only one circuit at a time to minimize system

exposure to potentially harmful moisture in the air.

Before installing piping verify compressor oil levels are
near top of sight glass or above.

Note: CSC units (and replacement compressors) ship

fully charged with POE oil from the factory. Scroll
compressors use POE oil (OIL00079, quart
container or OIL00080, gallon container), DO NOT
substitute.

Capped discharge and liquid line connections are located
near bottom, left side of the indoor unit. CCRC/CIRC
connections are located in the unit front, at top.

Remove caps with a tube cutter to minimize risk of getting
chips inside piping.

Note: When facing the control panel side of the unit.

Circuit #2 is always on the left and Circuit #1 is
always on the right.

Cleanliness is extremely important during system
installation to minimize residual contaminants, such as
oxidization and scale.

Attach vacuum pump and begin evacuation as soon as

piping installation is complete.This starts system
dehydration and helps prevent POE compressor oil
contamination.This will also indicate large leaks if
vacuum does not hold (below 400 microns and hold for 2
hours). Complete LeakTest and Evacuation (for
procedures, see “Refrigerant LeakTest Procedure,” p. 95
and “System Evacuation Procedures,” p. 97 in
Maintenance section) before starting “,” p. 37..

Note: Installation of a field supplied discharge line access

port near indoor units with optional discharge line
ball valve will make high side pressure
measurements easier during leak test.

Note: UseType “L” refrigerant grade copper tubing only.

Installation - Mechanical

NOTICE:

Equipment Damage!

Compressors contain POE oil which readily absorbs
moisture directly from the air. Moisture absorbed by
POE oil is very difficult to remove by evacuation and can
cause compressor failure. To prevent contamination,
this unit shipped sealed containing dry nitrogen.
Minimize the amount of time the system is open to the
atmosphere.When open, flow dry nitrogen through the
piping to prevent atmospheric moisture from
contacting compressor POE oil.

Table 25. Refrigerant piping sizes

Air Cooled Modular Connection Size (in)

Circuit 1 Circuit 2

SXRG Size Liquid Discharge Liquid Discharge

20, 25, 32 5/8 7/8 5/8 7/8

Remote Condenser Connection Size (in)

Circuit 1 Circuit 2

CXRC Size Liquid Discharge Liquid Discharge

20, 29, 32 5/8 7/8 5/8 7/8

Interconnecting Tube Size (in)

Circuit 1 Circuit 2

SXRG/

CXRC Size Liquid Discharge Liquid Discharge

20/20 5/8 7/8 5/8 7/8
25/29 5/8 1 1/8 5/8 7/8
32/32 5/8 1 1/8 5/8 1 1/8

Preliminary Refrigerant Charging

WARNING

Confined Space Hazards!

Do not work in confined spaces where refrigerant or
other hazardous, toxic or flammable gas may be
leaking. Refrigerant or other gases could displace
available oxygen to breathe, causing possible
asphyxiation or other serious health risks. Some gases
may be flammable and or explosive. If a leak in such
spaces is detected, evacuate the area immediately and
contact the proper rescue or response authority. Failure
to take appropriate precautions or to react properly to
such potential hazards could result in death or serious
injury.

SCXG-SVX01H-EN 37

Installation - Mechanical

WARNING

Hazard of Explosion!

Use only dry nitrogen with a pressure regulator for
pressurizing unit. Do not use acetylene, oxygen or
compressed air or mixtures containing them for
pressure testing. Do not use mixtures of a hydrogen
containing refrigerant and air above atmospheric
pressure for pressure testing as they may become
flammable and could result in an explosion.
Refrigerant, when used as a trace gas should only be
mixed with dry nitrogen for pressurizing units. Failure
to follow these recommendations could result in death
or serious injury or equipment or property-only
damage.

WARNING

Hazardous Pressures!

If a heat source is required to raise the tank pressure
during removal of refrigerant from cylinders, use only
warm water or heat blankets to raise the tank
temperature. Do not exceed a temperature of 150°F. Do
not under any circumstances apply direct flame to any
portion of the cylinder. Failure to follow these safety
precautions could result in a violent explosion, which
could result in death or serious injury.

CAUTION

FreezingTemperatures!

Do not allow liquid refrigerant to contact skin. If it
does, treat the injury similar to frostbite. Slowly warm
the affected area with lukewarm water and seek
immediate medical attention. Direct contact with liquid
refrigerant could cause minor or moderate injury.

NOTICE:

Compressor Damage!

If it becomes necessary to remove or recharge the
system with refrigerant, it is important that the
following actions are taken. To prevent cross
contamination of refrigerants and oils, use only
dedicated R-410A service equipment.

• Disconnect unit power before evacuation and do not
apply voltage to compressor while under vacuum.

• Due to presence of POE oil, minimize system open
time. Do not exceed 1 hour.

• Allow the crankcase heater to operate a minimum of
24 hours before starting compressors.

• Do not allow liquid refrigerant to enter the suction
line. Excessive liquid accumulation in the liquid lines
could result in compressor damage.

• Do not operate the compressors without some
refrigerant in each circuit.

Failure to follow these instructions could result in
compressor failure.

1. Verify system leak check (including interconnecting
piping for air cooled systems) and evacuation are
complete before adding refrigerant. See “Refrigerant

LeakTest Procedure,” p. 95 and “System Evacuation
Procedures,” p. 97 in Maintenance section

2. Ensure field supplied unit disconnect is "OFF". Verify
that the unit 115 volt control circuit switch is "OFF" and
reset relays have been unplugged, to prevent
inadvertent compressor starts.

3. Turn field supplied unit disconnect "ON" to energize
crankcase heaters. Verify crankcase heaters are
operating.

4. Verify all service valves are open.

5. See CSC General data Table 1, p. 11 or Table 2, p. 12 for
unit refrigerant charge.

6. See Table 26, p. 38 for additional charge required
based on field piping size and length. Add this to the
charge amount from

Note: Step 6 not required for field piping under 25

feet, or for water cooled system.

7. At the liquid line angle valve add as much R-410A
LIQUID as possible up to, but not exceeding, total
charge amount. Depending on conditions, it may not
be possible to add more than 60% of the total charge.

This will be adequate for compressor startup. More

charge will be added after compressors are started.
Use an accurate scale to measure and record
preliminary amount of R-410A added to each circuit.

• Air Cooled Only: Add charge at the condenser

access valve or field supplied discharge line access
valve. If angle valve is used for charging, liquid line
solenoid valve should be open.

8. DO NOT add refrigerant in the suction line during
preliminary charging to minimize refrigerantin system
low side prior to compressor start.

9. Record charge amount added.

10. If total charge is not reached see “Final Refrigerant

Charge,” p. 87.

11. Verify wiring has been returned to original.

• Air Cooled Only: Verify liquid line solenoid valve

has been returned to original.

Table 26. Charge add (R-410A) - lbs per 10 ft of line

Piping Size (in) Liquid Line Discharge Line

5/8 1.07 ­7/8 2.23 0.31

1 1/8 - 0.53

(a)Amounts listed are for 10 ft of pipe above 25’. Actual requirements will

be in direct proportion to the actual length of piping.

Step 5 for the total charge.

(a)

Charge (lbs)

To charge the system:

38 SCXG-SVX01H-EN

Installation - Electrical

Unit Wiring Diagrams

Specific unit wiring diagrams are provided on the inside of
the control panel door. Use these diagrams for
connections or trouble analysis.

Supply Power Wiring

It is the installer’s responsibility to provide power supply
wiring to the unit terminal block or the non-fused
disconnect switch option.Wiring should conform to NEC
and all applicable code requirements.

Bring supply wiring through the knockout in the lower left
side of the unit control panel. Connect the three phase
wires to the power terminal block or the non-fused
disconnect switch in the control box terminals. Refer to
specific wiring diagrams andfuse information inthe unit’s
control panel.

WARNING

Hazardous Service Procedures!

The maintenance and troubleshooting procedures

recommended in this section of the manual could result
in exposure to electrical, mechanical or other potential
safety hazards. Always refer to the safety warnings
provided throughout this section concerning these
procedures. Unless specified otherwise, disconnect all
electrical power including remote disconnect and
discharge all energy storing devices such as capacitors
before servicing. Follow proper lockout/tagout
procedures to ensure the power can not be
inadvertently energized. When necessary to work with
live electrical components, have a qualified licensed
electrician or other individual who has been trained in
handling live electrical components perform these
tasks. Failure to follow all of the recommended safety
warnings provided, could result in death or serious
injury.

compressor terminals.Voltage imbalance on three phase
systems can cause motor overheating and premature
failure. Maximum allowable imbalance is 2.0%.

Voltage Imbalance

Read the voltage at the compressor terminals to determine
if it isbalanced.Voltage imbalance onthree phase systems
can cause motor overheating and premature failure.The
maximum allowable imbalance is 2.0%. Voltage
imbalance is defined as 100 times the sum of the deviation
of the three voltages from the average (without regard to
sign) divided by the average voltage. For example, if the
three measured voltages are 221,230, and 227, theaverage
voltage would be:

221 230 227++

--------------------------------------------------- - 226volts=
3

The percentage of voltage imbalance is then:

100 * (226-221)/226 = 2.2%

Phase Monitor

Unit is equipped with phase monitor in control box.The
phase monitor will protect against phase loss, imbalance
and reversal of line voltage. If a fault occurs, the red LED
will energize. While the fault condition is present, the
phase monitor interrupts the 115V control circuit. If no
faults are observed, a green LED will be energized.

Control Power

NOTICE:

Component Damage!

Unit transformers IT1, IT3, IT4, and IT5 are sized to
provide power to the unit only. Do not use these
transformers to supply power to field equipment. Field
connections to these transformers could create
immediate or premature component failures.

NOTICE:

Use Copper Conductors Only!

Unit terminals are not designed to accept other types
of conductors. Failure to use copper conductors could
result in equipment damage.

NOTICE:

Motor Damage!

Correct phase sequence is critical. If phase sequence of
the incoming line voltage is not correct, it could result
in motor damage.

In this example, 2.2% imbalance is not acceptable.

Whenever a voltage imbalance of more than 2.0% exists,

check the voltage at the unit disconnect switch. If the
imbalance at the unit disconnect switch does not exceed

2.0%, faulty unit wiring is causing the imbalance. Conduct
a thorough inspection of the unit electrical wiring
connections to locate the fault, and make any repairs
necessary.

Access the connection terminal block through the control

panel on the unit’s upper left side. All wiring should
conform to NEC and applicable local code requirements.

Be sure all wiring connections are secure. Reference the
unit specific diagrams inside the control panel.

Voltage Range

Voltages must be within +- 10% the nameplate voltage.

Ensure the unit voltage is balanced by measuring at the

SCXG-SVX01H-EN 39

Installation - Electrical

Selection Procedures

RLA = rated load amps
Compressor LRA = locked rotor amps
Fan motor LRA = locked rotor amps, N.E.C. table 430 - 150
FLA = full load amps, N.E.C.

Table 430 - 150

Voltage utilization range is ±10%

Determination of minimum circuit ampacity (MCA).
MCA = 1.25 x largest motor amps/VFD amps (FLA or RLA)
+ the sum of the remaining motor amps.

Determination of maximum fuse size (MFS) and maximum
circuit breaker size (MCB).
MFS and MCB = 2.25 x largest motor amps (FLA or RLA) +
the sum of the remaining motor amps.

For units with the dual power option, there are two
electrical circuits that need calculationsusing the formulas
above:

• circuit #1 - fans

• circuit #2 - compressors

If rating value determined does not equal a standard
current rating of over current protective device, use next
lower standard rating for the marked maximum rating.

Table 27. Number of compressors per unit

SCWG/SIWG

SCRG/SIRG

10 HP 2 2 1 ­15 HP - - 1 2

Table 28. SxWG & SxRG compressor motor electrical

data

200V 460V 575V

HP RLA LRA RLA LRA RLA LRA

10 41.4 267 18.6 142 15.8 103
15 56.9 351 25.5 197 23.1 146

Table 29. Electric heat - single stage

SCWG/SIWG SCRG/SIRG Heat 200V 460V

Size Size Kw Amps Amps

20 20 16 44.8 19.6
25 25 20 55.6 24.2
30 - 24 66.8 29.0

- 32 26 72.4 31.6

35 - 28 78 34.0

Note: Electric heat amperage should not be considered when determining

minimum circuit ampacity. The current of the unit in the heating
mode will not exceed the current of the unit in the cooling mode.

20
20

25 30

25

35
32

Table 30. CCRC/CIRC condenser electrical data

Unit
Size

Tons

20, 29, 32

Note: All motors for CCRC/CIRC units are rated at 1 hp (.7457 kW).

Rated

Voltage# Fans

200 4 4.1 20.7 17.4 20
230 4 4.1 20.7 17.4 20
460 4 1.8 9.0 7.7 15
575 4 1.4 7.2 6.0 15

FLA

(ea.)

LRA

(ea.) MCA

MFS/

MCB

Table 31. Fan motor electrical data

200V 460V 575V

HP TYPE FLA LRA FLA LRA FLA LRA

ODP 15.7 107 6.8 48 5.4 40

5

TEFC 15 125 6.7 52 5.3 41

ODP 22.3 199 9.7 84.8 7.8 61.4

7.5
TEFC 23.2 162 9.4 74 7.6 58.5

ODP 29.5 260 12.6 118 10.1 72.3

10

TEFC 27.4 195 11.9 103 9.6 83.9

ODP 43.4 271 18.9 118 15.1 94

15

TEFC 42.5 235 18.5 122.9 14.8 99

ODP 57.0 373 24.5 160.8 19.6 130

20

TEFC 56.4 320 24.5 175 19.6 140

25 ODP 69.0 438 30.4 190 24.3 152

Table 32. VFD electrical data

VFD L.I.C.

Without Bypass With Bypass

HP 200V 460V 575V 200V 460V 575V

7.5 23.8 10.6 8.8 25 11.3 9.3
10 32.2 14 11.1 31.6 14.3 11.3
15 48.3 21 16.6 47.7 21.3 15.6
20 61.9 27.6 21.4 60.9 27.3 22.3
25 78.2 34 26.3 76.5 34.3 27.3

Note: Values are at the maximum VFD input rating and not the reduced

motor values.

40 SCXG-SVX01H-EN

Installation - Electrical

0.22

0.20

0.31

0.22

0.26

0.43

14.65

8.07

13.19

10.12

10.56

4.33

5.28

Trane TR200

OK

Status

Cancel

Back

Info

Reset

On

Warn.

Alarm

Quick
Menu Menu

Main

Log

Alarm

On

Hand

Reset

OffOnAuto

BDETAIL

ADETAIL

MOUNTING BASE

BSEE DETAIL

ASEE DETAIL

0.48

0.39

Variable Frequency Drive Option (VFD)

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors.Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect
power and discharge capacitors before servicing could
result in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

NOTICE:

Use Copper Conductors Only!

Unit terminals are not designed to accept other types
of conductors. Failure to use copper conductors could
result in equipment damage.

Variable Frequency Drive Without ByPass

Table 33. W/O Bypass VFD Frame Sizes

200V 460V 575V

HP

7.5 B1 A3 A3
10 B1 A3 B1
15 B1 B1 B1
20 B2 B1 B1
25 C1 B1 B1

Notes:

1. See Figure 38, p. 41 through Figure 41, p. 44 for frame size details.

2. VFD wall-mounted by others

Figure 38. Frame A3: without bypass

Frame Frame Frame

Variable frequency drive (VFD) option can only be used

with IntelliPak units.TraneTR200 VFD and VFD w/bypass
is available from 5 to 25 hp. All VFDs are pre-configured
and run tested at factory. VFD is wall mounted.

Mounting Requirements

Proper location of the VFD is important to achieve proper
performance and normal operating life. Installation must
be in an area where it will be protected from:

• Direct sunlight, rain or moisture.

• Corrosive gases or liquids.

• Vibration, airborne dust, or metallic particles.

For effective cooling and proper maintenance, install the

VFD vertically to the ground using four mounting screws.

To ensure sufficient air space for cooling there must be a

minimum eight inch clearance above and below VFD. A
minimum 2” clearance is required on each side. Allow
enough clearance to VFD cabinet door.

See Figure 38, p. 41 through Figure 45, p. 48 for VFD
dimensions and weights.

Electrical Installation Procedure

Refer to the National Electric Code, section 310-16 for
sizing power wires. All other control wires should be
twisted shielded or twisted pair shielded, 20 - 14 AWG,
with lead length not to exceed 164 feet. When using
shielded wire, the shield sheath must be connected at the

VFD only. Refer to Unit Schematic and connection

diagrams for VFD wiring.

SCXG-SVX01H-EN 41

Weight = 14 lbs (6.350 Kg)

Installation - Electrical

0.63

0.63

AutoOnOff

Reset

Hand

On

Alarm

Log

Main

MenuMenu

Quick

Alarm

Warn.

On

Reset

Info

Back

Cancel

Status

OK

Trane TR200

9.56

19.45

0.35

0.47

0.35

0.75

0.35

0.35

DETAIL A

DETAIL B

10.28

17.87

8.27

AIR

OUTLET

AIR

INLET

MOUNTING BASE

SEE DETAIL A

SEE DETAIL B

Figure 39. Frame B1: without bypass

Weight = 51 lbs (23.133 Kg)

42 SCXG-SVX01H-EN

Figure 40. Frame B2: without bypass

Trane TR200

OK

Status

Cancel

Back

Info

Reset

On

Warn.

Alarm

Quick
Menu Menu

Main

Log

Alarm

On

Hand

Reset

OffOnAuto

0.35

0.35

0.75

0.47

0.35

0.35

BDETAIL ADETAIL

26.14

9.57

INLET

AIR

OUTLET

AIR

10.28

MOUNTING BASE

BSEE DETAIL

ASEE DETAIL

24.57

8.27

0.64

0.64

Installation - Electrical

Weight = 60 lbs (27.216 Kg)

SCXG-SVX01H-EN 43

Installation - Electrical

Trane TR200

OK

Status

Cancel

Back

Info

Reset

On

Warn.

Alarm

Quick
Menu Menu

Main

Log

Alarm

On

Hand

Reset

OffOnAuto

BDETAIL

ADETAIL

0.39

0.35

0.75

0.49

0.39

0.35

27.28

12.17

MOUNTING BASE

BSEE DETAIL

ASEE DETAIL

INLET

AIR

OUTLET

AIR

25.51

10.71

12.17

0.72

0.72

Figure 41. Frame C1: without bypass

Weight = 91 lbs (41.277 Kg)

44 SCXG-SVX01H-EN

Variable Frequency Drive With ByPass

7.63

4.72

30.81

31.92

SEE DETAIL A

SEE DETAIL B

9.73

.59

DETAIL A

.39

.35

.28

.35

DETAIL B

.39

1.45

.72

1.45

4.72

.98

2.42

3.99

5.37

Trane TR200

Status

Menu

Quick

Menu

Main

Log

Alarm

Back

Cancel

InfoOKOn

Warn.

Alarm

On

Hand

Reset

OffOnAuto

Reset

Table 34. With Bypass VFD Frame Sizes

200V 460V 575V

HP

7.5 B1 A3 A3
10 B1 A3 A3
15 B2 B1 B1
20 B2 B1 B1
25 C1 B1 B1

Notes:

1. See Figure 42, p. 45 through Figure 45, p. 48 for frame size details.

2. VFD wall-mounted by others.

Figure 42. Frame A3: with bypass

Frame Frame Frame

Installation - Electrical

Weight = 35 lbs (15.876 Kg)

SCXG-SVX01H-EN 45

Installation - Electrical

8.86 8.86

19.09

20.1021.48

12.65

0.35

0.69

0.75

0.69

0.35

SEE DETAIL A

TYP. 3 PLCS.

DETAIL A

DETAIL B

0.47

.69

SEE DETAIL B

TYP. 3 PLCS.

Trane TR200

Status

Quick
Menu Menu

Main

Log

Alarm

Cancel

Back

OK

InfoOn

Warn.

Alarm

On

Hand

Reset

OffOnAuto

Reset

Figure 43. Frame B1: with bypass

Weight = 85 lbs (38.555 Kg)

46 SCXG-SVX01H-EN

Figure 44. Frame B2: with bypass

.47

.35

.75

.69

.35

.69

8.868.86

19.09

28.17

26.79

12.65

.69

SEE DETAIL B

SEE DETAIL A

DETAIL A DETAIL B

Trane TR200

OK

Status

Cancel

Back

Info

Reset

On

Warn.

Alarm

Quick
Menu Menu

Main

Log

Alarm

On

Hand

Reset

OffOnAuto

Installation - Electrical

Weight = 105 lbs (47.627 Kg)

SCXG-SVX01H-EN 47

Installation - Electrical

11.0011.00

24.30

14.51

29.94

28.55

1.15

1.42

2.76

1.42

2.99

2.82

1.89

SEE DETAIL B

TYP. 3 PLCS.

SEE DETAIL A
TYP. 3 PLCS.

DETAIL B DETAIL A

Trane TR200

OK

Status

Cancel

Back

Info

Reset

On

Warn.

Alarm

Quick
Menu Menu

Main

Log

Alarm

On

Hand

Reset

OffOnAuto

Figure 45. Frame C1: with bypass

Weight = 145 lbs (65.771 Kg)

48 SCXG-SVX01H-EN

Installation - Electrical

Static Pressure Transducer Installation (VAV units only)

Supply air static pressure controls the inverter option. A
static pressure head assembly ships separate in control
panel for field installation in the supply air duct work.
Installer is responsible for providing pneumatic tubing.

Transducer Location

Place head assembly in an area of ductwork that will
provide an average and evenly distributed airflowpattern.
Use the following guidelines to determine an appropriate
installation location.

1. Locate static head assembly 2/3 to 3/4 down longest
duct run, in an area approximately 10 duct diameters
downstream and 2 duct diameters upstream of major
interferences, turns, or changes in duct diameter.

2. When installing pneumatic tubing between head
assembly and transducer in control panel, don’t
exceed 250ft for ¼”OD tubing or 500ft for 3/8”OD
tubing.

Installing the Transducer

To properly install the static pressure transducer:

1. Mount pressure sensing head assembly in duct with
sensing tip isin middle ofthe duct so thatit will provide
a proper pressure measurement. See Figure 46, p. 49.

2. Connect the pneumatic tubing from the sensing head
to the push-on tubing connection in the control panel.
Use a plastic static pickup tubing. Do not exceed 250
feet for 1/4“ OD tubing or 500 feet for 3/8” OD tubing.

Transducer inside control panel picks up low side or

reference pressure.

Note: If plastic tubing pulls away from a connection, trim

it back before replacing it on the fitting. Stretched
tubing may leak and cause faulty control.

Figure 46. Static pressure sensor installation

Static Pressure
Head Assembly

Duct

Electric Heat Installation

Electric heat option consists of a single stageheater andis
used in IntelliPak™ units or units with a field-installed
thermostat. Electric heater ships separate for field
installation and wiring. See Table 35, p. 49 for heater kW
per unit size. Electric heat can be installed on units with
vertical discharge. It cannot be installed on units with
plenums. See Figure 47, p. 50 and Table 36, p. 50 for
electric heat dimensional data.

Table 35. Available electric heat kW

Unit Size Heater kW

20 Tons 16
25 Tons 20
30 Tons 24
32 Tons 26
35 Tons 28

Installation Procedure

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors.Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect
power and discharge capacitors before servicing could
result in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

NOTICE:

Use Copper Conductors Only!

Unit terminals are not designed to accept other types
of conductors. Failure to use copper conductors could
result in equipment damage.

Connector
for 1/4”
Tubing

Sheet Metal Screws
(provided by installer)

SCXG-SVX01H-EN 49

NOTE: Place sensor inlet
perpendicular to airflow.

Pressure
Sensor

1. Remove fan discharge shipping covers, if not
previously done.

2. Install open-cell gasket around discharge opening on
heater.

3. Position electric heater so unit fan discharge openings
line up with electric heater openings. For a vertical
discharge unit, position electric heater as shown in

Figure 47, p. 50.

4. Use hole pattern in electric heat as a template to mark
and drill 3/16” diameter holes in unit.

5. Bolt electric heaters to unitwith ¼” sheetmetal screws.

Installation - Electrical

Note: Itis very important that electric heaters are selected

based on unit voltage and tonnage because
discharge opening sizes vary by unit tonnage.

Electric Heat CoilWiring Procedure

• Before wiring the electric heater, remove the unit

Table 36. Electric heat dimensions - english - (inches)

Unit Size B1 B2 Z

20 Tons 10 3/4 15 5/8 27 3/4
25 Tons 12 1/4 15 5/8 26 3/4

30, 32, 35 Tons 14 3/4 15 5/8 23 3/4

wiring diagram from the unit control panel and referto
the connection points.

Figure 47. Vertical discharge electric heat installation (L) and electric heater dimensions

50 SCXG-SVX01H-EN

Installation - Electrical

Standard with All IntelliPak Units

BAYSENS077

(zone temperature sensor only)

CV Unit Zone Sensor
Options

BAYSENS108

(Dual setpoint, manual/automatic
changeover sensor, accessory
model number digit6=E)

BAYSENS110

(Dual setpoint, manual/automatic
changeover sensor with system
function lights, accessory model
number digit6=F)

Zone Sensor Options for IntelliPak Control Units

Zone sensor options are available and be ordered with the unit or after the unit ships.
Following is a full description of zone sensors and their functions. See Table 44, p. 77
for the zone sensor temperature vs. resistance coefficient curve.

BAYSENS077* Description

This zone sensor module ships with all units, and can be used with BAYSENS019,

BAYSENS020, or BAYSENS021 remote sensors. When this sensor is wired to one of
these remote zone sensors, wiring mustbe 18AWG shielded twistedpair (Belden 8760
or equivalent). Refer to the specific zone sensor for wiring details. It provides the
following features and system control functions:

• Remote temperature sensing in the zone

• Morning warmup sensor

• Zone sensor for ICS™ systems

• Zone temperature averaging

When used as a remote sensor for standard zone sensor, the thermistor sensor must

be disabled.

(Possible Schematic Designation(s): 5U23, 5U26, 5U30, and 5RT5.)

BAYSENS108 & BAYSENS110 Description

These zone sensor modules are for use with cooling/heating constant volume units.
They have four system switch settings (heat, cool, auto, and off) and two fan settings

(on and auto).The zone sensor provides either manual or automatic changeover
control with dual setpoint capability.

BAYSENS108 and BAYSENS110 features and system control functions include:

• System control switch to select heating mode (HEAT), cooling mode (COOL),
automatic selection of heating or cooling as required (AUTO), or to turn the
system off (OFF).

• Fan control switch to select automatic fan operation while actively heating or
cooling (AUTO), or continuous fan operation (ON).

• Dual temperature setpoint levers for setting desired temperature.The blue lever
controls cooling, and the red lever controls heating.

• Thermometer to indicate temperature in the zone. This indicator is factory
calibrated.

(Possible Schematic Designation: 5U29)

BAYSENS110-Specific Feature: Function status indicator lights:

• SYSTEM ON glows continuously during normal operation, or blinks if system

is in test mode.

• COOL glows continuously during cooling cycles, or blinks to indicate a cooling

system failure.

• HEAT glows continuously during heating cycles, or blinks to indicate a heating

system failure.

• SERVICE blinks or glows to indicate a problem.These signals vary depending

on the particular equipment being used.

(Possible Schematic Designation: 5U29)

SCXG-SVX01H-EN 51

Installation - Electrical

CV and VAV Unit Zone Sensor Options

BAYSENS074

(Zone temperature sensor w/timed override

and local setpoint adjustment,

accessory model number digit 6 =
C)

Integrated Comfort™ Systems Sensors for CV and

VAV Applications

These zone sensor options are for use with cooling/heating Integrated Comfort

System (ICS) systems.

BAYSENS074 Description

This electronic analog sensor features single setpoint capability and timed override

with override cancellation. BAYSENS074 features and system control functions
include:

• Remote temperature sensing in the zone

• A timed override button to move an ICS or a building management system from
its “unoccupied” to “occupied” mode.

• Thumbwheel for local setpoint adjustment

• A cancel button to cancel the “unoccupied override” command.

(Possible Schematic Designation: 5U23)

BAYSENS073 Description

This electronic analog sensor features single setpoint capability and timed override

with override cancellation. It is used with aTrane Integrated Comfort system.

BAYSENS073 features and system control functions include:

• Remote temperature sensing in the zone

• A timed override button to move an ICS or a building management system from
its “unoccupied” to “occupied” mode.

• Cancel button to cancel the “unoccupied override” mode.

(Possible Schematic Designation: 5U23)

BAYSENS073

(Zone temperature sensor w/timed
override , accessory model
number digit6=B)

Figure 48. Zone sensor mounting hole locations for: BAYSENS077, BAYSENS073, BAYSENS074, BAYSENS108, and

BAYSENS110.

1-3/32 [27,43 mm]

3-5/32 [80,00 mm]

1-1/32 [26,16 mm]

RIGHT BACK

5/32 [3,81 mm] 4X

3/32 [2,00 mm]

1-3/8 [35,00 mm]

19/32 [15,00 mm]

15/64 [6,00 mm]

52 SCXG-SVX01H-EN

Zone Sensor Installation

All sensor options ship in the main control panel and are

field-installed. Programmable option installation
procedures.

Installation - Electrical

Mounting Location

Mount the sensoron the wallin an areawith good aircirculation
at an average temperature.Avoid mounting spacetemperature
sensor is areas subject to the following conditions:

• Drafts or “dead” spots behind doors or in corners

• Hot or cold air from ducts

• Radiant heat from the sun or appliances

• Concealed pipes and chimneys

• Unheated or non-cooled surfaces behindthe sensor, such as
outside walls

• Airflows from adjacent zones or other units

To mount the sensors, remove the dust cover and mount the

base on a flat surface or 2" x 4" junction box. Sensors ship with
mounting screws.

Mounting the Subbase

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors. Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect power
and discharge capacitors before servicing could result
in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

NOTICE:

Use Copper Conductors Only!

Unit terminals are not designed to accept other types
of conductors. Failure to use copper conductors could
result in equipment damage.

Remove the zone sensor cover from subbase, and mount
subbase on the wall or on a 2 x 4 junction box. Route wires
through the wire access hole in the subbase. See

Figure 49, p. 54. Seal the hole in the wall behind the

subbase.

Note: Guidelines for wire sizes and lengths are shown in

Table 37, p. 53.The total resistance of these low

voltage wires must not exceed 2.5 ohms per
conductor. Any resistance greater than 2.5 ohms

may cause the control to malfunction due to
excessive voltage drop.

Note: Do not run low-voltage control wiring in same

conduit with high-voltage power wiring.

Wiring

1. Run wires between the unit control panel and the zone
sensor subbase.To determine the number of wires
required, refer to the unit wiring diagrams.

2. Connect the wiring to the appropriate terminals at the
unit control panel and at the zone sensor subbase. In
general, zone sensor connections to the unit use the
convention of connecting zone sensor terminals to like
numbered unit terminals (1 to 1, 2 to 2, etc.).The
connection detail is shown on the unit wiring
diagrams, which are located in the unit control panel.

3. Replace the zone sensor cover back on thesubbase and
snap securely into place.

Standard Remote Sensor (BAYSENS077)

When using the remote sensor, BAYSENS077, mount it in

the space that is to be controlled. Wire according to the
interconnecting wiring diagrams on the unit.

Table 37. Zone sensor maximum lengths and wire size

Distance from Unit to

Controller Recommended Wiring Size

0-150 feet 22 gauge

151--240 feet 20 gauge

241-385 feet 18 gauge

386- 610 feet 16 gauge

611-970 feet 14 gauge

SCXG-SVX01H-EN 53

Installation - Electrical

Figure 49. Typical zone sensor installation for vertically-oriented sensors

Mounting Directly to the Wall

Mounting to Junction Box

Junc-

tion

Programmable Zone Sensors

A Check FilterTimer function is included. Filter service

countdown time can be set in one-day increments.

Activation of theTest/Configuration button located on the

bottom of the sensor performs a sensor self-diagnostic
routine and indicates hours in service.

When the BAYSENS119 is programmed for Constant
Volume or VAV control, Night Setback is initiated through

the scheduled Unoccupied time setting. When the sensor
switches to Night Setback, the outdoor dampers close and
heating/cooling functions are enabled/disabled based on
set up parameters. As building load changes, If heating/
cooling functions are enabled, the Sensor energizes self­contained unit and evaporator fan operation.The unit will
cycle heating/cooling operation throughout the
Unoccupied period as required to maintain Unoccupied
space temperature setpoints.When the Unoccupied time

The BAYSENS119 programmable night set back sensor

provides multi functional flexibility for both Constant Volume
and Variable Air Volume control.This electronic programmable
sensor includes auto or manual cooling and heating
changeover with 7 day programming. Five tactile feel buttons
located on the sensor front panel provide interface for all
programming, including initial setup for CV or VAV control.
Sensor functionality includes up to four daily programmable
periods for Occupied/Unoccupied operation, and Override. The
dynamic LCD display indicates status for System On/Off, Heat,
Cool, Fan Status,Time of Day, Occupied/Unoccupied mode,
SpaceTemperature, Space or Discharge Air Heating and
Cooling Setpoints. Additional features include Service
Indication for Heat Failure, Cool Failure, Fan Failure, andTest
Mode if system is operating in test mode.

period has expired, all heating/cooling functions return to
normal operation.

When Night Setback options are used withVAV heating/

cooling, maintain airflow through the self-contained unit
by electronically tying the VAV terminals to the
unoccupied output relay contacts on the self-contained
units low voltage terminal board, or by using changeover
thermostats. Either of these methods will assure adequate
airflow through the unit and satisfactory temperature
control of the space.

Note: Refer to BAS-SVX17*-EN for complete Installation,

Operation, and Maintenance Instructions.

54 SCXG-SVX01H-EN

Figure 50. Zone sensor mounting hole locations for: BAYSENS119

2.9 in (73.5 cm)

1.08 in (27.5 mm)

4.68 in (118.9 mm)

1.34 in (34.14 mm)

0.58 in (14.76 mm)

0.31 in (8 mm)

0.12 in (3 mm)

TYP R.07 in
(R1.80 mm)

3.39 in (86 mm)

0.24 in (6.00 mm)

2.62 in (66.5 mm)

Installation - Electrical

SCXG-SVX01H-EN 55

Installation - Electrical

Time Clock Option

Figure 51. Grasslin time clock option

The time clock option has a programmable timer that is factory

wired to the unoccupied input to provide on/off control.The
time clock will not allow the unit to pass through the night
setback/morning warm-up mode, except on units with optional
night heat/morning warm up, or programmable night setback.
See Figure 51, p. 56.

The timeclock, a “Digi 20” by Grasslin, is inside the control

panel, but accessible with the control panel door closed.This
same type timer is also used for programmable night setback/
morning warm up. Programming instructions for the “Digi 20”
timer are in the “Programming” section.

Time Clock Installation

1. Ensure operating temperature is between 4°F and
131°F.

2. Locate the timeclockat least 5 feetaway from any large
electrical contact or machinery to avoid possible
electrical interference problems.

3. Provide a separate independent circuit for the time
clock power supply.

4. Since all electronic instruments are sensitive to
voltage spikes, pay close attention tot he following:

a. If possible, supply power to the electronic time

clock from a phase different than the one
supplying power to the load.

b. Provide a suitableVaristor or RC network across the

INDUCTIVE LOADS supply terminals to reduce
voltage spikes.

c. Place a diode across the DC OPERATED INDUCTOR

terminals to eliminate back EMF.

d. HIGHLY INDUCTIVE LOADS, especially fluorescent

lights, may require a relay in which case step a. and
c. apply.

The time clock can be surface or flush mounted. Lift off the

front cover and loosen the two screws on opposite
corners. Pull off the base’s plug with a left to right rolling
motion.

Time Clock Installation Checklist

1. Ensure operating temperature is 4°F to 131°F.

2. Locate the timeclockat least 5 feetaway from any large
electrical contact or machinery to avoid possible
electrical interference problems.

3. Provide a separate independent circuit for the time
clock power supply.

4. Since all electronic instruments are sensitive to
voltage spikes, pay close attention to the following:

a. If possible, supply power to the electronic time

clock from a phase different than the one supplying
power to the load

b. Provide a suitableVaristor or RC network across the

INDUCTIVE LOADS supply terminals to reduce
voltage spikes.

c. Place a diode across the DC OPERATED INDUCTOR

terminals to eliminate back EMF.

d. HIGHLY INDUCTIVE LOADS, especially fluorescent

lights, may require a relay in which case (A) and (C)
apply.

The Digi 20A time clock unit can be surface or flush

mounted. Lift off the front cover and loosen the two
screws on opposite corners. Pull off the base’s plug with a
left to right rolling motion.

Surface Mounting Inside Panel

Place screws through the base’s preset holes and screw to
back of panel or wall.

Wire according to the instructions in the following section.

Depending upon the specific installation, you may find it
more convenient to complete wiring before attaching the
base.

Place the terminal cover over the terminal block by
aligning the two screws with the corner holes in the base.
Push the timer firmly onto the plug in thebase.Tighten the
two screws. A base for DIN rail mounting is optional.

Wiring theTime Clock

1. Wire 24, 120, or 220 VAC to input terminals. Make sure
to apply correct voltage. Using incorrect voltage will
void the warranty.

2. Connect wire to the screw terminals according to the
unit wiring diagrams. Use 12 to 22 AWG wire.

Remote Human Interface Panel Installation

Human Interface (HI) Panel

The HI enables the user to communicate necessary unit

operating parameters and receive operating status
information from within the occupied space.

56 SCXG-SVX01H-EN

Installation - Electrical

The HI displays top level information in the LCD window,

unless the operator initiates other displays, forthe various
unit functions. It also displays menu readouts in a clear
language 2 line, 40 character format.The 16-key keypad
allows the operator to scrollthrough thevarious menus to
set or modify the operating parameters. See Figure 52,

p. 57 to reference the HI keypad.

Figure 52. Human interface (HI) panel keypad

The run length of the low voltage AC power wiring to the

remote HI must not exceed three (3) ohms/conductor.
Refer to Table 39, p. 57.

Table 38. Maximum communication link wiring length

max. wire length

1,000 ft up to 60 pf/ft
2,000 ft up to 50 pf/ft
3,000 ft up to 40 pf/ft
4,000 ft up to 30 pf/ft
5,000 ft up to 25 pf/ft

Note: pf/ft = picofarads/foot

max. capacitance between

conductors

Ambient Temperature and Humidity Limits

Ambient Operating Conditions

• Temperature: 32 to 120°F

• Relative humidity: 10 to 90%, non-condensing

Ambient Storage Conditions

• Temperatures: -50 to 200°F

• Relative humidity: 5 to 95%, non-condensing

Table 39. Wiring recommendations for the remote HI

distance to remote HI recommended wire size

panel

0-460 feet 18 gauge

461-732 feet 16 gauge

733-1000 feet 14 gauge

Remote Human Interface Panel

The remote human interface (RHI) panel is identical to the

unit mounted HIwith the exceptionof the “unit select” key.

This key allows the operator to switch from one unit to the

next to program or view status information regarding a
particular unit.

The RHI functions the same as the unit mounted HI with

two exceptions.The first is the “test start” function.The
operator can view the service parameters, but can only
initiate the service test function at the unit.The RHI door
has a locking screw to deter access by unauthorized
personnel. Additionally, the RHI can control up to four
different units.

Location Recommendations

The HI microprocessor module is mounted inside a

molded plastic enclosure for surface mounting. It is not
weatherproof.Therefore, it is only applicable for indoor
use.

Locate the RHI panel in an area that will ensure the
communication link between the panel and the unit(s)
does not exceed 5,000 feet maximum or pass between
buildings. See Table 39, p. 57.

Mounting the Remote Human Interface (RHI) Panel

The installer must provide all mounting hardware such as;

hand tools, electrical boxes, conduit, screws, etc. Refer to

Figure 53, p. 59 for the mounting hole and knockout

locations.

Procedure

Refer to Figure 53, p. 59 and follow the procedure below
for mounting the remote HI panel on a 4” by 4” electrical
junction box. Place the microprocessor in a clean dry
location during the enclosure mounting procedures to
prevent damage.

1. Mount an electrical junction box in the wall so that the
front edge of the box will be flush with the finished wall
surface.

2. Prior to mounting the panel, the microprocessor
module

To remove the module:

a. Lay the remote panel face up on a flat surface and

b. Remove the recessed hinge screw from the left

must be carefully removed from the enclosure.

remove the locking screw from the right hand
bottom end of the panel.

hand bottom end of the panel.

SCXG-SVX01H-EN 57

Installation - Electrical

c. Unlatch the door of the enclosure as if to open it,

and slide theleft hand side of the doorupward away
from the hinge. Lay it aside.

d. With the key pad visible, remove the two (2) screws

located on the right hand side of the key pad.

e. Carefully slide the key pad plate upward from the

bottom, releasing the extruded hinge pin from its
socket at the top.

f. Set the microprocessor aside until mounting is

complete.

3. Remove the junction box knockout in the back of the
enclosure.

Note: The top of the enclosure is marked “TOP.”

4. With the enclosure in the correct position; align the
mounting holes around the knockout in the enclosure
with the screw holes in the electrical handy box and
secure with the appropriate screws.

5. Replace the microprocessor within the enclosure as
follows:

a. Verify that the terminal block jumpers are

connected properly.

b. Slide the extruded hinge pin at the top left ofthe key

pad plate into the hole located at the top left hand
side of the enclosure.

c. Slide the bottom of the plate into place, aligning the

two (2) clearance holes with the screw holes on the
right. Install the screws but do not tighten.

Note: If the two screws are not installed as called out in

the previous step, hold against the key pad plate
while installing the door in the next step, to prevent
it from falling out.

d. Slide the extruded hinge pin at the top left of the

door into thehole located under thebottom left side
of the display.

e. Install and tighten the hinge screw located at the

bottom left side of the enclosure.

5. Remove the necessary knockouts for the wire or
conduit entry before mounting the panel.

6. Place the enclosure back onto the surfaceand secure it
with the appropriate screws.

7. Follow step 5 in the previous section, “Mounting on a
4” by 4” Electrical Box,” to replace the microprocessor
within the enclosure.

Wall Mounting the RHI Panel

1. Prior to mounting the panel, the microprocessor
module must be removed from the enclosure.
Complete step 2in the previous discussion,“Mounting
on a 4 in. x 4 in. Electrical Box,” before proceeding.

2. With the microprocessor removed, refer to Figure 53,

p. 59 for the location of the mounting holes to be used

for wall mounting.

3. Place the enclosure against the mounting surface and
mark the mounting holes.

Note: The top of the enclosure is marked with “TOP.”

4. With the enclosure in the correct position, remove the
enclosure and drill the necessary holes in the surface
for the appropriate fasteners, (plastic anchors, molly
bolts, screws, etc.)

58 SCXG-SVX01H-EN

Figure 53. Remote HI mounting holes and knockout locations

Installation - Electrical

Wiring the Remote Human

Interface

Proper Field Wiring and Grounding
Required!

All field wiring MUST be performed by qualified

personnel. Improperly installed and grounded field
wiring poses FIRE and ELECTROCUTION hazards.To
avoid these hazards, you MUST follow requirements for
field wiring installation and grounding as described in
NEC and your local/state electrical codes. Failure to
follow code could result in death or serious injury.

SCXG-SVX01H-EN 59

WARNING

Installation - Electrical

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors.Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect
power and discharge capacitors before servicing could
result in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

The remote human interface requires 24 VAC+4volts

power source and a shielded twisted pair communication
link between the remote panel and the interprocessor
communication bridge (ICPB) module at the self­contained unit.

Field wiring for both the low voltage power and the
shielded twisted pair must meet the following
requirements:

Important: To prevent control malfunctions, do not run

low voltage wiring (30 volts or less) in
conduit with higher voltage circuits.

1. All wiring must be in accordance with NEC and local
codes.

2. Reference Table 39, p. 57 for recommended wiring
distance and size.

3. Communication link wiring must be 18 AWG shielded
twisted pair (Belden 8760, or equivalent).

4. Communication link must not exceed 5,000 feet
maximum for each link. See

5. Do not run communication link between buildings.

Table 38, p. 57.

Low Voltage (AC) Field Wiring Connections

To access the wire entry locations,open the RHIpanel door

and remove the two screws on the right-hand side of the
key pad. Swing the keypad open, exposing both the wire
entries and the back of the HI module. Refer to Figure 53,

p. 59 and connect one end of the three conductor 24 volt

wires to the remote panel terminal strip (+), (-), and
(ground).

Communication Link (Shielded Twisted Pair)

Wiring

Trim the outer covering of the shielded cable back

approximately 1 inch. See Figure 54, p. 60. Do not cut the
bare shield wire off. Strip approximately 1/2-inch of
insulation from each insulated wire to connect them to the
terminal strip at the remote panel.

Connect the white lead to the positive (+) terminal, the
black lead to the negative (-) terminal, and the bare shield
wire to the terminal at the remote human interface panel.

Close the key pad plate. Install and tighten the two screws
removed earlier. Close the outer door and install the
recessed locking screw at the bottom right handside of the
enclosure to prevent accidental starting of the unit by
unauthorized personnel while completing thewiring at the
self-contained unit.

At the Self-Contained Unit

Connect the opposite end of the three conductor 24-volt
wire to the appropriate terminal strip as follows:

Note: Although the 24 volt power is not polarity sensitive,

do not connect either the + (plus) or - (minus)
terminals from the remote panel to ground at the
self-contained unit.

Connect the wire connected to the positive (+) terminal at
the remote panel. Connect the wire connected to the
negative (-) terminal at the remote panel. Connect the
ground wire from the remote panel to the unit control
panel casing.

Figure 54. Dressing shielded twisted wire

60 SCXG-SVX01H-EN

Installation - Electrical

Interprocessor Communication Bridge Module

Wiring

Trim outer covering of shielded cable back approximately

1”.SeeFigure 54, p. 60. Cut bare shield wire even with
outer covering. Strip approximately 1/2” of insulation
from each insulated wire to connect to terminal strip at
unit. Wrap tape around any exposed foil shield and base
shield wire.

Note: The communication link is polarity sensitive.

See unit wiring diagram and connectwhite lead topositive
(+) terminal and black lead to negative (-) terminal. (These
terminals are numbered. Reference to color is for
clarification to maintain polarity).

Note: To maintain polarity,do not connect the base shield

wire to ground at the self-contained unit.

Connecting toTracer Summit

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors.Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect
power and discharge capacitors before servicing could
result in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

IntelliPak commercial self-contained (CSC) units operate
withTrane building automation software,Tracer Summit
version 10.0.4 or later or any OS2 operating system.

Note: Tape non-insulated end of shield on shielded wire

at unit. Any connection between shield and ground
will cause a malfunction. If daisy-chained in unit,
splice and tape shields to prevent contact with
ground.

Communication Wiring

Note: Communicationlink wiring is shielded, twisted pair

of wire and must comply with applicable electrical
codes.

An optional communication link provides a serial

communication interface (SCI) betweenTracer Summit
and each commercial self-contained (CSC) unit in the
system.The CSC system can have a maximum of 12 CSC
units per connection link toTracer Summit. Use a single 18

AWG shielded, twisted pair wire with stranded, thinned

copper conductors to establish each communication link
betweenTracer Summit and each unit.

Programming the Time Clock Option

Setting theTime

Important: Depress the reset key before beginning to

set time and program.

1. Select military (24:00 hr.) or AM/PM (12:00 hr.) time
mode by depressing and holding the “h” key while
pressing “+ 1h” key to toggle between military and

AM/PM. (AM appears in the display when in AM/PM

mode.)

2. Press and hold down “” key.

3. If setting the time when daylight savings time is in
effect, press “+ 1h” key once (+ 1h will appear in
display).

4. Set hour with “h” key. If AM or PM does not appear in
display, the unit is in military time. See note above to
change display.

5. Set minutes with “m” key.

6. Press “Day” key repeatedly to the day of the week. (1
is Monday, 7 is Sunday)

7. Release “” key, colon will begin flashing.

Note: If keys h + or m + are kept depressed for longer than

2 seconds, a rapid advance of figures will result.

The “Digi 20” electronic time switch is freely

programmable for each day of the week in one minute
increments. For easy and quick programming, the
following 4 block programs are available:

• Monday through Sunday

• Monday through Saturday

• Monday through Friday

• Saturday and Sunday

Programming

Follow the instructions below for programming the time
clock.

1. Press “Prog.” key. 1234567 AM—:— will appear in
display. (Pressing “Prog.” key again, display will show
the number of free programs “Fr 20”). Press again to
RETURN to 1st program.

2. Press “”key,“” ON symbol will appear. Pressing
the key again will toggle to OFF “
for the program.

3. Press “h+” to select hour for switching time.

4. Press “m+” to select minute for switching time.

5. If the program is to occur every day of the week, (24
hour time control) ignore “Day” key and press “Prog.”
key to advance to program.

6. For 7 day time control, press “Day” key. 123456
(Monday through Saturday) block of days appears in
display. Pressing “Day” key again,12345(Monday

”. Select ON or OFF

SCXG-SVX01H-EN 61

Installation - Electrical

through Friday) appears in display. Repeated presses
will cycle through all days of the week and back to 1
through 7 (Monday through Sunday). Select day or
block of days desired.

7. Press “Prog.” key and repeat steps 2 through 6a to
enter additional programs of ON and OFF times. (Note
that more than one OFF time may be programmed,
enabling automatic control or manual overrides.)

8. Press “” key to enter run mode.

To review and change programs:

1. To review a program at any time, press “Prog.” key.
Programs display in the sequence they were entered
with repeated presses of “Prog.” key.

2. To change a program, select that program as outlined
in step 1. Enter the time of day and days of week just as
in the programming steps above.The old program is
overwritten with the new selections. Press “Prog.” to
store the new program.

3. To delete an individual program, selectthe program as
in step 1 and press “h” and “m” keys until “—:—”
appears in the display. Press either “Prog.” or “¹” key
until “—:—” flashes.Theprogram is deleted after a few
seconds.

Manual Override

While in the “run” mode (“” symbol is displayed),

pressing the “
load off if it is on, or switch it on if it is off).A hand symbol
appears in the display to indicate the override is active. At
the next scheduled switching time, automatic time control
resumes, eliminating the override.

Pressing the “
display indicating the load is permanently on.

Pressing the “
display indicating the load is permanently off.

Pressing the “

“

” appears in the display.

All days shown in the respective blocks will switch on (or

off) at the selected hour and minute.

” key will reverse the load status (switch

” key a second time “” appears in the

” key a third time “” appears in the

” key a fourth time returns to automatic,

62 SCXG-SVX01H-EN

Operating Principals

Control Sequences of Operation

Occupied/Unoccupied Switching

There are four ways to switch occupied/unoccupied:

1. Night setback zone sensor

2. Field-supplied contact closure (hardwired binary input
to RTM)

3. Tracer Summit

4. Factory-mounted time clock

Field Supplied Occupied/Unoccupied Input on
the RTM

This input accepts a field supplied switch or contacts

closure, such as a time clock, with a rating of 12 mA at 24

VDC minimum.

Tracer Summit System

TheTracer Summit system can control the occupied/

unoccupied status of the self-contained unit.

Factory Mounted Time Clock

A time clock can control the occupied/unoccupied statusof

the self-contained unit.

Unoccupied Sequence of Operation

The unoccupied mode helps conserve energy during

times when a building is usually unoccupied. When in
unoccupied mode, the unit will control to the unoccupied
setpoints (usually a lower heating setpoint and higher
cooling setpoint). Setpoints can be programmed at the HI,

Tracer Summit, or the night setback zone sensor.

The unit enters the unoccupied mode when the RTM

receives a closed signal on the unoccupied input for more
than five seconds. For units with supply air temperature
control entering unoccupied mode, the following
sequence will occur:

• Heating/cooling functions cease and the economizer
option closes fully.The supply fan shuts down for
proper cool-down time of the heat exchanger.
However, the supply fan may remain on for a short
period of time.

• After the supply fan shuts down, the occupied/
unoccupied relay energizes. Also, theVAV box stroke
time begins.The VAV box stroke time is field
adjustable to allow time forVAV boxes to go to the full
open airflow position.

• After the maxVAV box stroke time expires, the supply
fan, economizer (if enabled), compressors, and heat
are enabled to satisfy the unoccupied zone
temperature setpoints.

Note: Unoccupied economizer operation can be enabled

or disabled at the HI or usingTracer Summit.

Figure 55. Typical cycling morning warmup cycle

For units without volume control entering unoccupied
mode, the following sequence will occur:

• The occupied/unoccupied relay energizes and the
economizer option fully closes.

• The fan mode is set to auto and the unit will control to
the unoccupied zone temperature setpoints.

With MWU enabled at the HI, if the zone temperature is

below the MWU setpoint, the unit enters the MWU mode.

MorningWarmup

This feature can be enabled at theHI, and can be used with

factory or field-installed heat. If MWU is not required
disable the function in the setup menu at the HI. MWU
transitions the zone from unoccupied to occupied. It will
heat until the MWU setpoint is met.The unit is then
released to occupied mode. Supply duct static pressure is
maintained during this sequence. MWU can be set (at the
HI) to function as either full or cycling capacity.

Full Capacity Morning Warmup (MWU)

Full capacity morning warmup uses full heating capacity
to heat the zone as quickly as possible. Full heating
capacity is provided until the morning warmup setpoint is
met. At this point, the unit is released to daytime mode.

Cycling Capacity Morning Warmup (MWU)

Cycling capacity morning warmup provides a more
gradual heating to overcome “building sink”as the zone is
heated. Normal zone temperature control with varying
capacity is used toraise the zone temperature to the MWU
zone temperature setpoint.This method of warmup is
used to overcome the “building sink” effect.

See Figure 55, p. 63 for a pictorial explanation of the
cycling MWU sequence. Cycling capacity MWU will heat
until MWU temperature setpoint is reached. Next a 60
minute timer begins. If the buildingload reaches the MWU
ventilation setpoint, or the 60 minutes expire, whichever is
first, the airside economizer will control to the minimum
position. MWU will end when the zone temperature rises
above the MWU terminate setpoint.

SCXG-SVX01H-EN 63

Operating Principals

Timed Override Activation - ICS™

This function is operational whenever the unit’s RTM

module is used as the zone temperature sensor source,
which can be set at the HI panel. When this function is
initiated by the push of the override button on the zone
sensor, the unit will switch to the occupied mode. Unit
operation (occupied mode) during timed override is
terminated by a signal fromTracer.

Timed Override Activation - Non-ICS

This function is active whenever the unit’s RTM module

board is selected as the zone temperature source, which
can be set at the human interface panel. When this
function is initiated by the push of the override button on
the zone sensor, the unit will switch to the occupied mode.

Automatic cancellation of the timed override mode occurs

after three hours of operation.

VAV Drive Max Output

This is a single-pole, double-throw relay rated at a

maximum voltage of 24 vac, two amps max.The relay
contacts of this relay switch when the unit goes from the
occupied mode to the unoccupied mode by means of the
unoccupied binary input, night setback zone sensor, or

Tracer Summit.The contacts will stay switched during the

unoccupied and morning warmup mode.They will return
to the position shown on the unit wiring diagram when the
unit returns to the occupied mode. The intent of this
binary output is to signal the VAV boxes or other terminal
devices to go to a full open airflow position.

Occupied Sequence

All setpoints can be adjusted using the HI panel. Also,

cooling/heating setpoints can be adjusted in the zone, if
using one of the zone sensor options (BAYSENS020,
BAYSENS021, BAYSENS108, BAYSENS110,BAYSENS019,
or BAYSENS074). For a complete list of unit setpoint
default values and ranges, see the IntelliPak Self-

Contained Programming Guide, PKG-SVP01*-EN.

Occupied Zone Temperature - Cooling

The unit transitions from unoccupied to occupied when

the occupied/unoccupied input on the RTM is open for
more than five seconds after having been closed.This
input can be received fromTracer Summit, the remote
NSB zone sensor, the timed override function, or a field
supplied contact. Dependent on unit options and the HI
programming, the following sequence will occur:

• The unit will begin MWU and then switch to the
occupied mode after the MWU setpoint is met.

• Purge will be enabled byTracer Summit.Then Tracer
Summit will enable the occupied mode.

• The unit will switch from unoccupied to occupied
control immediately.

Upon entering occupied mode, the supply fanremains on.

The occupied/unoccupied relay will de-energize.

Zone Temperature Control (Unit Model
NumberDigit9=4or5)

A zone sensor located directly in the space sends input to

the RTM while the CV unit is in occupied cooling mode.

When the unit isin occupied cooling, the RTM controls the

zone temperature within the coolingsetpoint deadband by
modulating the economizer option and/or staging
mechanical cooling on and off as required.

Supply Air Temperature Control (Unit Model
NumberDigit9=1,2,3,or6)

When the VAV unit is in occupied cooling, the RTM

controls the supply air temperature to the specified supply
air cooling setpoint by modulating the economizer option
and/or staging mechanical cooling on and off as required.

The changeover relay contacts (field supplied) must be

open on units with hydronic heat for cooling to operate.

Cooling

Upon entering occupied mode, the RTM receives an input
from either the HI, RHI,TracerSummit, or the GBASto start
the supply fan.The RTM supply fan contacts close and
energize the supply fan contactor. When the supply fan
starts, the fan proving switch closes, signaling the RTM
that airflow is established.The VFD will ramp the fan, and/
or the airside economizer dampers will open to the user­defined minimum position.

When a cooling request is sent to the RTM from the zone

sensor, the RTM evaluates the system operating
conditions using the supply air and outdoor temperature
input before sending the request to the MCM for
mechanical cooling. If outdoor conditions (temperature
and humidity) are suitable or the EWT is within specified
setpoints, the RTM will attempt to use “free cooling”
without using any compressors.The RTM will use either
the airside or watersideeconomizer option. When outdoor
air conditions are not suitable, only mechanical cooling
will function and outside air dampers will remain at their
minimum position. If the unit does not have an
economizer, mechanical cooling will operate to satisfy
cooling requirements.

Units With Economizer

If the entering condenser water temperature (units with a

WSE) or the outside air enthalpy (units with an ASE) is

appropriate to use “free cooling,” the economizer will
attempt to satisfy the cooling zone temperature setpoint.

Note: When using an ASE with economizer enabled, O/A

temperature enable can be used instead of
comparative enthalpy if the O/A temperature falls
below the economizer setpoint.

Then compressors will stage on as necessary to maintain

supply air temperature setpoint, which is user-defined at
the HI. Minimum on/off timing of compressors prevents
rapid cycling.

When both airside and waterside economizers are on a

single unit, priority must be set at the HI.The economizer

64 SCXG-SVX01H-EN

Operating Principals

with the highest priority attempts cooling first. Once it is
operating at its maximum, and if additional cooling is
necessary, the other economizer enables before
mechanical cooling begins.

Cooling/Waterside Economizer

Waterside economizing enables when the unit’s entering

water temperature is below the unit’s entering mixed air
temperature by 4°F plus the user adjustable economizer
approach temperature.The approach temperature default
is 4°F.

Waterside economizing disables when the unit’s entering

water temperature is not below the unit’s entering mixed
air temperature by at leastthe water economizer approach
temperature (default value of 4°F).The economizer acts as
the first stage of cooling. If the economizer is unable to
maintain the zone (CV units) or supply air (VAV units)
temperature setpoint, the compressor module will bring
on compressors as required to meet the setpoint.

Cooling/Airside Economizer

On units with an airside economizer, a call for cooling will
modulate the fresh air dampers open.The rate of
economizer modulation is based on deviation of the zone
temperature from setpoint; i.e., the further away from
setpoint, the faster the fresh air damper willopen.The first
stage of cooling will start after the economizer reaches full
open.

Note: The airside economizer will only function freely if

ambient conditions are below the enthalpy control
settings or below the return air enthalpy if unit has
comparative enthalpy installed. If outside air is not
suitable for “economizing,” the fresh air dampers
drive to the minimum open position. A field
adjustable, factory default setting at the HI panel or

Tracer Summit can provide the input to establish

the minimum damper position.

When outdoor air conditions are above the setpoint or

comparative enthalpy control setting, only mechanical
cooling will function and outside air dampers will remain
at their minimum position.

Mechanical Cooling

If the zone temperature cannot be maintained within the
setpoint deadband using the economizer option or ifthere
is no economizer, the RTM sends a cooling request to the
MCM.The compressor module checks the compressor
protection circuit before closing stage one. After the first
functional stage starts, the compressor module monitors
the saturated refrigerant temperature and closes the
condenser fan output contact when the saturated
refrigerant temperature rises above the lower limit
setpoint.

Air-Cooled Units Only

The compressor module closes the condenser fan output

contact when the saturated refrigerant temperature rises
above the lower limit setpoint.

Water-Cooled Units Only

The WSM modulates the condenser coil water valves to

maintain condenser temperature, if applicable. Otherwise,
it will check the entering condenser water temperature to
ensure it is greater than 54°F or if not, it will lock out
cooling.

Auto Changeover (Units with Heat Only)

When the system modeis in auto, the modewill change to

cooling or heating asnecessary tosatisfy the zone cooling
and heating setpoints.The zone cooling and heating
setpoints can be as close as 2°F (1.1°C).

Occupied Zone Temperature - Heating

Relies on input from a sensor directly in the space, while
a system is in occupied heating mode or an unoccupied
period, to stage electric heat on and off or modulate the
hydronic heating valve as required to maintain the zone
temperature within the heating setpoint deadband.The
supply fan will operate when there is a request for heat.

Electric Heat

On units with electric heat, the zone temperature can be
controlled to a heating setpoint during theoccupied mode
by cycling a single stage electric heater. An interface is
provided for field supplied single stage electric heat.The
zone temperature heating setpoint anddeadband are user
defined at the HI panel.

Hydronic Heat: HotWater or Steam

On units with hot water or steam heating, the zone
temperature can becontrolled to a heatingsetpoint during
the occupied mode.The zone temperature heating
setpoint and deadband are user defined at the HI panel or
zone sensor. VAV occupied heating initiates by closing a
field-supplied switch or relay contacts connected to the
changeoverinput on theRTM. Supply air static pressure is
maintained.

Supply Air Setpoint Reset (VAV Units Only)

Supply air reset can be used to adjust the supply air
temperature setpoint onthe basis of a zone temperature or
outdoor air temperature. Supply air reset adjustment is
available at the HI panel for supply air heating and supply
air cooling control.

Reset based on outdoor air temperature

Outdoor air cooling reset is sometimes used in
applications where the outdoor temperature has a large
effect on building load. When the outside air temperature
is low and the building cooling load is low, the supply air
setpoint can be raised, thereby preventing subcooling of
critical zones.This reset can lower usage of mechanical
cooling, thus savings in compressor kW, but an increase in
supply fan kW may occur.

Outdoor air heating reset is the inverse of cooling, with the
same principles applied.

SCXG-SVX01H-EN 65

Operating Principals

For both outdoor air cooling reset and heating reset, there
are three user defined parameters that are adjustable
through the human interface panel.

• Beginning reset temperature

• Ending reset temperature

• Maximum amount of temperature reset

Reset based on zone temperature

Zone reset is applied to the zone(s)in a building that tends
to overcool or overheat.The supply air temperature
setpoint is adjusted based on the temperature of the
critical zone(s).This can have the effect of improving
comfort and/or lowering energy usage.The user-defined
parameters are the same as for outdoor air reset.

Supply Air Tempering
(Hot Water and Steam VAV Units Only)

When supply air temperature falls below the supply air

temperature deadband low end, the heating valve
modulates open to maintain the minimum supply air
temperature setpoint.

DaytimeWarmup(Units with Supply Air

Temperature Control Only)

During occupied mode, if the zone temperature falls to a
preset, user-defined zone low limit temperature setpoint,
the unit is put into daytime warmup.The system changes
over to CV heating, the VAV boxes drive full open.
However, unit airflow modulation control operates to
maintain duct static setpoint, and full heating capacity is
provided until the daytime warmup setpoint is reached.

The unit is then returned to normal occupied mode.

Supply Air Tempering

Supply air tempering is available on units without volume
control and with hot water, steam, or electric heat or units
with supply air temperature control with steam or electric
heat. When the unit is in heat mode but not actively
heating, if thesupply air temperaturedrops to 10°F (5.5°C)
below the occupied zone heating temperature setpoint,
electric heat will stage on or the hydronic valve will
modulate to maintain a minimum supply air temperature.

The unit transitions out of heat mode if the supply air

temperature rises to 10°F (5.5°C) above the occupied zone
heating temperature setpoint.

Changeover

This mode only functions on units with supply air

temperature control with hydronic heat. When the
changeover binary input is closed the unit will control to a
discharge air heating setpoint.This setpoint is entered
from the HI, and can be a higher temperature than the
supply air cooling setpoint.This function maintains duct
static pressure.

Thermostatic ExpansionValve

NOTICE:

Compressor Damage!

Systems operating with lower superheat than
recommended could cause serious damage to the
compressor.

Refrigerant system reliability and performance is heavily
dependent upon proper superheat.The importance of
maintaining the proper superheat cannot be
overemphasized. Accurate measurements of superheat
will provide the following information:

• How well expansion valve is controlling refrigerant
flow.

• Efficiency of the evaporator coil.

• Amount of protection compressor is receiving against
flooding.

The expected range for superheat is 14-20°F at full load

conditions. At part load, expect a properly adjusted
expansion valve to control to 8-12°F superheat. Systems
operating with lower superheat could cause serious
compressor damage due to refrigerant floodback.

Compressors

Units use two compressors of 10 and 15 hp.When viewing
the front of the unit, compressors are identified A and B
from left to right.The second compressor from the left, or
B compressor, is always the first to comeon, unless locked
out for a malfunction or shut off on frost protection. Refer
to Table 40, p. 67 for compressor cycling stages and

Table 1, p. 11 for percent cooling capacity by stage.

The control system logic permits compressor operation

only after the supply fanis on. If the supply fanshuts down,
compressors will not operate. Units without head
pressure control (units with intermediate piping packages)
will lock out mechanical cooling when the entering
condenser water temperaturefalls below 54°F. Mechanical
cooling will resume when the entering condenser water
temperature exceeds 58°F.

Compressor Cycling

Compressors cycle to maintain the operating state
required by the temperature controls. In the event of a
compressor failure, the next available compressor turns
on. Refer to Table 40, p. 67 for compressor cycling by unit
model and tons.

During normal conditions, compressors will not shut off
until they have been on for at least three minutes and will
not turn on until they have been off for at least three
minutes. Normal operating conditions are established on
an individual compressor basis. When a compressor
starts, its timer also starts.The compressor evaporator

66 SCXG-SVX01H-EN

Operating Principals

circuit frost protection can override the “minimum” timer
and reduce the five minute minimum required time
period.

When the unit is powered up, or manually reset there will

be a three to eight minute delay before the first
compressor may be turned on as requested by the unit
temperature control algorithm.

Compressor Lead/Lag Operation

Compressor lead/lag is a user-selectable feature at the HI
panel and is available on all units. After each request for
compressor operation, the lead refrigeration circuit or
compressor switches, thereby causinga more equitable or
balanced run time among compressors.

When lead/lag is enabled, each time the system cycles, it

will alternate between the standard compressor staging
and the lead/lag staging. Using Table 40, p. 67, a SXWG
30-ton unit will first stage compressor B then A, then AB
for first cycle and A, then AB for the second cycle.

Appropriate condenser valves (water-cooled and

condenser fans (air-cooled) will stage with appropriate
compressors to maintain saturated condensing
temperature. Enabling lead/lag may drop a cooling stage
when compared to standard staging. See Table 40, p. 67
for compressor staging.

Step Control

Steps of mechanical cooling are control based on supply
air or zone temperature. See Table 40, p. 67 for
compressor staging.

Capacity is based on an integrating control concept.The
unit capacity matches the existing load and maintains an
average supply air temperature within the supply air
setpoint temperature control band region.

The supply air temperature control band is centered

around supply air temperature setpoint and is adjustable

Table 40. Compressor stages.

Compressor HP

by Stage

Compressor

Unit Size

SXWG 20, 25

SXRG 20

SXWG 30

SXRG 25

SXWG 35

SXRG 32

Refrigerant
Circuit Type

Model # Digit 5

Independent 10 10 B/AB A/AB MCM

Independent 15 10 B/A/AB A/AB MCM

Independent 15 15 B/AB A/AB MCM

from 2 to 12°F. In a steady state, the unit will either
maintain a constant level of cooling capacity with the
supply air temperature within the control band, or the
highest active cooling level will cycle to provide an
average supply air temperature equal to the setpoint.

If the supply air temperature swings outside the limits of
the control band, the mechanical cooling capacity will
increase or decrease by one level accordingly.The change
occurs by integrating the temperature offset from the
control band limit.

A minimum time delay of five minutes follows each

change in cooling level.This time delay promotes stability
by allowing the system to respond to the change before
any further control action occurs. As the supply air
temperature approaches setpoint, the time duration
between changing levels of cooling capacity increases.

See Figure 56, p. 68 for the typical unit operating curve.

Figure 57, p. 68 shows typical unit performance when

supply air temperature swings exceed the control band
limits.

Adjust the supply air temperature control band according

to the desired unit performance. Increasing the control
band reduces the equipment cycle rate and increases the
maximum potential supply air temperaturedeviation from
setpoint. Conversely, decreasing the control band reduces
the maximum potential temperature deviation, but
increases the compressor cycle rate.

Follow these recommendations concerning the supply air
temperature control band settings based on expectedunit
sizing:

2 Cooling stage unit: 9°F

3 Cooling stage unit: 7°F

4 Cooling stage unit: 6°F

Standard

Staging

Lead/Lag

Compressor

Staging

SCM

or

MCMAB

SCXG-SVX01H-EN 67

Operating Principals

Figure 56. Typical pulldown curve for unit operating properly within control band

Figure 57. Typical pulldown curve for unit operating improperly outside control band

Compressor Safety Devices

If a compressor low pressure cutout opens during
compressor start-up, the UCM will not shut the
compressor off during the first two to three minutes after
start-up.This prevents possible nuisance trips during low
ambient start conditions. SeeTable 41.

Table 41. Pressure cutouts (open/close)

Unit Model

SXWF 553/424 49/74

SXRF 650/500 36/61

High Pressure

Cutout

Low Pressure

Cutout

Eachcompressor’sdischarge line contains a highpressure
cutout. Under abnormal operating conditions, the cutout
will open to stop compressor operation.

Low Ambient Compressor Lockout

This function willlockout the compressorif the outdoorair

temperature sensor reads an outdoor temperature below
the low ambient compressor lockout temperature
setpoint.This setpoint is adjustable at thehuman interface
panel. Compressors will lock out when outdoor air
temperature falls belowthat selected temperature and will
start again when the temperature rises 5°F above the
setpoint.

Evaporator Coil Frost Protection FROSTAT™

The FROSTAT™ system eliminates the need for hot gas

bypass. It utilizes an evaporator temperature sensor
mounted on the suction line near theTXV bulb of each
circuit to protect the evaporator from freezing.

If the evaporator temperature approaches the specified
setpoint (adjustable between 25 and 35°F at the HI) the
compressor(s) will cycle off.The supply fan remains on to
help de-ice the coil.The compressors will restart when the
evaporator temperature hasrisen 10°F above the specified
cutout temperature and when the compressor(s) have
been off a minimum of three minutes.This prevents rapid
cycling of the compressors.

Service Valve Option

If ordered, service valves are factory installed on each
circuit before and after the compressor to allow
compressor isolation for servicing.Waterside
Components.

Waterside Components

Waterside components consist of water piping, water

valves, water flowswitchoption, water cooled condensers
(SXWG only), and the economizer option.

68 SCXG-SVX01H-EN

Operating Principals

Water Purge

NOTICE:

Proper WaterTreatment!

The use of untreated or improperly treated water could

result in scaling, erosion, corrosion, algae or slime. It is
recommended that the services of a qualified water
treatment specialist be engaged to determine what
water treatment, if any, is required.Trane assumes no
responsibility for equipment failures which result from
untreated or improperly treated water, or saline or
brackish water.

This user-definable feature allows the user to select a

purge schedule to automatically circulate water through
the economizer and condensers periodically during non­operational times.This allows fresh chemicals to circulate
in waterside heat exchangers.This feature is on all units
and is defined at the HI.

Water Piping Options

Water piping is factory-installed with left-hand

connections on units without a waterside economizer.
Units can be ordered with either basic piping or
intermediate piping. Also, units with waterside
economizers can be set for either variable or constant
water flow at the HI. SeeFigure 58, p. 70 and Figure 59,

p. 70 for detailed piping configuration information.

With compatible piping configurations, the unit can be

configured to provide:

1. Constant water flow with basic or intermediate piping
or

2. Variable water flow (head pressure control) with
intermediate piping only.

Constant water flow is for condenser pumping systems
that are not capable of unloading the water-pumping
system. Variable water flow maximizes energy saving by
unloading the water pumping system.

Basic Water Piping

This option is available on units without a waterside

economizer and with condenser water applications above
54°F (12.2°C) that do not require condensing pressure
control. Left hand water connections and piping are
extended to the unit exterior. Manifold piping is factory
installed.

Intermediate Water Piping

This option provides condensing temperature control

when the unit is configured (user defined at the HI) for
variable water flow with or without a waterside
economizer. A two-way modulating control valve is wired
and installed in the unit to maintains a specific range of
water temperature rise through the condenser when
entering fluid temperature is less than 58°F (15°C).This
option allows the compressor to operate with entering
fluid temperature down to 35°F (2°C).The minimum valve

position to maintain minimum condenser flow rates is
user-defined at the HI.This valve drives closed if the unit
shuts down or if a power failure occurs.

Water Flow Switch Option

A water flow switch is factory installed in the condenser

water pipe within the unit. Whenever the flow switch
detects a water flow loss prior to or during mechanical
cooling, compressor operation locks out and a diagnostic
code displays. If water flow is restored, the compressor
operation automatically restores.

Water-Cooled Condensers

Units that are set up for variable water flow will modulate
a water valve to maintain a user-defined condensing
temperature setpoint. Condensing temperature will be
referenced utilizing factory installed sensors located at
each condenser.

Table 42. Condenser water piping connection sizes

Unit Size Inlet Pipe Outlet Pipe

SXWG 20, 25, 30, 32, 35 2 1/2 NPT 2 1/2 NPT

Waterside Economizer Option

The waterside economizer option takes advantage of

cooling tower water to either precoolthe entering airto aid
the mechanical cooling process or, if the water
temperature is low enough, provide total system cooling.

Waterside economizing enables when the unit’s entering

water temperature is below the unit’s entering mixed air
temperature by a minimum of 4°F plus the economizer’s
approach temperature.The approach temperature default
is 4°F. Waterside economizing disables when the unit’s
entering water temperature is not below the unit’s
entering mixed air temperature by at least the water
economizer approach temperature.The approach
temperature defaults to 4°F.The economizer acts as the
first stage of cooling. If the economizer is unable to
maintain the supply air setpoint, the unit control module
brings on compressors as required to meet the setpoint.

The waterside economizer includes a coil, modulating

valves, controls, and piping with cleanouts.The coil
construction is ½-inch (13 mm) OD seamless copper tubes
expanded into aluminum fins.The evaporator and
economizer coils share a common sloped (IAQ) drain pan.
Drain pan options are either galvanized or stainless steel,
and are insulated and internally trapped.

The waterside economizer coil is available with either a

two or four row coil, with no more than 12 fins per inch.

The tubes are arranged in a staggered pattern to maximize

heat transfer.The coil has round copper supply and return
headers with removable cleanout and vent plugs.The
optional mechanical cleanable economizer hasremovable
cast iron headers to allow easy mechanical cleaning of the
tubes.The waterside working pressure is rated for 400
psig (2758 kPa).

SCXG-SVX01H-EN 69

Operating Principals

Waterside Economizer Flow Control

Units equipped with a waterside economizer can be set
from the human interface panel for variable or constant
water flow.

Constant Water Flow

Two-way modulating control shutoff valves are wired,

controlled, and installed in theunit. One valve islocated in
the economizer’s water inlet, and the other is in the
condenser bypass water inlet. When the waterside
economizer enables, the two-way valves modulate to
maintain the discharge air temperature setpoint. As the
economizer valve opens, the condenser bypass valve
closes, and vice versa. Full water flow is always
maintained through thecondensers. Both valveswill close
in the event of a power failure.

VariableWater Flow

Two-way modulating control shutoff valves are wired,

controlled, and installed in theunit. One valve islocated in
the economizer’s water inlet, and the other is in the
condenser water inlet. When the economizer valve is
active, the condenser bypass valve closes.The
economizer valve modulates, thus water flow through the
unit modulates. If the water is cool enough for
economizing, but mechanical cooling is also required, the
economizer valve fully opens to establish full water flow
through the condensers.Whenever the water is too warm
for economizing and there is a call for cooling, the
economizer valve fully closes and the bypass valve fully
opens, establishing full water flow through the
condensers. Full water flow is always maintained through
the condensers whenmechanicalcooling is required. Both
valves close whenever cooling is not required, and in the
event of a power failure.

Figure 58. Intermediate piping with waterside economizer, variable or constant water flow

Condenser 1

Economizer

V1

V2

Condenser 2

Figure 59. Intermediate water piping, variable water flow (L) and basic water piping, constant water flow (R)

Condenser 1

Condenser 2

V2

70 SCXG-SVX01H-EN

Condenser 1

Condenser 2

Operating Principals

Unit Airside Components

The unit’s air delivery system consists of dampers,

enthalpy switch option, airside economizer option, filters,
low ambient sensors, and factory mounted single or
double wall plenums.

Supply Air Fan

The unit has a single supply fan that runs at a constant

speed. However, the fan may have the VFD option that
modulates airflow based on supply air temperature
control. Pressing the stopkey onthe HI will turn the supply
fan off.The fan is on continuously when a CV unit is in
occupied mode and except when a unit is in the night heat/
morning warmup mode. During the nightheat and setback
mode the fan cycles on and off in response to a call for
heat.

Low Entering Air Temperature Sensor

This is standard on all units with a hydronic coil or

waterside economizer. It can also be ordered as an option.

A thermostat limit switch is factory mounted on the unit’s

entering air side with a capillarytube serpentine across the
coil face. If the temperature falls below 35°F (2°C), the fan
shuts down and the waterside economizer and/or

hydronic heat valve options open to allow full water flow.
The heat outputalso energizes.A manual resetis required.
The low entering air temperature setpoint is adjustable at

the HI.

High Duct Temperature Thermostat

A factory-supplied temperature limit switch with reset

element detects the supply air duct temperature.This

sensor should be field-installed downstream from the

unit’s discharge in the supply air duct.If the supply air duct

temperature exceeds 240°F (115.6°C), the unit shuts down

and displays adiagnostic. A manual reset is requiredat the

unit.The high duct temperature can be adjusted at the

thermostat.

Dirty Filter Sensor Option

A factory installed pressure switch senses the pressure

differential across the filters. When the differential

pressure exceeds 0.9-inches (23 mm) WG, contact closure

occurs and the HI will display a diagnostic.The unit will

continue to run until you replace the air filters.

A field installed indicator device may be wired to relay

terminals to indicate when filter service is required.

Contacts are rated at 115 VAC and are powered by a field

supplied transformer.

Low Ambient Sensor (Air-Cooled Units)

The low ambient sensor is field-installed on air-cooled

units. Position it in a location subject to ambient

temperatures only and not exposed to direct sunlight or

exhaust fans.

The low pressure cutout initiates based on the ambient

temperature. A time delay on the low pressure cutout

initiates for ambient temperatures between 50 (zero
minutes) and 0°F (10 minutes).This helps to prevent
nuisance low pressure cutout trips.

Supply Air Static Pressure Limit

The opening of the VAV boxes coordinate during unit

startup and transition to/from occupied/unoccupied
modes to prevent supply air duct over pressurization.
However,if for any reason the supply air pressure exceeds
the user-defined supply air static pressure limit set at the
HI panel, the supply fan VFD shuts down.The unit will
attempt to restart, up to three times. If the over
pressurization condition still occurs on the third restart,
the unit shuts down and a manual reset diagnostic sets
and displays at the HI.

Variable Frequency Drive Option

The variable frequency drive (VFD) is driven by a

modulating 0-10 vdc signal from the RTM module. A
pressure transducer measures duct static pressure, and
the VFD adjusts the fan speed to maintain the supply air
static pressure within an adjustable user-defined range.

The range is determined by the supply air pressure

setpoint and supply air pressure deadband, which are set
at the HI panel.

VFDs provide supply fan motor speed modulation.The

drives will accelerate or decelerateas required to maintain
the supply air static pressure setpoint.

VFD with Bypass

Bypass control is an option that provides full nominal
airflow in the event of drive failure.The user must initiate
the bypass mode at the HI panel. When in bypass mode,

VAV boxes need to be fully open.The self-contained unit

will control heating and cooling functions to maintain
setpoint from a user-defined zone sensor. Supply air static
pressure limit is active in this mode.

For more detailed information on VFD operation,
reference the VFD technical manual that ships with the
unit.

Airside Economizer Option

Units with the airside economizer option are equipped
with the necessarycontrol sequences to useoutside air for
the first stage of cooling, in occupied or unoccupied mode
and when ambient conditions are favorable for
economizing. Inherent in the unit controller isthe ability to
suppress the setpoint below the normal unit setpoint.This
allows the building to improve comfort levels when
possible, and at the same time, optimize building
mechanical cooling operation for peak operating
efficiency. An outside air temperature and relative
humidity sensor are provided to allow monitoring of
reference enthalpy and are field installed.

If the unit has the ECEM board, economizer operation
enables when the outside air enthalpy is less than 25
BTU’s/lb. default (adjustable 19-28 BTU’s/lb). During
occupied mode, the outside air damper opens to 15%

SCXG-SVX01H-EN 71

Operating Principals

(adjustable 0-100% at the HI) for ventilation purposes.

Also, the ability to alter the outside air damper position to

compensate for VAV supply air modulation is inherent in

the unit controls, and can be enabled by the operator.

If the unit does not have an ECEM board, it will economize

when the O/A temperature falls below the O/A economizer

setpoint.

The mixing box fabrication is galvanized steel. Opposed

low leak damper blades are fabricated from galvanized

steel and rotate on rustproof nylon bushings. A factory

installed 24V modulating spring return actuator controls

both damper positions.

When outdoor conditions are not suitable for economizer

cooling, the enthalpy control disables the economizer

function and permits the outdoor air damper to open only

to the minimum position.

On water-cooled units, compressor operation lockout will

not occur at low ambient air temperatures. However,

lockout will still occur via low condenser water

temperature.

The outdoor air dampers drive fully closed whenever the

supply air fan is off, provided there is power to the unit.

Comparative Enthalpy Control

Comparative enthalpy controls the economizer operation

and measures temperatureand humidity of bothreturn air

and outside air to determine which source has lower

enthalpy.This allows true comparison of outdoor air and

return air enthalpy by measurement of outdoor air and

return air temperaturesand humidities.A factory-installed

control board, with field-installed outside and return air

temperature and relative humidity sensors, allows

monitoring of outside and return air.

Note: If comparative enthalpy is not ordered, the

standard method is to compare outdoor air
enthalpy with the fixed reference enthalpy.The
reference enthalpy is set through the human
interface panel.

Units with comparative enthalpy control are equipped

with the necessary control sequences to allow using

outside air for the first stage of cooling, in occupied or

unoccupied mode and when ambient conditions are

favorable for economizing. Inherent in the unit controller

is the ability to suppress the setpoint below the normal

unit setpoint.This allows the building to improve comfort

levels when possible, and at the same time, optimize

building mechanical cooling operation for peak operating

efficiency.

Economizer operation enables when the outside air

enthalpy is 3 BTu/lb less than the return air enthalpy.

During occupied mode, the outside air damper opens to

15% (adjustable 0-100%) for ventilation purposes. Also,

the ability to alter the outside air damper position to

compensate for VAV supply air modulation is inherent in

the unit controls, and can be enabled by the operator.

The mixing box fabrication is galvanized steel. Opposed

low leak damper blades are fabricated from galvanized
steel and rotate on rustproof nylon bushings. A factory
installed 24V modulating spring return actuator controls
both damper positions.

Airside Economizers withTraq™ Damper

Outside air enters the unit through theTraq damper
assembly and ismeasured by velocitypressure flow rings.

The velocity pressure flow rings are connected to a

pressure transducer/solenoid assembly, which
compensates for temperature swings that could affect the
transducer.The ventilation control module (VCM) utilizes
the velocity pressure input, the RTM outdoor air
temperature input, and the minimum outside air cfm
setpoint to modify the volume (cfm) of fresh air entering
the unit as the measured airflow deviates from setpoint.

When the optional preheat temperature sensor is installed

at the auxiliary temperature on the VCM and the preheat
function is enabled, the sensor will monitor the combined
(averaged) fresh air and return air temperatures. As this
mixed air temperature falls below the preheat actuate
temperature setpoint, the VCM activates the preheat
binary output to control a field-installedheater.The output
deactivates when the temperature rises 5°F above the
preheat actuate temperature setpoint.

Using a field-installed CO
as the CO

concentration increases above the CO2reset

2

sensor with CO2reset enabled,

2

start value, theVCM modifies the minimum outsideair cfm
setpoint to increase the amount of fresh air entering the
unit.The setpoint adjusts upward until reaching the CO
maximum reset value.The maximum effective (reset)
setpoint value for fresh air is limited to the system’s
operating cfm. As the CO

concentration decreases, the

2

effective (reset) setpoint value adjusts downward toward
the minimum outsideair cfm setpoint. SeeFigure 60, p. 73
for an airflow cfm vs. CO

concentration curve.

2

StandardTwo-Position Damper Interface

Units with the two-position damper interface are provided
with a 0-10 VDC control output suitable for controlling a
field-provided modulating actuator.In occupied mode, the
output drives to the maximum position.

Airside Economizer Interface

Units with airside economizer interface are equipped with
the necessary control sequences to allow using outside air
for the first stage of cooling, in occupied or unoccupied
mode and when ambient conditions are favorable for
economizing. Inherent in the unit controller isthe ability to
suppress the setpoint below the normal unit setpoint.This
allows the building to improve comfort levels when
possible, and at the same time, optimize building
mechanical cooling operation for peak operating
efficiency. An outside air temperature and relative
humidity sensor are provided for field installation to
monitor reference enthalpy. Economizer operation
enables when the outside air enthalpy is less than 25 BTu/

2

72 SCXG-SVX01H-EN

Operating Principals

lb (adjustable 19-28 BTu/lb.). During occupied mode, the

outside air damper opens to 15% (adjustable 0-100%) for

ventilation purposes. Also, the ability to alter the outside

air damper position to compensate for VAV supply air

modulation is inherent in the unit controls, and can be

enabled by the operator. An analog 2-10VDC output

(adjustable (0-10 VDC) is provided to modulate the field-

provided 30 second damper actuators (adjustable 1-255

seconds).

Airside Economizer Interface with

Comparative Enthalpy

Units with airside economizer interface and comparative

enthalpy are equipped with the necessary control

sequences to allow using outside air for the first stage of

cooling, in occupied or unoccupied mode and when

ambient conditions are favorable for economizing.

Inherent in the unit controller is the ability to suppress the

setpoint below the normal unit setpoint.This allows the

building to improve comfort levels when possible, and at

the same time, optimize building mechanical cooling

operation for peak operating efficiency.A factory-installed

control board, withoutside and return airtemperature and

relative humidity sensors, are provided for monitoring

outside and return air.The sensors are field installed.

Figure 60. CO

reset function, outside air vs. CO

2

2

Economizer operation enables when the outside air
enthalpy is 3 BTU’s/lb. less than the return air enthalpy.
During occupied mode, the outside air damper opens to
15% (adjustable 0-100%) for ventilation purposes. Also,
the ability to alter the outside air damper position to
compensate for VAV supply air modulation is inherent in
the unit controls, and can be enabled by the operator. An
analog 2-10VDC output (adjustable (0-10 VDC) is provided
to modulate the field-provided 30-second damper
actuators (adjustable 1-255 seconds).

Air-Cooled Condensers

Model SXRG units are designed for use with the remote
air-cooled condenser, model CXRC.For more information,
see the air-cooled condenser Installation, Owner, and
Diagnostic Manual, CXRC-SVX01*-EN.

Verify head pressure control, standard or optional.

Condenser fans will stage per a user-defined setting. If the
condenser is equipped with head pressure control (air
modulation on last stage of condenser capacity), the
condenser airflow will modulate to maintain condensing
temperature setpoint. Condensing temperature is
determined by sensors located at each condenser coil.

Maximum
Airflow

Increasing
Reset Amount

O.A CFM
Setpoint

Carbon Dioxide
Reset Start

Increasing
Concentration

Carbon Dioxide
Maximum Reset

SCXG-SVX01H-EN 73

Controls

Points List

RTM Module

Binary Inputs

• Emergency stop

• External auto/stop

• Unoccupied/occupied

• Dirty filter

• VAV changeover with hydronic heat

Binary outputs

• VAV box drive max (VAV units only)

• CV unoccupied mode indicator (CV units only)

• Alarm

• Fan run request

• Water pump request (water-cooled only)

Analog input

• Airside economizer damper minimum position

Analog output

• Outside air damper actuator

Heat Module:

• Analog output

GBAS Module

Binary inputs

• Demand limit contacts

Binary outputs

• Dirty filter relay

• Refrigeration fail relay

• Heat fail relay

• Supply fan fail relay

• Active diagnostics

Analog inputs

• Occupied zone cooling setpoint

• Occupied zone heating setpoint

• Unoccupied zone cooling setpoint

• Unoccupied zone heating setpoint or minimum
outside air flow setpoint

• Supply air cooling setpoint

• Supply air heating setpoint

• Supply air static pressure setpoint

ECEM Module

Analog inputs

• Return air temperature

• Return air humidity

In addition, units with a VOM have:

Binary inputs

• VOM mode A, unit off

• VOM mode B, pressurize

• VOM mode C, exhaust

• VOM mode D, purge

• VOM mode E, purge w/duct pressure control

Binary output

• V.O. relay

Tracer™ LCI-I Module

Constant Volume (CV) Points

Binary inputs

• Airside economizer enable/disable

• Condenser type (air or water cooled)

• Condenser water flow status

• Emergency shutdown

• Local fan switch enable/disable

• Mechanical cooling lockout

• Mechanical heating lockout

• Mixed air temperature

• Occupancy

• Occupancy override

• Occupancy sensor

Binary outputs

• Airside economizer status

• Alarm status

• Compressor on/off status

Controls

• Condenser circuit information

• Condenser water pump status

• Waterside economizer status

Analog inputs

• Airside economizer dry bulb setpoint

• Airside economizer minimum setpoint

• Building static pressure input

74 SCXG-SVX01H-EN

Controls

• Maintenance required time

• Occupancy bypass time

• Outdoor air damper minimum position setpoint

• Outdoor air relative humidity

• Outdoor air temperature

• Unit start delay time setpoint

• Zone temperature

• Zone temperature setpoint

• Zone temperature setpoint (default)

• Zone temperature setpoint limits

• Zone temperature setpoint offsets

• Zone temperature setpoint shift

Analog outputs

• Alarm message

• Building static pressure status

• Condenser saturated refrigerant temperature

• Condenser water temperature

• Cooling output status

• Effective occupancy

• Exhaust fan status

• Heating output status

• Heating/cooling mode

• Morning warm up sensor temperature

• Outdoor air damper position

• Outdoor air enthalpy

• Outdoor air relative humidity

• Return air temperature

• Supply air temperature

• Supply fan status

• Unit status mode

• Zone CO

• Zone relative humidity

2

Variable Air Volume (VAV) Points

Binary inputs

• Airside economizer enable/disable

• Condenser water flow input

• Emergency override

• Local fan switch enable/disable

• Mechanical cooling lockout

• Mechanical heating lockout

• Occupancy

• Alarm status

• Compressor on/off status

• Condenser circuit information

• Condenser type (water or air cooled)

• Condenser waterflow status

• Condenser water pump status

Analog inputs

• Airside economizer dry bulb setpoint

• Airside economizer minimum position

• Building static pressure input

• Building static pressure setpoint

• Daytime warm up setpoint

• Daytime warm up terminate setpoint

• Maintenance required time

• Occupancy bypass time

• Outdoor air damp min position setpoint

• Outdoor airflow minimum setpoint

• Outdoor air relative humidity

• Outdoor air temperature

• Supply air cooling setpoint

• Supply air cooling setpoint (default)

Analog outputs

• Building static pressure status

• Alarm message

• Condenser saturated refrigerant temp.

• Condenser water temperature

• Condenser water temp (local)

• Cooling output status

• Exhaust fan status

• Heating output status

• Heating/cooling mode

• Mixed air temperature

• Morning warm up sensor temperature

• Outdoor air damper position

• Outdoor air enthalpy

• Outdoor air flow

• Outdoor air relative humidity status

• Outdoor air temperature status

• Return air temperature

Binary outputs

• Airside economizer status

SCXG-SVX01H-EN 75

Controls

BCI-Points List

Refer to ACC-SVP*-EN

Phase Monitor

Unit is equipped with phase monitor in control box.The
phase monitor will protect against phase loss, imbalance
and reversal of line voltage. If a fault occurs, the red LED
will energize. While the fault condition is present, the
phase monitor interrupts the 115V control circuit. If no
faults are observed, a green LED will be energized.

Unit Control Components

The Modular Series IntelliPak self-contained unit is

controlled by a microelectronic control system that
consists of a network of modules.These modules are
referred to as unit control modules (UCM). In this manual,
the acronym UCM refers to the entire control system
network.

These modules perform specific unit functions using

proportional/integral control algorithms.They are
mounted in the unit control panel and are factory wired to
their respective internal components. Each module
receives and interprets information from other unit
modules, sensors, remote panels, and customer binary
contacts to satisfy the applicable request; i.e.,
economizing, mechanical cooling, heating, ventilation.

Following is a detailed description of each module’s
function.

RTM Module Board - Standard on all Units

The RTM responds to cooling, heating, and ventilation

requests by energizing the proper unit components based
on information received from other unit modules, sensors,
remote panels, and customer supplied binary inputs. It
initiates supply fan, exhaust fan, exhaust damper,variable
frequency drive output, and airside economizer operation
based on that information.

Reference the RTM points list.

Note: Emergency stop and external auto/stop, stop the

unit immediately, emergency stop generates a
manual reset diagnostic that must be reset at the
unit human interface. External auto-stop will return
the unit to the current operating mode when the
input is closed, so this input is auto reset.

RTM Remote Economizer Minimum Position

The remote minimum position potentiometer,

BAYSTAT023A, provides a variable resistance (0-270
ohms) to adjust the economizer minimum position from 0
to 100% when connected to the economizer remote
minimum position input of the RTM. The RTM must be
selected as the source for economizer minimum position.
If the RTM is the selected source for economizer minimum
position, and if a valid resistance per Table 43, p. 76 is

provided to the RTM remote minimum position input, the
OA cfm compensation function will not operate, even if
enabled. “Default” is the only possible source for
economizer minimum position when using the OA cfm
compensation function.

Table 43. Economizer remote minimum position input

(a) A resistance greater than 350 ohms is assumed to be an open

resistance

Input resistance Economizer min. position

0 - 30 ohms 0 %

30 - 240 ohms 0-100 % (linear)

240 - 350 ohms 100 %

> 350 ohms N/A

circuit. The system will use the default minimum position value.

(a)

RTM Analog Outputs

The RTM has two 0-10 vdc outputs: one for the supply fan

and one for the economizer option.These outputs provide
a signal for one or two damper actuators.There are no
terminal strip locations associated with these wires.They
go directly from pins on RTM circuit board to actuator
motor.

RTM Binary Outputs

The RTM has an output with pressure switch proving

inputs for the supply fan. There is a 40 second delay from
when the RTM starts the supply fan until the fan proving
input must close.A fanfailure diagnostic willoccur after 40
seconds.This is a manual reset diagnostic, andall heating,
cooling, and economizer functions will shut down. If this
proving input is jumped, other nuisance diagnostics will
occur. If the proving input fails to close in 40 seconds, the
economizer cycles to the minimum position.This is a
manual reset diagnostic. External control of the fan is not
recommended.

VAV Drive Max Output

This is a single-pole, double-throw relay rated at a

maximum voltage of 24 vac, two amps.The relay contacts
of this relay switch when the unit goes from the occupied
mode to the unoccupied mode by means of the occupied
binary input. The contacts will stay switched during the
unoccupied and morning warmup mode.They will return
to the position shown on the unit wiring diagram when the
unit returns to the occupied mode.This binary output
signals theVAV boxes or other terminal devices to go full
open.

RTM Alarm Relay

This is a single pole, double throw relay rated at a

maximum voltage of 24 vac, two amps max. Relay
contacts can be programmed from the unit human
interface.This relay can be programmed to pick up on any
one or groupof diagnostics from theunit human interface.

76 SCXG-SVX01H-EN

Controls

Status/Annunciator Output

The status annunciator output is an internal function

within the RTM module on CV and VAV units. It provides:

a. diagnostic and mode status signals to the remote

panel (LEDs) and to the Human Interface.

b. control of the binary alarm output on the RTM.

c. control of the binary outputs on the GBAS module

to inform the customer of the operational status
and/or diagnostic conditions.

Occupied/Unoccupied Inputs

There are four ways to switch to occupied/unoccupied:

1. Field-supplied contact closure hard wired binary input
to the RTM

2. Programmable night setback zone sensor

3. Tracer Summit

4. Factory-mounted time clock

VAV Changeover Contacts

These contacts are connected to the RTM when daytime

heating on VAV units with internal or external hydronic
heat is required. Daytime (occupied) heating switches the
system to a CV unit operation. Refer to the unit wiring
diagram for the field connection terminals in the unit
control panel.The switch must be rated at 12 ma @ 24VDC
minimum.

External Auto/Stop Switch

A field-supplied switch may be used to shut down unit

operation.This switch is a binary input wired to the RTM.

When opened, the unit shuts down immediately and can

be cancelled by closing the switch. Refer to the unit wiring
diagrams (attached to the unit control panel) for proper
connection terminals.The switch must be rated for 12 ma
@ 24 VDC minimum.This input will override all VOM
inputs, if the VOM option is on the unit.

Occupied/Unoccupied Contacts

To provide night setback control if a remote panel with

night setback was not ordered, install a field-supplied
contact.This binary input provides the building’s
occupied/unoccupied status to the RTM. It can be initiated
by a time clock, or a building automation system control
output.The relay’s contacts must be rated for 12 ma @ 24

VDC minimum. Refer to the appropriate wiring diagrams

(attached to the unit control panel for the proper
connection terminals in the unit control panel.

Emergency Stop Input

A binary input is provided on the RTM board for

installation of a field-supplied normally closed (N.C.)
switchto use duringemergency situations to shut downall
unit operations. When open, an immediate shutdown
occurs. An emergency stop diagnostic enters the human
interface and the unit will require a manual reset. Refer to
the unit wiringdiagrams (attached to theunit control panel

for the proper connection terminals.The switch must be
rated for 12 ma @ 24 VDC minimum. This input will
override all VOM inputs, if the VOM option is on the unit.

VAV Box Option

To interlockVAV box operation with evaporator fan and

heat/cool modes, wire theVAV boxes/air valves toVAV box
control connections on the terminal block.

Supply Duct Static Pressure Control

The RTM relieson input from the duct pressure transducer

when a unit is equipped with VFD to set the supply fan
speed to maintain the supply duct staticpressure to within
the static pressure setpoint deadband.

RTM Sensors

RTM sensors include: zone sensors with or without
setpoint inputs and modes, supply air sensor, duct static
pressure, outside air temperature, outside air humidity,
airflow proving, and dirty filter.

Table 44. RTM sensor resistance vs. temperature

Temperature °FResistance, 

-40 346.1 71 11.60

-30 241.7 72 11.31

-20 170.1 73 11.03

-10 121.4 74 10.76

-5 103.0 75 10.50
0 87.56 76 10.25
5 74.65 77 10.00

10 63.8 78 9.76
15 54.66 79 6.53
20 46.94 80 9.30
25 40.40 85 8.25
30 34.85 90 7.33
35 30.18 100 5.82
40 26.22 105 5.21
45 22.85 110 4.66
50 19.96 120 3.76
55 17.47 130 3.05
60 15.33 140 2.50
65 13.49 150 2.05
66 13.15 160 1.69
67 12.82 170 1.40
68 12.50 180 1.17
69 12.19 190 0.985
70 11.89 200 0.830

Note: Mode boundaries are 1000 to 40,000 ohms. Other boundaries are

equal to the midpoint between the nominal mode resistance

ohms

Temperature °FResistance,

ohms



SCXG-SVX01H-EN 77

Controls

Table 45. RTM setpoint analog inputs

Cooling or Heating

Setpoint Input, °F

(using RTM as zone

temp. source) ohms

40 40 1084
45 45 992
50 50 899
55 55 796
60 60 695
65 65 597
70 70 500
75 75 403

80 80 305
NA 85 208
NA 90 111

Cooling Setpoint Input, °F

(using RTM as supply air temp.

source) resistance,



Table 46. RTM resistance value vs. system operating

mode

Resistance applied
to RTM mode input

terminals, ohms

2320 auto off off
4870 auto cool

7680 auto auto auto
10,770 on off
13,320 on cool
16,130 on auto
19,480 auto heat
27,930 on heat

CV units VAV units

fan mode

system

mode

system

mode

Compressor Module (MCM) - Standard on all Units

The compressor module, (single circuit and multiple

circuit) energizes the appropriate compressors and
condenser fans upon receiving a request for mechanical
cooling. It monitors the compressor operation through
feedback information it receives from various protection
devices.

for service mode.To use a RHI, the unit must be equipped
with an optional interprocessor communications bridge
(IPCB). Model number digit 32 (=2) indicates if the ICPB
was ordered with the unit. If not, contact your localTrane
representative to order an ICPB kit for field installation.

The RHI can be located up to 1,000 feet (304.8 m) from the

unit. A single RHI can monitor and control up to four self­contained units if each one contains an IPCB.The IPCB
switches must be set as SW1- off, SW2 - off, and SW3 - on.

Interprocessor Communications Board •
Option used with RHI

The interprocessor communication board expands

communications from the rooftop unit's UCM network to
a remote humaninterface panel. DIPswitchsettings on the
IPCB module forthis application are; switches 1 and 2“off,”
switch 3 “on.”

Waterside Module - Standard on all water-

cooled units

Waterside module (WSM) controls all water valves based

on unit configuration. In addition, the WSM monitors
waterflow proving and the following temperatures:

• entering water

• entering air low

• mixed air

• entering condenser water

• refrigerant circuit 3:

• saturated condenser

• evaporator frost

• refrigerant circuit 4:

• condenser

• evaporator

Cooling Tower Interlock

To interlock condenser pump/tower with cooling

operation, wire the cooling tower to an external 115 volt
control power source, to ground, and to control terminal
block. Normally open/closed contacts are provided.

Human Interface Module - Standard on all Units

The human interface (HI) module enables the operator to

adjust the operating parameters for the unit using it's 16­key keypad on the human interface panel. The HI panel
provides a two line, 40 character, clear language (English,
Spanish, or French) LCD screen with unit status
information and menus to set or modify operating
parameters. It is mounted in the unit’s main control panel
and accessible through the unit’s control panel door.

Remote Human Interface Module Option

The optional remote-mount human interface (RHI) panel

has all the functions of the unit-mounted version except

78 SCXG-SVX01H-EN

Heat Module

The heat module is standard on all units with factory-

installed heat. It controls the unit heater to stage up and
down to bring the temperature in the controlled space to
within the applicable heating setpoint. Also, it includes a
freezestat, morning warmup, and heating outputs.

Ventilation Override Module (VOM) Option

The ventilation override module can be field-configured

with up to five different override sequences for ventilation
override control purpose. When any one of the module’s
five binary inputs are activated, it will initiate specified
functions such as; space pressurization, exhaust, purge,
purge with duct pressure control, and unit off.

Controls

Once the ventilation sequences are configured, they can
be changed unless they are locked using the HI. Once
locked, the ventilation sequences cannot be unlocked.

The compressors and condenser fans disable during the

ventilation operation. If more than one ventilation
sequence activates, the onewith the highest priority (VOM

“A”) begins first, withVOM “E” having lowest priority and

beginning last.

A description of the VOM binary inputs follows below.

UNIT OFF sequence “A”

When complete system shut down is required, the

following sequence can be used.

• Supply fan – off

• Supply fan VFD – off (0 Hz)

• Outside air dampers – closed

• Heat – all stages – off, modulating heat output at 0 vdc

• Occupied/Unoccupied output – de-energized

• VO relay – energized

• Exhaust fan (field-installed) - off

• Exhaust damper (field-installed) - closed

PRESSURIZE sequence “B”

This override sequence can be used if a positively

pressured space is desired instead of a negatively
pressurized space.

• Supply fan – on

• Supply fan VFD – on (60 Hz)/VAV boxes – open

• Outside air dampers – open

• Heat – all stages – off, hydronic heat output at 0 vdc

• Occupied/ unoccupied output - energized

• VO relay - energized

• Exhaust fan (field-installed) - off

• Exhaust damper (field-installed) - closed

EXHAUST sequence “C”

With the building’s exhaust fans running and the unit’s

supply fan off, the conditioned space becomes negatively
pressurized.This is desirable for clearing the area of
smoke when necessary; i.e. from an extinguished fire, to
keep smoke out of areas that were not damaged.

• Supply fan – off

• Supply fan VFD – off (0 Hz)

• Outside air dampers – closed

• Heat – all stages – off, hydronic heat output at 0 vdc

• Occupied/Unoccupied output – de-energized

• VO relay – energized

• Exhaust fan (field-installed) - on

• Exhaust damper (field-installed) - open

PURGE sequence “D”

This sequence can purge the air out of a building before

coming out of unoccupied mode of operation in a VAV
system. Also, it can be used to purge smoke or stale air.

• Supply fan – on

• Supply fan VFD – on (60 hz)/VAV boxes – open

• Outside air damper – open

• Heat – all stages – off, modulating heat output at 0 vdc

• Occupied/Unoccupied output – energized

• VO relay – energized

• Exhaust fan (field-installed) - on

• Exhaust damper (field-installed) - open

PURGE with duct pressure control “E”

This sequence can be used when supply air control is

required for smoke control.

• Supply fan – on

• Supply fan VFD – on (if equipped)

• Outside air dampers – open

• Heat – all stages – off, hydronic heat output at 0 vdc

• Occupied/unoccupied output – energized

• VO relay – energized

• Exhaust fan (field-installed) - on

• Exhaust damper (field-installed) - open

Note: Each system (cooling, exhaust, supply air, etc.)

within the unit can be redefined in the field for each
of the five sequences, if required. Also the
definitions of any or all of the five sequences may
be locked into the software by simple key strokes at
the human interface panel. Once locked into the
software, the sequences cannot be changed.

Trane IntelliPak Communications Modules

BACnet Communications Interface (BCI-I)
Module

The BACnet Communication Interface for IntelliPak self-

contained (BCI-I) controller expands communications
from the unit UCM network toTracer SC or a 3rd party
building automation system, utilizing BACnet, and allows
external setpoint and configuration adjustment and
monitoring of status and diagnostics.The BCI-I utilizes the
BACnet defined MS/TP protocol as defined in ASHRAE
standard135-2004. This controller works in standalone
mode, withTracer SC or when connected to a 3rdparty
building automation system that supports BACnet.

LonTalk® Communications Interface (LCI-I)
Module

The LonTalk Communication Interface for IntelliPak self-

contained (LCI-I) controller expands communications
from the unit UCM network to aTraneTracer Summit or a

SCXG-SVX01H-EN 79

Controls

3rd party building automation system, utilizing LonTalk,
and allows external setpoint and configuration
adjustment and monitoring of status and diagnostics.The
LCI-I utilizes an FTT-10A FreeTopology transceiver, which
supports nonpolarity sensitive, free topology wiring,
which allows the system installer to utilize star, bus, and
loop architectures.This controller works in standalone
mode, peer-to-peer with one or more other units, or when
connected to aTraneTracer Summit or a 3rd party building
automation system that supports LonTalk.

Exhaust/Comparative Enthalpy (ECEM) Module

(Option used on units with comparative enthalpy
option)

The exhaust/comparative enthalpy module receives

information from the return air humidity sensor, and the
RTM outside air temperature sensor and outside air
humidity sensor, the outside air humidity sensor and
temperature sensor to utilize the lowest possible enthalpy
level when consideringeconomizer operation. Inaddition,
it receives space pressure information to maintain the
space pressure within the setpoint control band. Refer to
the Figure 61, p. 80 for humidity vs. voltage values.

Figure 61. Relative humidity vs. voltage

Ventilation Control Module (VCM)

(Available only with Traq™ Damper Option)

The ventilation control module (VCM) is located in the

airside economizer section of the unit and linked to the
unit’s UCM network. Using a velocity pressure transducer/
solenoid (pressure sensing ring) in the fresh air section
allows the VCM to monitor and control fresh air entering
the unit to a minimum airflow setpoint. See Figure 62,

p. 80 for a detail view of the velocity pressure transducer/

solenoid assembly.

An optional temperature sensor can be connected to the
VCM to enable control of a field installed fresh air

preheater.

Also, a field-provided CO
VCM to control CO

2

minimum cfm upward as the CO

The maximum effective (reset) setpoint value for fresh air

entering the unit is limited to the system’s operating cfm.

Table 47, p. 80 lists the minimum outside air cfm vs. input

voltage.

Table 47. Minimum outside air setpoint w/VCM module

and Traq™ sensing

Unit Input Volts CFM

SXWG 20 0.5 - 4.5 vdc 6,350-8,500
SXWG 25 0.5 - 4.5 vdc 7,250-10,625
SXWG 30 0.5 - 4.5 vdc 7,250-12,750
SXWG 35 0.5 - 4.5 vdc 7,250-14,875

SXRG 20 0.5 - 4.5 vdc 7,250-8,500
SXRG 25 0.5 - 4.5 vdc 7,250-10,625
SXRG 32 0.5 - 4.5 vdc 7,250-13,600

sensor can be connected to the

2

reset.The reset function adjusts the

concentrations increase.

2

Generic Building Automation System Module Option

The generic building automation system module (GBAS)

provides broad control capabilities for building
automation systems other thanTrane’sTracer system. A
field provided potentiometer or a 0-5 vdc signal can be
applied to any of the inputs of the GBAS to provide the

Figure 62. Velocity pressure transducer/solenoid

assembly

Tube from low side
of Transducer

Pressure
Transducer

Ventilation
Control Module

Tube from

low side

of Velocity

Ring

Solenoid

Tube from high side
of Transducer

80 SCXG-SVX01H-EN

following points:

GBAS Analog Inputs

Four analog inputs that can be configured to be any of the
following:

5. occupied zone cooling

6. unoccupied zone cooling

7. occupied zone heating

8. unoccupied zone heating

9. SA cooling setpoint

10. SA heating setpoint

11. space static pressure setpoint

12. SA static pressure setpoint

Controls

GBAS Binary Outputs

Five binary outputs toprovide diagnostics, signaling up to
five alarms. Each of the five (5) relay outputs can be
mapped to any/all of the available diagnostics. Eachoutput
contains a dry N.O. and N.C. contact with a VA rating of 2
amps at 24 VAC.

GBAS Binary Input

One binary input for the self-contained unit to utilize the
demand limit function.This function is operational on
units with a GBAS and is used to reduce electrical
consumption at peak load times. Demand limiting can be
set at either 50% or 100%. When demand limiting is
needed, mechanical cooling and heating (with field­provided 2-stage electric heat only) operation are either
partially (50%), or completely disabled (100%) to save
energy.Thedemand limit definition is user definable at the
HI panel. Demand limit binary input accepts a field
supplied switch or contact closure. When the need for
demand limiting has been discontinued, the unit’s cooling/
heating functions will again become fully enabled.

GBAS Communication (Analog Inputs)

The GBAS accepts external setpoints inthe form of analog

inputs for cooling, heating, supply air pressure. Refer to
the unit wiring diagram for GBAS input wiring and the
various desired setpoints with the corresponding DC
voltage inputs.

Any of the setpoint or output control parameters can be

assigned to each of the four analog inputs on the GBAS
module. Also, any combination of the setpoint and/or
output control parameters can be assigned to the analog
inputs through the HI.To assign the setpoints apply an
external 0-5 vdc signal:

1. directly to the signal input terminals, or

2. to the 5 vdc source at the GBAS module with a 3-wire
potentiometer.

Note: There is a regulated 5 vdc output on the GBAS

module that can be used with a potentiometer as a
voltage divider.The recommended potentiometer
value is 1000-100,000 ohms.

The setpoints are linear between the values shown in

Table 48, p. 82. Reference Table 49, p. 82 for

corresponding input voltage setpoints. Following are
formulas to calculate input voltage or setpoint. SP =
setpoint, IPV = input voltage.

If the setpoint range is 50-90°F:

IPV = (SP - 50) (0.1) + 0.5

SP = [(IPV - 0.5)/0.1] + 50

If the setpoint range is 40-90°F:

IPV = (SP - 40)(0.8) + 0.5

SP = [(IPV - 0.5)/0.08] + 40

IPV = (SP - 40)(0.029) + 0.5

SP = [(IPV - 0.5)/0.029] + 40

If the static pressure range is 0.03-0.3 iwc:

IPV = (SP - 0.03)(14.8) + 0.5

SP = [(IPV - 0.5)/14.8] + 0.03

If the static pressure range is 0.0-5.0 iwc:

IPV = (SP)(0.8) + 0.5

SP = [IPV/(0.8 + 0.5)]

GBAS Demand Limit Relay (Binary Input)

The GBAS allows the unit to utilize the demand limit

function by usinga normally open(N.O.) switch to limitthe
electrical power usage during peak periods. Demand limit
can initiate by a toggle switch closure, a time clock, or an
ICS control output.These contactsmust be rated for 12 ma
@ 24 VDC minimum.

When the GBAS module receives a binary input signal

indicating demand limiting is required, a command
initiates to either partially (50%) or fully (100%) inhibit
compressor and heater operation.This can be set at the HI
using the setup menu, under the“demand limit definition
cooling” and “demand limit definition heating” screens. A
toggle switch, time clock, or building automation system
control output can initiate demand limiting.

If the cooling demand limit is set to 50%, half of the cooling
capacity will disable when the demand limit binary input
closes.The heating demand limit definitioncan only be set
at 100%, unless the unit has field-provided two-stage
electric heat. In thatcase, ifthe heating demand limit isset
to 50%, half or one stage of heating disables when the
demand limit binary input closes. If the demand limit
definition is set to 100%, then all cooling and/or heating
will disable when the demand limit input closes.

GBAS Diagnostics (Binary Outputs)

The GBAS can signal up to five alarm diagnostics, which

are fully mappable through the setup menu on the HI.

These diagnostics, along with the alarm output on the

RTM, allow up to six fully mappable alarm outputs.

Each binary output has a NO and NC contact with a rating
of two amps at 24VAC.The five binary outputs are factory
preset as shown on the unit wiring diagram (on the unit
control panel door). However, these outputs can be field
defined in a variety of configurations, assigning single or
multiple diagnostics to any output.

For a complete listing of possible diagnostics, see the

IntelliPak Self-Contained Programming Guide, PKG­SVP01*-EN. For terminal strip locations, refer to the unit

wiring diagram for the GBAS.

If the setpoint range is 40-180°F:

SCXG-SVX01H-EN 81

Controls

Table 48. GBAS analog input setpoints

control parameter signal range setpoint range

occupied zone cooling setpoint 0.5 to 4.5 vdc 50 to 90°F
(CV units only)
unoccupied zone cooling

setpoint
(CV and VAV)
occupied zone heating setpoint 0.5 to 4.5 vdc 50 to 90°F
(CV units only)
unoccupied zone heating

setpoint
(CV and VAV)
supply air cooling setpoint 0.5 to 4.5 vdc 40 to 90°F
(VAV units only)
supply air hydronic heating

setpoint
(VAV units only)
space static pressure setpoint 0.5 to 4.5 vdc 0.03 to 0.30 IWC
supply air pressure setpoint 0.5 to 4.5 vdc 0.0 to 5.0 IWC
(VAV units only)

Notes:

1. Input voltages less than 0.5 vdc are considered as 0.5 vdc input
signal is lost, the setpoint will "clamp" to the low end of the setpoint
scale. No diagnostic will result from this condition.

2. Input voltages greater than 4.5 vdc are considered to be 4.5 vdc.

3. The actual measured voltage is displayed at the HI.

0.5 to 4.5 vdc 50 to 90°F

0.5 to 4.5 vdc 50 to 90°F

0.5 to 4.5 vdc 40 to 180 °F

Table 49. GBAS input voltage corresponding setpoints

Temp.

Volts

0.5 50 1.6 60 2.6 70 2.7 80

0.6 51 1.7 61 2.7 71 2.8 81

0.7 52 1.8 62 2.8 72 2.9 82

0.8 53 1.9 63 2.9 73 3.0 83

0.9 54 2.0 64 3.0 74 3.1 84

1.0 55 2.1 65 3.1 75 3.2 85

1.1 56 2.2 66 3.2 76 3.3 86

1.2 57 2.3 67 3.3 77 3.4 87

1.3 58 2.4 68 3.4 78 3.5 88

1.5 59 2.5 69 3.5 79 3.6 89

1.6 60

1.7 61

1.8 62

1.9 63

2.0 64

2.1 65

2.2 66

2.3 67

2.4 68

°F Volts

Temp.

°F Volts

Temp.

°F Volts

Temp.

°F

Input Devices and System Functions

Following are basic input device and system function
descriptions used within the UCM network on IntelliPak
self-contained units. Refer to the unit wiring diagrams for
specific connections.

Water Purge

NOTICE:

Proper WaterTreatment!

The use of untreated or improperly treated water in a

CenTraVac could result in scaling, erosion, corrosion,
algae or slime. It is recommended that the services of a
qualified water treatment specialist be engaged to
determine what water treatment, if any, is required.

Trane assumes no responsibility for equipment failures

which result from untreated or improperly treated
water, or saline or brackish water.

During the unoccupied mode, water-cooled units will
periodically circulate water through the condensers and
waterside economizer if the user has enabled the purge
function at the HI. The water purge function circulates
water to introduce fresh water-treatment chemicals and
help prevent water stagnation.The number of hours
between each periodic purge, or purge duration, is user­defined at the HI between 1-999 hours. Ifthe periodic purge
timer expires whilethe unit isin occupied mode, it will wait
for the next available unoccupied time before initiating
water purge. Contrary, if a request for cooling occurs
during a purgesequence, purge willterminate and cooling
will commence.

Compressor Circuit Breakers

The compressors are protected by circuit breakers that

interrupt the compressor power supply if the current
exceeds the breakers “must trip” value. During a request
for compressor operation, if the compressor module
(MCM or SCM) detects a problem outside of it’s normal
parameters, it turns any operating compressor(s) on that
circuit off, locks out all compressor operation for that
circuit, and initiates a manual reset diagnostic.

Low Pressure Control

Low pressure (LP) control is accomplished using a binary
input device mounted on the suction line, near the
compressor. If suction pressure drops to 49 (water­cooled), 36 (air-cooled) ± 6 psig, or below, the switch
opens.

If the switch is open at start, no compressors on thatcircuit
will operate.They are locked out and a manual reset
diagnostic initiates. If the LP switch opens after a
compressor start, all compressors on that circuit will stop
and remain off a minimum 3 minutes before restarting. If
the LP cutout trips four times in the first three minutes of
operation, all compressors on that circuit lockout and a
manual reset diagnostic initiates.

82 SCXG-SVX01H-EN

Controls

LP switches close at 74 (water-cooled) and 61 (air-cooled)
± 6 psig.

Evaporator Temperature Sensor Frostat™

The evaporator temperature sensor is an analog input

device used to monitor refrigerant temperature inside the
evaporator coil to prevent coil freezing. It isattachedto the
suction line near the evaporator coil with circuits 1 and 2
connected to theSCM/MCM and circuits 3 and4 connected
to theWSM.The coil frost cutout temperature is factory set
at 30°F. It is adjustable at the HI from 25-35°F.The
compressors stage off as necessary to prevent icing. After
the last compressor stages off, the compressors will
restart when the evaporator temperature rises 10°F above
the coil frost cutout temperature and the minimum three
minute “off” time elapses.

Saturated CondenserTemperature Sensors

The saturated condenser temperature sensors are analog

input devices.They aremounted inside a temperature well
located on a condenser tube bend on air-cooled units, and
in the condenser shell on water-cooled units.The sensors
monitor the saturated refrigerant temperature inside the
condenser coil and are connected to the SCM/MCM for
circuits 1 and 2 (air or water cooled), and WSM for circuits
3 and 4 (only water-cooled).

Head Pressure Control

Head pressure control is accomplished using two
saturated refrigerant temperature sensors on air-cooled
units and up to four sensors on water-cooled units.

Air-cooled units: During a request for compressor

operation when the condensing temperature rises above
the lower limit of the control band, the compressor
module (SCM/MCM) sequences condenser fans on. If the
operating fans cannot bring the condensing temperature
to within the control band, more fans turn on. As the
saturated condensing temperature approaches the lower
limit of the control band, fans sequence off.The minimum
on/off time for condenser fan staging is 5.2 seconds. If the
system is operating at a given fan stagebelow 100% for 30
minutes the saturated condensing temperature is above
the efficiency check point setting, a fan stagewill be added.
If the saturated condensing temperature falls below the
efficiency check point setting, fan control remains at the
present operating stage. If the fan stage cycles four times
within a 10 minute period, the lower limit temperature is
redefined as being equal to the lower limit minus the
temporary low limit suppression setting.The unit will
utilize this new low limit temperature for one hour to
reduce condenser fan short cycling.

Water-cooled: Units without WSE, the condenser valve

modulates to maintain an average saturated condenser
temperature. Units with WSE, if economizing and
mechanical cooling is necessary the economize valve will
sacrifice free cooling and modulate to maintain
condensing saturated temperature. If not economizing,
the condenser valve will modulateto maintain condensing

saturated temperature. Water-cooled units without head
pressure control will lock out mechanical cooling at
entering condenser water temperatures below 54°F.
Mechanical cooling will resume when the entering
condenser water temperature exceeds 58°F.

Low Ambient Control (Air-Cooled Units Only)

The low ambient modulating output on the compressor

module is functional on all units with or without the low
ambient option. When the compressor module stages up
to it's highest stage (stage 2 or 3 depending on unit size),
the modulating output is 100% (10VDC). When the control
is at stage 1, the modulatingoutput (0-10VDC) controls the
saturated condensing temperature to within the
programmable condensing temperature low ambient
control point.

Low Ambient Compressor Lockout (Air-Cooled
Units Only)

The low ambient compressor lockout utilizes an analog

input device. When the system is configured for low
ambient compressor lockout, the compressors will not
operate if the temperature of the outside air falls below the
lockout setpoint. When the temperature rises 5°F above
the lockout setpoint, the compressors will operate.The
setpoint for units without the low ambient option is 50°F.
For units with the low ambient option, the setpoint is 0°F.

The setpoints are adjustable at the human interface panel.

Return Air Temperature Sensor

The return air temperature sensor is an analog input

device used with a return humidity sensor on units with
the comparative enthalpy option.The sensormonitors the
return air temperature and compares it to the outdoor
temperature to establish which temperature is best suited
to maintain cooling requirements. It is mounted in the
return air path and connected to the ECEM.

Supply Fan Circuit Breaker, Fuses, and
Overloads

The supply fan motor is protected by either circuit

breakers fuses or a combination of fuses and overloads,
dependent upon unit configuration. Circuit breakers are
used on units without a VFD.They will trip and interrupt
the motor power supply if the current exceeds the breaker
trip value.The RTM shuts all system functions off when
detecting an open fan proving switch. Units with aVFD
have fuses to protect theVFD and motor. Units with a VFD
w/bypass have fuses to protect VFD circuit and overloads
to protect the motor when in bypass.

Supply Air Temperature Low Limit

The supply air temperature low limit function uses the

supply air temperature sensor input to modulate the
economizer damper to the minimumposition if the supply
air temperature falls below the occupied heating setpoint
temperature.

SCXG-SVX01H-EN 83

Controls

Supply Air Temperature Sensor

The supply air temperature sensor is an analog input

device. It monitors the supply air temperature for supply
air temperature control, supply air temperature reset,
supply air temperature low limiting, and supply air
tempering. It is mounted in the supply air discharge
section of the unit and connected to the RTM.

Supply Airflow Proving Switches

This is binary input device used on units to signal the RTM

when the supply fan is operating. It is mounted in the
supply fan section and is connected to the RTM. During a
request for fan operation and if the differential switch
opens for 40 consecutive seconds, compressor operation
turns off, heat operation turns off, the request for supply
fan operation is turns off and locks out, economizer
damper option closes, and a manual reset diagnostic
initiates.

Low Entering Air Protection Device (LEATPD)

The low enteringair protection device(LEATPD) is a binary

input on units with hydronic heat or a waterside
economizer. It is optional on water-cooled units.

If the LEATPD is on a unit with factory-installed heat, it is
mounted in the heat section and connected to the heat
module. If the entering air temperature to the heating coil
falls to 40°F, the normally open contacts on the LEATPD
close and cause the following events:

a. the hydronic heat actuator fully opens.

b. the supply fan turns off

c. the outside air damper closes

d. the SERVICE light at the remote zone sensor option

turns on.

e. a LEATPD diagnostic displays at the human

interface panel.

If the LEATPD is on a water-cooled unit without factory­installed heat, it is wired to the WSM. It will trip if the
entering water temperature falls to 34°F, open the
economizer valve, and energize the pump output.

the filter section and connected to the RTM. A diagnostic
SERVICE signal displays at the remote panel if the
pressure differential across the filters is at least 0.5” w.c.

The contacts automatically open when the pressure

differential across the filters decrease to 0.4” w.c.The
switch differential is field adjustablebetween 0.17” to 5.0”
w.c. ± 0.05 “.

High Duct Static Switch Option

The high duct static switch is field-mounted in the

ductwork or plenums with smoke dampers. It will cause a
manual reset diagnostic if the duct static exceeds the pre­set static limit.The static limit is adjustable at the HI.

High Duct TempThermostat Option On Units
with an LCI-I

The high duct temperature thermostats are binary input

devices used on units with aTrane communication
interface module (Tracer/LCI-I).They provide a high limit
unit shutdown and require a manual reset.The
thermostats are factory set to open if the supply air
temperature reaches 240°F, or the return air temperature
reaches 135°F. Once tripped, the thermostat requires a
manual reset. Reset by pressing the sensor’s reset button
when the air temperature decreases approximately 25°F
below the cutout point.

Filter Switch

The filter switch is a binary input device that measures the

pressure differential across the unit filters. It is mounted in

84 SCXG-SVX01H-EN

Pre-Startup

Pre-Startup Checklist

Complete this checklist after installing unit to verify all
recommended installation procedures are complete
before start-up.This does not replace the detailed
instructions in the appropriate sections of this manual.

Always read the entire sectioncarefully to become familiar

with the procedures.

Supply Fan

• Verify the fan and motor shafts are parallel.

• Verify the fan and motor sheaves are aligned.

• Check the fan belt condition and tension. Adjust the
tension if belts are floppy or squeal continually.
Replace worn or fraying belts in matched sets..

• Ensure the fan rotates freely.

• Tighten locking screws, bearing set screws and
sheaves.

• Ensure bearing locking collars do not wobble when
rotated.

• Remove fan assembly tie down bolts. On 20 - 35 ton
units, do not remove the fan assembly tie down bolts
if the fan speed is 750 rpm or less.

• Ensure fan rotation is in direction of arrow on fan
housing. If incorrect, verify incoming power phasingis
correct. Switch wires on the fan contact to properly
phase fan if necessary.

Electrical

• Verify electrical connections are tight.

Components

• Verify liquid line service valve, and suction and
dischargeservice valves if present, are open at startup.

Note: Each compressor suction line contains a low

pressure sensor that will shut the compressor
down in low pressure situations. See Table 41,

p. 68.

• Ensure system components are properly set and
installed.

Note: Thermal expansion valve superheat is factory set

and requires no field adjustment. Operating
superheat should be between 14-20°F. Actual
superheat depends on several factors (operating
conditions, system load step, system charge,
piping and condenser head pressure control.)

Ductwork

• Ensure trunk ductwork to VAV boxes is complete and
secure to prevent leaks.

• Verify that all ductwork conforms to NFPA 90A or 90B
and all applicable local codes

Water-Cooled Unit Piping

• Verify condensate drain, water piping drain plugs,
economizer header, and condenser vent plug are
installed.

Air-Cooled Units Only

• Verify leak test was performed after refrigerant piping
was installed.

• Verify liquid line filter driers installed.

Units with Hydronic Heat

• Verify the entering water temperature sensor is
installed upstream of the hydronic coil.

Units with Electric Heat

• Verify the supply air temperature sensor is
downstream of the electric heat coil.

SCXG-SVX01H-EN 85

Start-up

WARNING

Live Electrical Components!

During installation, testing, servicing and
troubleshooting of this product, it may be necessary to
work with live electrical components. Have a qualified
licensed electrician or other individual who has been
properly trained in handling live electrical components
perform these tasks. Failure to follow all electrical safety
precautions when exposed to live electrical
components could result in death or serious injury.

NOTICE:

Compressor Damage!

Never manually or automatically pump down system
below 7 psig.This will cause the compressor to operate
in a vacuum and result in compressor damage.

NOTICE:

Compressor Damage!

Keep crankcase heaters on whenever refrigerant is in
the system. If crankcase heaters have not been on with
refrigerant in the system, turn the crankcase heaters on
for a minimum of 24hours before starting compressors.
Failure to follow the above could result in compressor
failure or reduced compressor life.

To start the unit, complete the following steps in order.

Review “Preliminary Refrigerant Charging,” p. 37 in
Installation section if applicable. Confirm all steps were
completed.

Air Cooled Only

• Charging is more accurate at higher outdoor

temperatures, if the outdoor temperature is less
than 80°F, temporarily disable fan pressure control
switches. See unit wiring diagrams and disconnect
wires between the switches and terminal strip.

• Do not attempt to charge system with low ambient

dampers operating (if applicable). Disable low
ambient dampers in “Open” position before
proceeding.

Evaporator load should be at least 70°F return air and 350
CFM/ton.

Work on only one circuit at a time.

Important: R-410A compressors have belly band

crankcase heaters that must be energized
24 hours before starting compressor. Power
to the unit will energize the heaters. Heaters
will be energized during off-cycle as long as
the unit has power. Failure to perform these
pre-start instructions could result in
compressor damage.

3. Verifycompressor crank case heaters have been on for
at least 24 hours.

4. Make sure all service valves are open.

5. Attach a thermocoupletype temperature sensoron the
liquid line close to the liquid line service valve.To
ensure an accurate liquid temperature reading, clean
the line where the sensor is attached. After securing
sensor to line, insulate the sensor and line to isolate it
from ambient air.

6. Attach a set of service gauges onto the suction and
discharge gauge ports.

7. Check low side pressure. Low pressure cutout opens
below, and closes above, values in
low side pressure is less than open psig, refrigerant
may need to be added to suction line before starting
compressor(s) to close the switch. SLOWLY meter into
the suction line only as much R-410A as needed to
close the lowpressure cutout. UsetheVAPOR charging
connection. If possible, plan to use this entire
refrigerant bottle on thesame unit in order to minimize
fractionalization. Use an accurate scaleto measure and
record the amount of R-410A added.

Table 41, p. 68.If

WARNING

Hazardous Voltage!

Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Failure to disconnect power
before servicing could result in death or serious injury.

8. Switch field supplied unit disconnect “OFF”. Open the
unit control box and plug in reset relay only for circuit
being started.

9. Turn 115 volt control circuit switch “ON”. Close control
box and switch field supplied unit disconnect “ON”.
Unit power should be off no longer than 60 minutes to
prevent refrigerant migration to compressor sumps. If
power is off for longer than 60 minutes, allow time for
crankcase heaters to drive refrigerant from
compressor sumps before starting compressors.

10. Adjust setpoints at the HI.

Note: Sufficient cooling load must be visible to

refrigerant circuit controls for mechanical
refrigeration to operate. If necessary, temporarily
reduce discharge air setpoint to verify refrigeration
cycle operation.

11. Check voltage at all compressor terminals to ensure it
is within 10% of nameplate voltage.

12. Check voltage imbalance from these three voltage
readings at each compressor. Maximum allowable
voltage imbalance, phase to phase is 2%.

13. Start the first step compressor only.

86 SCXG-SVX01H-EN

Start-up

14. Check amp draw at compressor terminals. RLA and
LRA are on the unit nameplate.

15. Measure amp draw at evaporator fanmotor terminals.
FLA data is on the motor nameplate.

NOTICE:

Compressor Damage!

Improper power phasing could cause the compressor
to run backward. Compressor could be running
backward if it is noisy, low side shell gets hot, suction
pressure does not drop within 5 seconds after startup
and compressor only draws half of the expected amps.
Stop the compressor immediately and have a qualified
electrician or technician properly trained in 3-phase
power correct the wiring. Failure to do the above could
result in compressor damage.

16. As soon as a compressor starts, verify correct rotation.
If a scroll compressor is allowed to run backwards for
even a very short period of time, internal compressor
damage could occur and compressor life could be
reduced.When rotating backwards scroll compressors
make a loud noise, do not pump, and draw about 1/2
expected amps, and the low side shell gets hot.
Immediately shut offa compressor rotating backwards
and correct wiring.

WARNING

Rotating Components!

During installation, testing, servicing and
troubleshooting of this product it may be necessary to
work with live and exposed rotating components. Have
a qualified or licensed service individual who has been
properly trained in handling exposed rotating
components, perform these tasks. Failure to follow all
safety precautions could result in rotating components
cutting and slashing technician which could result in
death or serious injury.

17. Air Cooled Only: Check condenser fans for proper
rotation. As viewed from the top ofthe unit, the correct
rotation direction is clockwise. If running backwards,
correct wiring

18. After 10 minutes, start second compressor of manifold
circuits.

19. Allow10 minutes forcircuit operation to stabilize at full
load.

20. Complete charging, if required.

.

Final Refrigerant Charge

If full charge was not usedduring installation, follow these
steps:

1. Determine remaining charge required by subtracting
charge added during “Preliminary Refrigerant

Charging,” p. 37 from the total.

NOTICE:

Compressor Damage!

Avoid compressor liquid slugging. Only add liquid in

the suction line when the compressor is running. Use
extreme caution to meter liquid refrigerant in to the
suction line slowly. If liquid is added too rapidly,
compressor oil dilution and oil pump out could occur.
Failure to follow the above could result in compressor
failure or reduced compressor life.

NOTICE:

Compressor Damage!

Do not overcharge system. Excessive refrigerant
charging can cause compressor liquid slugging at
startup and compressor (and/or condenser fans short
cycle). Overcharging could result in compressor failure
or reduced compressor life.

2. With all circuit compressors running, SLOWLY meter
remaining R-410A into suction line from LIQUID
charging connection.

3. Use an accurate scaleto measure,then record amount
of R-410A added.

4. After unit has been operating for approximately 30
minutes at full load measure then record operating
pressures.

• Air Cooled Only: Operating pressure

measurement must be made with all condenser
fans running.

5. Repeat for other circuits.

Start-up Procedure

Using startup log on following pages, establish nominal
conditions for consistent measurements as follows:

• Leaving air greater than 60°F

• Entering air temperature = 70 to 90°F

• Entering water temperature > 60°F

With all compressors running at full load:

1. Compute superheat fromthe suction line pressure and
temperature at the compressor on each circuit. Adjust
the thermal expansion valve settings if necessary.
Superheat should be between 14 and 20°F.

2. Inspect refrigerant flow in the liquid line sight glass.
Flow should be smooth and even, with no bubbles
once the system has stabilized.

Note: Sight glass moisture indicator may show caution

or wet at start-up. May need up to 12 hours of
operation for system to reach equilibrium and
correctly show moisture.

Normal startup will occur provided thatTracer Summit is
not controlling the module outputs or the generic BAS is

SCXG-SVX01H-EN 87

Start-up

not keeping the unit off.To preventTracer Summit from
affecting unit operation, removeTracer wiring and make
required changes to setpoint and sensor sources.

Operating & Programming Instructions

Reference the IntelliPak™ Self-Contained Programming
Guide, PKG-SVP01B-EN, for available unit operating

setpoints and instructions.A copyships with each unit. For
units with theVFD option, referencethe installer guide that
ships with each VFD.

Startup Log

Complete this log at unit startup.

Unit: __________________________ Unit Location: _____________________________________
Unit Voltage: _____________________ _____________________ _____________________

ABC

Evaporator:

evaporator fan motor horsepower: _____________

evaporator fan rpm (actual): _____________________________

evaporator system static (from test and balance report or actual readings):

supply duct static: __________
return duct static: __________

evaporator air conditions with both compressors operating:

entering: leaving:
dry-bulb °F: __________ dry-bulb °F: __________
wet-bulb °F: __________ wet-bulb °F: __________

evaporator system cfm (test and balance sheet or actual tested): _______________

evaporator fan
motor amps:

__________ __________ __________

ABC

Compressor Amp Draw:

circuit A: __________ __________ __________ circuit B: __________ __________ __________

AB C A B C

circuit C: __________ __________ __________ circuit D: __________ __________ __________

AB C A B C

circuit E: __________ __________ __________ circuit F: __________ __________ __________

AB C A B C

suction pressure, psig: circuit A: __________ circuit B: __________ circuit C: __________ circuit D: __________

circuit E: __________ circuit F: __________

discharge pressure, psig: circuit A: __________ circuit B: __________ circuit C: __________ circuit D: __________

circuit E: __________ circuit F: __________

super heat °F: circuit A: __________ circuit B: __________ circuit C: __________ circuit D: __________

circuit E: __________ circuit F: __________

liquid line pressure, psig: circuit A: __________ circuit B: __________ circuit C: __________ circuit D: __________

circuit E: __________ circuit F: __________

sub cooling °F: circuit A: __________ circuit B: __________ circuit C: __________ circuit D: __________

circuit E: __________ circuit F: __________

88 SCXG-SVX01H-EN

Water Cooled Units:

Circuit A:
entering water temperature °F: __________ leaving water temperature °F: __________
entering water pressure, psig: __________ leaving water pressure, psig: __________

Circuit B:
enter water temperature °F: __________ leaving water temperature °F: __________
entering water pressure, psig: __________ leaving water pressure, psig: __________

Circuit C:
entering water temperature °F: __________ leaving water temperature °F: __________
entering water pressure, psig: __________ leaving water pressure, psig: __________

Circuit D:
enter water temperature °F: __________ leaving water temperature °F: __________
entering water pressure - psig: __________ leaving water pressure, psig: __________

Circuit E:
enter water temperature °F: __________ leaving water temperature °F: __________
entering water pressure - psig: __________ leaving water pressure, psig: __________

Start-up

Circuit F:
enter water temperature °F: __________ leaving water temperature °F: __________
entering water pressure - psig: __________ leaving water pressure, psig: __________

Air Cooled Units:

(data taken from outside condensing unit)

voltage: __________ __________ __________ amp draw: __________ __________ __________

ABC A B C
entering air temperature °F:_______________________ leaving air temperature °F: __________
refrigerant pressures at condenser, psig:

____/____ sub cooling at condenser °F: __________

SCXG-SVX01H-EN 89

Maintenance

Service Access

See “Service Clearances,” p. 24 for recommended service
and code clearances.Access to thermostat unit controls is
through a hinged access panel door on the front, lower left
of the unit’s compressor section.

IntelliPak unit controls access is through a panel on the
middle right of the fan section.The panel is secured with
an automatic latch and quick-acting fasteners, which
require a screwdriver to open.

Removable front unit panels provide access to
compressors, fan, motor and belts.

Removable left side panels give access to drive side, fan
bearing, condensers, and waterside economizer control
valve.The compressor, condenser and fan motor access
panels are secured with quick-acting fasteners. Access
panels for evaporator coils, expansion and water valves,
and left fan bearing are sheet metal screws. Access to
other components for service requires removal of panels
secured with sheet metal screws. During operation, sight
glasses are viewable through portholes on the upper right
side panel of the fan section.

Variable Frequency Drives are shipped separately and field

installed. See section “Variable Frequency Drive Option

(VFD),” p. 41 for VFD related dimensions and weights.

Variable Frequency Drive (VFD)

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors.Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect
power and discharge capacitors before servicing could
result in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

The VFD access panel is hinged to allow service access to

the fan motor and belt drive components that are located
behind it.To swing the panel open:

• Remove the unit center cover panel to the left of the
VFD panel.

• Remove and discard the sheet metal shipping screws

along the top and bottom edges of the VFD panel.

• Disconnect the communications cable from the

keypad on the VFD door panel.

• Turn the two slotted-head fasteners on the right edge
of the VFD panel fully counterclockwise.

• Pull on the handle to swing the panel 180°.

To close and reattach the panel, reverse the procedures

listed above.

Note: To secure panel in open position during service

procedures, attach chain mounted to cabinet frame
behind the unit center cover panel to chain retainer
notch on the edge of the VFD panel.

Note: Verify all wires are in proper position and not

rubbing before replacing the panel.

Note: Panel weight rating = 225 lbs. total, including

factory-installed components.

Variable Frequency Drive (VFD) - Remote

Mounted

ReferenceTR200 operating instructions (BAS-SVX19A­EN) for maintenance information on VFD.

Air Filters

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors. Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect power
and discharge capacitors before servicing could result
in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

Filter access doors are on the unit’s left side. Filter access
for the 2” filter rack on optional steam and hot water coils
and airside economizers is also on the left side of the unit.

To replace throwaway filters, remove the dirty elements

and install new filters with the filter’s directional arrows
pointing toward the fan. Verify that no air bypasses the
filters.

Inspecting and Cleaning Drain Pan

Check the condensate drain pan and drain line to ensure
that the condensate drains properly at least every six
months or as dictated by operating experience.

90 SCXG-SVX01H-EN

Maintenance

If evidence of standing water or condensate overflow
exists, take steps to identify and remedy the cause
immediately. See “Troubleshooting,” p. 104 for possible
causes and solutions.

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives or
other energy storing components provided by Trane or
others, refer to the appropriate manufacturer’s literature
for allowable waiting periods for discharge of
capacitors. Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect power
and discharge capacitors before servicing could result in
death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

Clean drain pans using the following procedure:

1. Disconnect all electrical power to the unit.

2. Don the appropriate personal protective equipment
(PPE).

3. Remove all standing water.

4. Use a scraper or other tools to remove and solid
matter. Remove solid matter with avacuum device that
utilizes high efficiency particulate arrestance (HEPA)
filters with a minimum efficiency of 99.97% at 0.3
micron particle size.

5. Thoroughly clean the contaminatedarea(s) with amild
bleachand water solution oran EPA-approved sanitizer
specifically designed for HVAC use. Carefully follow
the sanitizer manufacturer’s instructions regarding
product use.

6. Immediately rinse drain pan thoroughly with fresh
water to prevent potential corrosion from cleaning
solution.

7. Allow the unit to dry thoroughly before putting the
system back into service.

8. Properly dispose of all contaminated materials and
cleaning solution.

Inspecting and Cleaning the Fan

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors.Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect
power and discharge capacitors before servicing could
result in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

Inspect the fan section every six months or more
frequently if operating experience dictates. Clean
accumulated dirt and organic matter on the fan interior
surfaces following the procedure below:

1. Disconnect all electrical power to the unit.

2. Wear the appropriate personal protective equipment
(PPE).

3. Use a portable vacuum with HEPA filtration to remove
the loose dirt and organic matter.The filter should be

99.97% efficient at 0.3 micron particle size.

4. Thoroughly clean the fan and associated components
with an industrial cleaning solution. Carefully follow
the cleaning solution manufacturer’s instructions
regarding personal protection and ventilation when
using their product.

5. Rinse the affected surfaces thoroughly with fresh
water and a fresh sponge to prevent potential
corrosion of metal surfaces.

6. Allow the unit to dry completely before putting it back
into service.

7. Properly dispose of all contaminated materials and
cleaning solution.

Supply Fan

Fan Drive

Perform the following procedures according to the

“Periodic Maintenance Check List”.

SCXG-SVX01H-EN 91

Maintenance

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives or
other energy storing components provided by Trane or
others, refer to the appropriate manufacturer’s literature
for allowable waiting periods for discharge of
capacitors. Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect power
and discharge capacitors before servicing could result in
death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

1. Rotate the fan wheel to ensure it turns freely in the
proper direction and is not rubbing on the fan housing
or inlet. If necessary, center the fan wheel again.

2. Check the position of both shafts. Fan and motor shafts
should operate parallel to each other for maximum belt
and bearing life. Shim as necessary under the motor or
fan bearings to obtain proper alignment.

3. Check the fan motor sheave alignment with straight
edge or a tightly pulled string. For sheaves of different
widths, place a string in the center groove of each
sheave and pull it tight for a center line. See

p. 94 for recommended torques.

4. Once sheaves are properly aligned, tighten sheave set
screws to proper torque. See

Table 53 and Table 54,

p. 93.

5. Check belt tension. See “Measuring BeltTension,”

p. 93.

6. If required, adjust belt to the minimum recommended
tension. See

“Adjusting Belt Tension,” p. 94.

7. After aligning sheaves, retighten bearingset screws to
proper torques shown in

Table 53, p. 93 and Table 54,

p. 93 .

Figure 64,

8. Check the fan bearing locking collars for tightness on
the shaft.To tighten the locking collar, loosen the set
screw and slide the collar into its proper position over
the extended end of the inner case.Tighten the set
screw to torque value in

Table 53, p. 93 and Table 54,

p. 93.

9. During air balancing, verify the sheave alignment, belt
tension, and that the shaft is parallel.

Figure 63. Fan shaft and motor sheave alignment

For uneven width sheaves
use a taut string down the
center of both sides.

Fixed

Straight­edge

Sheave

Fan Bearings

The opposite drive end bearing is a special bearing with

close tolerance fit of balls and races. Replace this bearing
with the same part number as the original bearing. Follow
the fan bearing lubrication schedules in Table 50, p. 92,

Table 51, p. 92, andTable 52, p. 93 toreference compatible

fan bearing grease for specific bearings.

NOTICE:

Bearing Failure!

Do not mix greases with different bases within the
bearing. Mixing grease within the bearing could result
in premature bearing failure.

Table 50. Baldor fan bearing lubrication schedule

Baldor Rated Speed, rpm

NEMA/ (IEC) Frame Size 3600 1800 1200 900

up to 210 incl. (132) 5500 hrs 12,000 hrs 18,000 hrs 22,000 hrs

over 210 to 280 incl. (180) 3600 hrs 9500 hrs 15,000 hrs 18,000 hrs

over 360 to 5800 incl. (300) 2200 hrs 3500 hrs 7400 hrs 10,500 hrs

Table 51. AO smith bearing lubrication schedule

Speed Service Frame Standard Service Severe Service Extreme

Over 1800 rpm All 6 months 3 months 3 months

1800 rpm 140-180 3 yrs 1 yr 6 mths

210-280 2 1/2 yrs 10 1/2 mths 5 1/2 mths
320-360 2 yrs 9 mths 4 1/2 mths

92 SCXG-SVX01H-EN

Maintenance

Table 51. AO smith bearing lubrication schedule

Speed Service Frame Standard Service Severe Service Extreme

Over 1800 rpm All 6 months 3 months 3 months

400-440 1 1/2 yrs 8 mths 4 mths

Note: Service standard - 8 hrs/day , normal to lgith loading, 100°F ambient temp. max.Severe service - 24 hrs/day, shock loading, vibration, dirt or dust,

100 to 150°F ambient temp. Extreme service - heavy shock or vibration, dirt or dust, 100 to 150°F ambient temp.

Table 54. Fan hub and sheave torques

Table 52. Compatible fan bearing grease

Type

Texaco Multi Fak 2

Shell Alvania 2

Mobile 532

Chevron Dura-Lith 2

Exxon Beacon
Keystone 84H

Fan BeltTension

Note: Check fan belt tension at least twice during the first

days of new belt operation since there is a rapid
decrease in tension until belts are run-in.

Proper belt tension is necessary to endure maximum
bearing and drive component life and is based on fan
brake horsepower requirements. If frayed orworn, replace
belts in matched sets.

Measuring BeltTension

Measure fan belt tension with a Browning, Gates, or
equivalent belt tension gauge. Determine deflection by
dividing the belt span distance (in inches) by 64. See

Figure 64, p. 94. Follow the procedure below to measure

belt tension.

1. Measure belt span between centers of sheaves and set
the large “O” ring of the tensioning gauge at 1/64 inch
for each inch of belt span.

2. Set the load “O” ring at zero.

3. Place the large end of thegauge at thecenter of the belt
span. Press down until the large “O” ring is even with
the top of the belt line or the next belt as in

p. 94. Place a straight edge across the sheaves as a

reference point. See Figure 63, p. 92.

4. Remove the gauge. Note that the load “O” ring now
indicates a number on the plunger scale.This number
represents pounds of force required to deflect the belt.

5. Check the reading from step 4 against the values given
in

Table 53, p. 93. If necessary, readjust belt tension.

Figure 64,

unit size fan dia. setscrew size

SCWG 20
SCWG 22
SCWG 25
SCRG 20
SCWG 29
SCWG 32
SCRG 25
SCRG 30
SCWG 35
SCWG 38
SCRG 30
SCRG 35
SCWG 42
SCWG 46
SCWG 52
SCWG 58
SCRG 40
SCRG 50
SCWG 65
SCWG 72
SCWG 80
SCRG 60
SCWG 90
SCWG C0
SCWG C1

16.5” 5/16” 12

18” 5/16” 12

20” 5/16” 14

25” 3/8” 24

27” 3/8” 24

torque (ft-

lbs)

Table 53. Fan shaft bearing torques

Setscrew

size

1/4"-20 1/8” 180 15
5-16"-18 5-32” 402 33.5

SCXG-SVX01H-EN 93

hex-size across

flats recommended torque

In-lb ft-lb

Maintenance

Figure 64. Belt tension gauge (top) and fan belt

adjustment (bottom)

2. Loosen nuts C and D (as required for motor
horsepower) to slide the motor on its mounting plate
in the proper direction to tension or relieve tension on
the belt.

3. Adjust nutsA-D andbolt E. Do notstretch the belts over
the sheaves.

4. Retighten all nuts and bolts.

5. Verify tension is adjusted properly.

Recommended belt tension range values are on the unit
fan scroll.To access the fan scroll, face the right-hand side
of the unit and remove the top left panel.The belt tension
label is on the top right-hand corner of the fan scroll. See

Figure 65, p. 94.

The correct operation tension for a V-belt drive is the

lowest tension atwhich the belt will not slipunder the peak
load conditions. It may be necessary to increase the
tension of some drives to reduce flopping or excessive
startup squealing.

Figure 65. Location of fan belt label on fan scroll (top)

and belt tensioning with fan adjustment
points (bottom)

Adjusting BeltTension

NOTICE:

Belt Tension!

Do not over-tension belts. Excessive belt tension will
reduce fan and motor bearing life, accelerate belt wear
and possibly cause shaft failure.

To adjust belt tensionrefer to Figure 64, p. 94 and perform

the following procedure:

1. Loosen bolts A, B, and E on both sides of the sliding
motor base. See Figure 65, p. 94.

94 SCXG-SVX01H-EN

Figure 66. Fan assembly

Maintenance

Refrigerant System

Should refrigerant system repair be required, LeakTest,
Brazing and Evacuation Procedures are described.

Preliminary Charging is described in the Installation­Mechanical section, “Preliminary Refrigerant Charging,”

p. 37 and Final Charging is described in Start-up section,
“Final Refrigerant Charge,” p. 87.

Ignore Air Cooled Only steps for Water Cooled systems.

Refrigerant systems that have been opened must have
filter driers replaced and complete leak test and
evacuation before recharging.

Refrigerant LeakTest Procedure

WARNING

Confined Space Hazards!

Do not work in confined spaces where refrigerant or
other hazardous, toxic or flammable gas may be
leaking. Refrigerant or other gases could displace
available oxygen to breathe, causing possible
asphyxiation or other serious health risks. Some gases
may be flammable and or explosive. If a leak in such
spaces is detected, evacuate the area immediately and
contact the proper rescue or response authority. Failure
to take appropriate precautions or to react properly to
such potential hazards could result in death or serious
injury.

WARNING

Hazard of Explosion!

Never use an open flame to detect gas leaks. It could
result in an explosion. Use a leak test solution for leak
testing. Failure to follow recommended safe leak test
procedures could result in death or serious injury or
equipment or property-only-damage.

WARNING

Hazard of Explosion!

Use only dry nitrogen with a pressure regulator for
pressurizing unit. Do not use acetylene, oxygen or
compressed air or mixtures containing them for
pressure testing. Do not use mixtures of a hydrogen
containing refrigerant and air above atmospheric
pressure for pressure testing as they may become
flammable and could result in an explosion.
Refrigerant, when used as a trace gas should only be
mixed with dry nitrogen for pressurizing units. Failure
to follow these recommendations could result in death
or serious injury or equipment or property-only
damage.

WARNING

Hazardous of Explosion!

Do not exceed unit nameplate design pressures when
leak testing system. Failure to follow these instructions
could result in an explosion causing death or serious
injury.

SCXG-SVX01H-EN 95

Maintenance

WARNING

R-410A Refrigerant under High Pressure!

The units described in this manual use R-410A

refrigerant. Use ONLY R-410A rated service equipment
or components with these units. For specific handling
concerns with R-410A, please contact your localTrane
representative. Failure to use R-410A rated service
equipment or components could result in equipment
exploding under R-410A high pressures which could
result in death, serious injury, or equipment damage.

Note: These service procedures require working with

refrigerant. Do not release refrigerant to the
atmosphere!The service technician must comply
with all federal, state, and local laws.

When Leak-testing refrigerant systems, observe all safety

precautions.

Leak test only one circuit at a time to minimize system
exposure to potentially harmful moisture in the air.

Field Piping (air cooled discharge and liquid
lines)

1. Ensure all required field installed piping pressure tests
are completed inaccordance with nationaland/or local
codes.

2. Close liquid line angle valve.

3. Connect R-410A refrigerant cylinder to high side
charging port (at Remote Condenser or field supplied
discharge line access port). Add refrigerant to reach
pressure of 12 to 15 psig.

4. Disconnect refrigerant cylinder. Connect dry nitrogen
cylinder to high side charging port and increase
pressure to 150 psig. Do not exceed high side
(discharge) unit nameplate design pressure. Do not
subject low side (suction) components to high side
pressure.

5. Check all piping joints, valves, etc. for leaks.
Recommend using electronic detector capable of
measuring 0.1 oz/year leak rate.

6. If a leak is located, use proper procedures to remove
the refrigerant/nitrogen mixture, break connections
and make repairs. Retest for leaks.

Make sure all service valves are open.

System Repair

1. If system is water cooled with service valves, or air
cooled, high and low side may be tested independently
by closing liquid line angle valve and water cooled unit
discharge line ball valve. Otherwise leave all valves
open and DO NOT exceed low side design pressure.

2. Connect R-410A refrigerant cylinder to charging port,
add refrigerant to reach pressure of 12 to 15 psig.

3. Disconnect refrigerant cylinder. Connect dry nitrogen
cylinder to high side charging port and increase
pressure to 150 psig. DO NOT exceed unit nameplate

design pressures. If testing complete system, low side
design pressure is maximum.

4. Check piping and/or components as appropriate for
leaks.

5. Recommend using electronic detector capable of
measuring 0.1 oz/year leak rate.

6. If a leak is located, use proper procedures to remove
the refrigerant/nitrogen mixture, break connections
and make repairs. Retest for leaks.

7. Make sure all service valves are open.

Brazing Procedures

WARNING

Hazard of Explosion and Deadly Gases!

Never solder, braze or weld on refrigerant lines or any
unit components that are above atmospheric pressure
or where refrigerant may be present. Always remove
refrigerant by following the guidelines established by
the EPA Federal Clean Air Act or other state or local
codes as appropriate. After refrigerant removal, use dry
nitrogen to bring system back to atmospheric pressure
before opening system for repairs. Mixtures of
refrigerants and air under pressure may become
combustible in the presence of an ignition source
leading to an explosion. Excessive heat from soldering,
brazing or welding with refrigerant vapors present can
form highly toxic gases and extremely corrosive acids.
Failure to follow all proper safe refrigerant handling
practices could result in death or serious injury.

Proper brazing techniques are essential when installing
refrigerant piping.The following factors should be kept in
mind when forming sweat connections.

1. When heating copper in the presence of air, copper
oxide forms.To prevent copper oxide from forming
inside the tubing during brazing, sweep an inert gas,
such as dry nitrogen, through the tubing. A nitrogen
flow of 1 to 3 cubic feet per minute is sufficient to
displace the air in the tubing and prevent oxidation of
the interior surfaces. Use a pressure regulating valve
or flow meter to control the flow.

2. Ensure that the tubing surfaces requiring brazing are
clean, and that the tube ends are carefully reamed to
remove any burrs.

3. Make sure the inner and outer tubes of the joint are
symmetrical and have a close clearance, providing an
easy ‘slip’ fit. If the joint is too loose, the connection’s
tensile strength is significantly reduced. Ensure the
overlap distance is equal to the inner tube diameter.

4. Wrap each refrigerant line component with a wet cloth
to keep it cool during brazing. Excessive heat can
damage the internal components.

Note: Use 40-45% silver brazing alloy (BAg-7 or BAg-28)

on dissimilar metals. Use BCup-6 brazing alloy on
copper-to-copper joints.

96 SCXG-SVX01H-EN

NOTICE:

Valve Damage!

Remove, do not wrap, water cooled condenser pressure
relief valves during brazing. Failure to do so could result
in valve damage.

Maintenance

Install electronic micron vacuum gauge in common line
ahead of vacuum pump shutoff valve, as shown in

Figure 67, p. 98. Close valves B and C, open valve A.

Start vacuum pump.After several minutes, gauge reading
will indicate maximum vacuum pump is capable of
pulling. Rotary pumps should produce vacuums of 100
microns or less.

5. If using flux, apply sparingly to joint. Excess flux will
contaminate refrigerant system.

6. Apply heat evenly over length and circumference of
joint.

7. Begin brazing when the joint is hot enough to melt the
brazing rod.The hot copper tubing, not the flame,
should melt the rod.

8. Continue to apply heat evenly around the joint
circumference until the brazing material is drawn into
the joint by capillary action, making a mechanically
sound and gas-tight connection.

9. Visually inspect the connection after brazing to locate
any pinholes or crevices in the joint. Use a mirror if
joint locations are difficult to see.

System Evacuation Procedures

Each refrigeration circuit must be evacuated before the
unit can be charged and started.

Use a rotary type vacuum pump capable of pulling a
vacuum of 100 microns or less.

Verify that the unit disconnect switch and the system

control circuit switches are “OFF”.

Oil in the vacuum pump should be changed each time the
pump is used with high quality vacuum pump oil. Before
using any oil, check the oil container for discoloration
which usually indicates moisture in the oil and/or water
droplets. Moisture in the oil adds to what the pump has to
remove from the system, making the pump inefficient.

When connecting the vacuum pump to a refrigeration

system, it is important to manifold the vacuum pump to
both the high and low side of the system (liquid line access
valve and suction line access valve). Follow pump
manufacturer’s directions for proper usage methods.

Lines used to connect the pump to the system should be
copper and of the largest diameter that can practically be
used. Using larger line sizes with minimumflow resistance
can significantly reduce evacuation time.

Important: Rubber or synthetic hoses are not

recommended for system evacuation
because they have moisture absorbing
characteristics which result in excessive
rates of evaporation, causing pressure rise
during the standing vacuum test.This
makes it impossible to determine if the
system has a leak, excessive residual
moisture, or a continual or high rate of
pressure increase due to the hoses.

NOTICE:

Motor Winding Damage!

Do not use a megohm meter or apply voltage to a
compressor motor winding while it is under a vacuum.

Voltage sparkover could cause damage to the motor

windings.

OpenValves B and C. Evacuate the system to a pressure of
300 microns or less. As the vacuum is being pulled on the
system, there couldbe a time when it wouldappear that no
further vacuum is being obtained, yet thepressure is high.
It is recommended that during the evacuation process,the
vacuum be “Broken”, to facilitate the evacuation process.

To break the vacuum, shut valves A, B, & C and connect a

refrigerant cylinder to the charging port on the manifold.
Purge the air from the hose. Raise the standing vacuum
pressure in the system to “zero” (0 psig) gauge pressure.
Repeat this process two or three times during evacuation.

Note: It is unlawful to release refrigerant into the

atmosphere. When service procedures require
working with refrigerants, the service technician
must comply with all Federal, State, and local laws.

Standing VacuumTest . Once 300 microns or less is

obtained, close Valve A, leave valves B and C, allowing
vacuum gauge to read actual system pressure. Let system
equalize for approximately 15 minutes.This is referred to
as a “standing vacuum test” where, time versus pressure
rise. Maximum allowable rise in 15 minutes is 200
microns. If pressure rise is greater than 200 microns but
levels off to a constant value, excessive moisture is
present. If pressure steadily continues to rise, a leak is
indicated. Figure 68, p. 98 illustrates three possible results
of the “standing vacuum test”.

If a leak is encountered, repair system and repeat
evacuation process until recommended vacuum is
obtained. Once the system has been evacuated, break the
vacuum with refrigerant and complete the remaining Pre­Start procedures before starting the unit.

SCXG-SVX01H-EN 97

Maintenance

Figure 67. Typical vacuum pump hookup

Figure 68. Evacuation time vs. pressure rise

Compressors

Scroll Compressor Failure Diagnosis and Replacement

If compressor failure is suspected, refer to COM-SVN01A­EN for detailed information regarding compressor failure
diagnosis and replacement of scroll compressors.

98 SCXG-SVX01H-EN

Components

Figure 69. Typical water-cooled (SXWG) compressor section components

Maintenance

Important: On units ordered with a Design Special of Inlet Guide Vanes, refer to non-current IOM (SCXF-SVX01D-EN)

dated on or before March 2008 for maintenance procedure.

SCXG-SVX01H-EN 99

Maintenance

Coil Fin Cleaning

WARNING

Hazardous Chemicals!

Coil cleaning agents can be either acidic or highly
alkaline and can burn severely if contact with skin
occurs. Handle chemical carefully and avoid contact
with skin. ALWAYS wear Personal Protective
Equipment (PPE) including goggles or face shield,
chemical resistant gloves, boots, apron or suit as
required. For personal safety refer to the cleaning agent
manufacturer’s Materials Safety Data Sheet and follow
all recommended safe handling practices. Failure to
follow all safety instructions could result in death or
serious injury.

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors.Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect
power and discharge capacitors before servicing could
result in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

NOTICE:

Equipment Damage!

Do not clean the refrigerant coil with hot water or
steam.The use of hot water or steam as a refrigerant
coil-cleaner agent could cause high pressure inside the
coil tubing and subsequent damage to the coil.
Do not use acidic chemical coil cleaners. Also, do not
use alkaline chemical coil cleaners with a pH value
greater then 8.5 (after mixing) without using an
aluminum corrosion inhibitor in the cleaning solution.
Use of the chemical could result in equipment damage.

Keep coils clean to maintain maximum performance. For
operation at itshighest efficiency,clean the refrigerantcoil
often during periods of high cooling demandor when dirty
conditions prevail. Clean the coil a minimum of once per
year to prevent dirt buildup in the coil fins, where it may
not be visible.

Remove large debris from the coils and straighten fins
before cleaning. Remove filters before cleaning.

Clean refrigerant coils with cold water and detergent, or
with one of the commercially available chemical coil
cleaners. Rinse coils thoroughly after cleaning.

Economizer and evaporator coils are installed so the
evaporator is directly behind the economizer. To clean
between the coils, remove the sheet metal block off.

Access the block off by removing the corner panels on the

unit’s left or right rear side.

If the refrigerant coil is installed back to back with the
waterside economizer coil,use a cleaner that is acceptable
for cleaning both types of coils.

Inspecting and Cleaning Coils

Coils become externally fouled as a result of normal
operation. Coil surface dirt reduces heat transfer ability
and can cause comfort problems, increased airflow
resistance and thus increased operating energy costs.

Inspect coils at least every six months or more frequently
as dictated by operating experience. Cleaning frequently
is dependent upon system operating hours, filter
maintenance, efficiency, and dirt load. Following is the
suggested method for cleaning steam and hot water coils.

Steam and Hot Water Coils

WARNING

Hazardous Voltage w/Capacitors!

Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives
or other energy storing components provided by Trane
or others, refer to the appropriate manufacturer’s
literature for allowable waiting periods for discharge of
capacitors.Verify with an appropriate voltmeter that all
capacitors have discharged. Failure to disconnect
power and discharge capacitors before servicing could
result in death or serious injury.

For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN

1. Disconnect all electrical power to the unit.

2. Wear appropriate personal protective equipment
(PPE).

3. Access both sides of the coil section.

4. Use a soft brush to remove loose debris from both
sides of the coil.

5. Use asteam cleaning machine, starting fromthe top of
the coil and working downward. Clean the leaving air
side of the coil first, then the entering air side. Use a
block-off to prevent steam from blowing through the
coil and into a dry section of the unit.

6. Repeat step 5 as necessary. Confirm that the drain line
is open following completion of the cleaning process.

7. Allow the unit to dry thoroughly before putting the
system back into service.

8. Straighten any coil fins that may be damaged with a fin
rake.

100 SCXG-SVX01H-EN