McQuay RCS 025D Installation Manual
Installation and Maintenance Manual IM 893-1
RoofPak™ Singlezone Roof Mounted
Heating and Cooling Units
RPS/RDT/RFS/RCS 015D – 140D
R-410A Refrigerant and MicroTech® III Unit Controller
Group: Applied Systems
Part Number: IM 893
Date: November 2009
Contents
Introduction .............................................................. 3
Unit Nameplate ................................................... 3
Compressor Nameplate...................................... 3
Gas Burner Nameplate ....................................... 3
Hazard Identification Information ........................ 3
Unit Description .................................................. 4
Refrigeration Piping ............................................ 6
Control Locations................................................ 7
Control Panel ...................................................... 9
Controls, Settings, and Functions..................... 16
Condenser Fan Arrangement ........................... 19
Mechanical Installation .......................................... 20
Unit Clearances ................................................ 20
Ventilation Clearance........................................ 21
Overhead Clearance......................................... 21
Roof Curb Assembly and Installation................ 22
Post and Rail Mounting..................................... 25
Rigging and Handling ....................................... 25
Reassembly of Split Units................................. 27
Unit Piping ........................................................ 35
Steam Coil Piping ............................................ 36
Damper Assemblies.......................................... 38
Cabinet Weather Protection.............................. 40
Installing Ductwork............................................ 40
Installing Duct Static Pressure Sensor Taps .... 41
Installing Building Static Pressure Sensor Taps 42
Electrical Installation ............................................. 43
Field Power Wiring............................................ 43
Field Control Wiring .......................................... 46
Preparing Unit for Operation ................................. 47
Spring Isolated Fans......................................... 47
Adjusting Spring Mounts................................... 47
Relief Damper Tie-Down .................................. 48
Adjustment of Seismic Restraints ..................... 48
Adjusting Scroll Dampers ................................. 48
Adjusting Supply Fan Thrust Restraints ........... 49
Sequences of Operation ........................................ 50
Power-up .......................................................... 50
Fan Operation................................................... 50
Economizer Operation ...................................... 51
Mechanical Cooling Operation.......................... 51
Heating ............................................................. 52
MicroTech III Controller Operation ....................... 53
Using the Keypad/Display................................. 53
Passwords ........................................................ 53
Navigation Mode............................................... 54
Edit Mode ......................................................... 54
Wiring Diagrams ..................................................... 55
Unit Options ............................................................ 73
Control Actuators .............................................. 73
Enthalpy Control ............................................... 73
Modulating Hot Gas Reheat ............................. 75
Hot-Gas Bypass (HGBP) .................................. 77
External Time Clock.......................................... 77
Smoke and Fire Protection ............................... 77
Smoke Detectors .............................................. 78
Emergency Shutdown ...................................... 78
Freeze Protection............................................. 78
Field Output Signals......................................... 79
Entering Fan Temperature Sensor................... 80
Duct High Pressure Limit ................................. 80
Variable Frequency Drive Operation ................ 80
Convenience Receptacle/Section Lights.......... 80
Optional Low Ambient Compressor
Operation ......................................................... 81
Variable Frequency Drive Operation ................ 82
Convenience Receptacle/Section Lights.......... 82
DesignFlow™ Outdoor Air Damper Option ...... 82
Propeller Exhaust Fan Option .......................... 85
Exhaust Fan On/Off Control............................. 88
Ultraviolet Lights Option ................................... 88
Check, Test, and Start Procedures ...................... 92
Servicing Control Panel Components .............. 92
Before Start-up................................................. 92
Power Up ......................................................... 92
Fan Start-up ..................................................... 93
Economizer Start-up ........................................ 93
Compressor Startup ......................................... 93
Scroll Compressor Rotational Direction ........... 94
Heating System Startup ................................... 95
Air Balancing .................................................... 96
Sheave Alignment ............................................ 96
Drive Belt Adjustment....................................... 96
Mounting and Adjusting Motor Sheaves .......... 97
Final Control Settings.......................................... 100
Maintenance ......................................................... 104
Servicing Control Panel Components ............ 104
Planned Maintenance .................................... 104
Unit Storage ................................................... 104
Gas Furnace .................................................. 105
Bearing Lubrication ........................................ 105
Propeller Exhaust Fan.................................... 107
Setscrews....................................................... 107
Supply Fan Wheel-to-Funnel Alignment ........ 108
Scroll Compressor Piping............................... 110
All-Aluminum Condenser Coils ...................... 111
Refrigerant Charge......................................... 112
Servicing Refrigerant Sensors or Switches.... 112
Winterizing Water Coils.................................. 112
Control Panel Components ............................ 113
Replacement Parts List ....................................... 117
Service and Warranty Procedure ....................... 118
Replacement Parts......................................... 118
Scroll Compressor.......................................... 118
Replacing a Portion of a Tandem or Trio ....... 118
In-Warranty Return Material Procedure ......... 119
Limited Product Warranty (North America)....... 120
Exceptions...................................................... 120
Assistance...................................................... 120
Sole Remedy.................................................. 120
Rooftop Equipment Warranty Regist. Form ...... 121
Quality Assurance Survey Report...................... 124
Introduction
R P S – 080 D S E
RoofPak
Unit configuration
P = Heating, mechanical cooling
F = Heating, future mechanical cooling
C = Condensing section only
D = Draw through cooling
Blow through cooling = S
Draw through cooling = T
Heat medium
A = Natural gas
E = Electric
S = Steam
W = Hot water
Y = None (cooling only)
Design vintage
Nominal capacity (tons)
RPS, RFS, RCS, RDT: 015, 020, 025, 030, 035, 040, 042, 045, 050,
060, 062, 068, 070, 075, 080, 085, 090, 100, 105, 110, 120, 125, 130,
140
Cooling coil size
S=Standard (low airflow)
L =Large (high airflow)
This manual provides general information about the “D”
vintage McQuay RoofPak applied rooftop unit, models RPS,
RDT, RFS and RCS. In addition to an overall description of
the unit, it includes mechanical and electrical installation
procedures, commissioning procedures, sequence of operation
information, and maintenance instructions. For further
information on the optional forced draft gas-fired furnace,
refer to IM 684 or IM 685.
The MicroTech III applied rooftop unit controller is available
on “D” vintage applied rooftop units. For a detailed
description of the MicroTech III components, input/output
configurations, field wiring and information on using and
programming the MicroTech III unit controller, refer to OM
920.
For a description of operation and information on using the
keypad to view data and set parameters, refer to the
appropriate program-specific operation manual (see Figure 1).
Table 1: Program Specific Rooftop Unit Literature
Operation manual
number
VFDs
Rooftop unit control configuration
McQuay 208 - 460 V OM 844
McQuay 575 V OM 895
Non-McQuay See vendor manuals
Unit Nameplate
The unit nameplate is located on the outside lower right corner
on the main control box door. It includes the unit model
number, serial number, unit part number, electrical
characteristics, and refrigerant charge.
Introduction
Compressor Nameplate
On units that utilize the tandem compressor design, each
compressor includes an individual nameplate along with a
nameplate identifying the tandem compressors.
On units that utilize the trio compressor design, each
compressor includes an individual nameplate. There is no
nameplate identifying the trio compressors.
Gas Burner Nameplate
On units that include gas heat, the nameplate is located on the
lower right corner on the main control box door. It includes the
burner model number, minimum/maximum input, maximum
temperature rise, and minimum CFM.
Hazard Identification Information
DANGER
Dangers indicate a hazardous situation which will result in
death or serious injury if not avoided.
WARNING
Warnings indicate potentially hazardous situations, which can
result in property damage, severe personal injury, or death if
not avoided.
CAUTION
Cautions indicate potentially hazardous situations, which can
result in personal injury or equipment damage if not avoided.
Figure 1: Nomenclature
McQuay IM 893-1 3
Introduction
RPS/RDT
Unit Description
Figure 2: RPS/RDT/RFS/RCS Unit
Typical Component Locations
Figure 2 shows an RPS/RDT/RFS/RCS unit. Figure 3 shows a
typical RPS unit with the locations of the major components.
Figure 4 on page 5 shows a typical RDT unit with the locations
of the major components. These figures are for general
information only. See the project’s certified submittals for
actual specific dimensions and locations.
Figure 3: Typical Component Locations—RPS Units
1.5" NPT Drain
Condenser
control panel
(RCS only)
4 McQuay IM 893-1
Figure 4: Component Locations—RDT Units
1.5 NPT drain
Introduction
McQuay IM 893-1 5
Introduction
O
A Compressor (1, 2, or 3 per circuit) †
B Discharge line †
C Condenser coil †
D Evaporator coil *
E Manual shutoff valve †
F Filter-drier †
H Sightglass †
I Liquid line *†
J Suction line *†
K Thermal expansion valve *
L Distributor *
M Drop solenoid valve *
N Hot gas bypass valves (optional) *
O Hot Gas bypass piping (optional) *†
*Supplied on RFS units
†Supplied on RCS units
Refrigeration Piping
This section presents the unit refrigeration piping diagrams for
the various available configurations.
Figure 5: Circuit Schematic
Figure 6: Condenser Piping, Scroll Compressors, 2 to 3 Compressors per Circuit are Provided (6 Compressors Shown)
6 McQuay IM 893-1
Control Locations
R eturn air
economizer
Filter
se ction
Supply
fan
Heat
DX
se ction
Discharge
plenum
se ction
Condensor
se ction
RAT
LT11
(optio na l)
S11,
REC11
OAE
ACT 3
PC5
S10, R EC10
LT10
HL22
EFT
SD1
VM1
DAT
ACT5 (optional)
HT R 1-2, HTR3-4 (optional)
(optional)
(optional)
(optional)
(optional)
(optional)
se ction
se ction
FS1
(optional)
C19
OAT
AC T6 (optional)
RAE (optional)
SD2
(optional)
PC7
C11, 12
(optional)
SC11, 12
(optional)
Introduction
Figure 7 (RPS Units) and Figure 8 on page 8 (RDT Units)
show the locations of the various control components mounted
throughout the units. See “Control Panel” on page 9 for the
locations of control components mounted in control panels.
Figure 7: Control Locations—RPS units
Additional information is included in Table 2 on page 16 and
the wiring diagram legend, which is included in “Wiring
Diagrams” on page 55.
McQuay IM 893-1 7
Introduction
Economizer
Filter
DX
Heat
section
Supply fan
discharge
plenum
section
Condenser
C19, 20
RAT
LT11 (optional)
S11, REC11
SD2
RAE
ACT3
PC5
OAE
VM1
LT10 (optional)
DAT
OAT
SC11, 21
(optional)
C11, 21
(optional)
(optional)
HTR3-4 (optional)
section
section
section
return air
(optional)
(optional)
(optional)
(optional)
C9
FS1
(optional)
HTR1-2, U1/U2
S10, REC10 (optional)
SD1 (optional)
ACT6
Figure 8: Control Locations—RDT Units
8 McQuay IM 893-1
Control Panel
Prop exhaust/ return fan
Introduction
The unit control panels and their locations are shown in the
following figures. These figures show a typical unit
configuration. Specific unit configurations may differ slightly
Figure 9: Control Panel Locations
from these figures depending on the particular unit options.
See “Wiring Diagrams” on page 55 for the legend and
component description.
McQuay IM 893-1 9
Introduction
Figure 10: Typical Main Control Panel, 045D to 075D, 460 Volt
10 McQuay IM 893-1
Figure 11: Typical Main Control Panel, 080D to 140D, 460 Volt
Introduction
McQuay IM 893-1 11
Introduction
S3
FSG
FSG Time
LS1
LS2
AS
IT
TD10
R22
R20
R23 R21
TB11
AFD20 GND
M51 M52 M53
Figure 12: Typical Gas Heat Panel, 1000 MBh (High TD) Figure 13: Typical Prop Exhaust Panel, 3 Fans, 460 Volt
Figure 14: VFD Bypass Panel, 40 HP, 460 Volt
12 McQuay IM 893-1
Figure 15: RCS Control Panel with MicroTech III, RPS 045D to 075D
Figure 16: RCS Control Panel with MicroTech III, RPS 080D to 140D
Introduction
McQuay IM 893-1 13
Introduction
GLG3
DS3
M41M43
FB41FB42FB43
H53
TB11
M31M32M33
FB31FB32FB33
M42
GLG3
DS3
M41M42M43
FB41FB42FB43
H53
TB11
M34M44
M31M32M33
FB31FB32FB33
FB34FB44
Figure 17: Electric Heat Panel, Sizes 045D to 75D Figure 18: Electric Heat Panel, Sizes 080D to 140D
14 McQuay IM 893-1
Figure 19: Harness Plug Connector Detail
LT OP1 LT OP2
LT11LT1 0
COMP6COMP5
COMP3 COMP4
COMP1 COMP2
DFRH DFLH OPEN4
SD1 SD2
GSHT1 GSHT2
HL22 OPEN3
OAE PC7PC5
ACT3 OPEN2
SV12 SV56
AFD10 AFD20
FP1 OPEN1EPTS
RATS OATSDATS
Introduction
McQuay IM 893-1 15
Introduction
Controls, Settings, and Functions
Table 2 below lists all of the unit control devices. Included in
the table are the device symbol, a description of the device, its
function, and any reset information, its location, any device
setting, any setting ranges, differentials, and the device part
number.
Table 2: Controls, Settings, and Functions
Symbol Description Function Reset Location Setting Range Differential Part no.
CS1 & 2 Switch (toggle),
refrigerant circuit
DAT Discharge air
temperature
sensor
DHL Duct high limit
switch
EFT Entering fan air
temperature
sensor
FP1, 2 Frost protection Senses DX coil temperature
FS1 Freezestat Shuts off fans, opens heating
HP1, 2 High pressure
control
LP1, 2 Low pressure
control
MCB Main control board Processes input information N/A Main control
MP1–6 Compressor
motor protector
OAE Enthalpy control
(electromechanical)
Enthalpy control
(electronic)
OAT Outside air
temperature
sensor
PC5 Dirty filter switch Senses filter pressure drop Auto First filter
PC6 Dirty filter switch Senses filter pressure drop Auto Final filter
PC7 Airflow proving
switch
RAE Return air
enthalpy sensor
RAT Return air
temperature
sensor
Shuts off compressor control
circuits manually
Senses discharge air
temperature
Prevents excessive VAV duct
pressures; shuts off fan
Senses entering fan air
temperature
for frost protection
valve, and closes outdoor
damper if low air temperature
at coil is detected
Stops compressor when
refrigerant discharge pressure
is too high
Stops compressor when
suction pressure is too low
Senses motor winding
temperature, shuts off
compressor on high
temperature.
Returns outside air dampers to
minimum position when
enthalpy is too high
Returns outside air dampers to
minimum position when
outside air enthalpy is higher
than return air empalthy
(use RAE)
Senses outside air
temperature
Senses supply fan pressure to
prove airflow
Used to compare return air
enthalpy to outside air
enthalpy (used with OAE)
Senses return air temperature N/A Return air
N/A Main control
N/A Discharge air
Auto Main control
N/A Inlet of supply
Auto DX coil 30° +/- 6° open
Auto Heating
Manual
(relay
latched)
Auto Compressor See page 112. N/A 45 psi with low
Auto at
3400
ohms
Auto Economizer
Auto Economizer
N/A N/A N/A 060004705
Auto Supply fan
N/A Economizer
panel
section
panel
fan
section
Compressor See page 112. N/A 150 psi 403585001
box
Compressor
junction box
section
section
section
section
section
section
section
N/A N/A N/A 01355000
N/A N/A 060004705
3.5" w.c
(871.8 Pa)
N/A N/A 060004705
45° +/- 6° close
38°F (3°C)
or as required
N/A N/A N/A 060006101
9 K–18 K ohms 700 ohms cold N/A 044691509
“B” or as required A–D Temperature:
Fully CW past “D”
(when used
with RAE)
As required .05-5" w.c.
As required .05-5" w.c.
.10" w.c. (25 Pa) .05-5" w.c.
N/A N/A N/A 049262202
N/A N/A 060004705
0.05–5.0" w.c.
(12.5–1245.4 Pa)
N/A 15° 113073401
35°F–45°F
(2°C–7°C)
A–D N/A 049262201
(12.5–1245.4 Pa)
(12.5–1245.4 Pa)
(12.5–1245.4 Pa)
.05" w.c.
(12.5 Pa), fixed
12°F (7°C),
fixed
amb. option
/50 psi
3.5°F (2°C)
Humidity:
5% fixed
.05" w.c.
(12.5 Pa)
.05" w.c.
(12.5 Pa)
.05" w.c.
(12.5 Pa), fixed
065493801
065830001
403585501/
403585101
030706702
065493801
065493801
060015801
16 McQuay IM 893-1
Introduction
Table 2: Controls, Settings, and Functions (continued)
Symbol Description Function Reset Location Setting Range Differential Part no.
SD1 Smoke detector,
supply air
SD2 Smoke detector,
return air
SPS1 Static pressure
sensor duct #1
SPS2 Static pressure
sensor duct #2
Static pressure
sensor: building
(space) pressure
S1
System switch
S7 ON-OFF-AUTO
switch
SV1-2 Drop solenoid Shuts liquid line when
FanTrol
The FanTrol, provided on all units, is a method of head
pressure control that automatically cycles the condenser fans
in response to ambient air temperature. This feature maintains
head pressure and allows the unit to run at low ambient air
temperatures.
Initiates unit shutdown if
smoke is detected
Initiates unit shutdown if
smoke is detected
Converts static pressure
signals to voltage signals
Converts static pressure
signals to voltage signals
Converts static pressure
signals to voltage signals.
Shuts off entire control circuit
(except crankcase heaters)
Used to manually switch unit N/A Main control
compressor is off
Manual Discharge air
section
Manual Return air
section
N/A Main control
box
N/A Main control
box
N/A Main control
box
N/A Main control
box
box
N/A Discharge air
section
RPS/RDT and RCS units have two independent refrigerant
circuits with one to four condenser fans being controlled
independently by the ambient air temperature of each circuit.
See the following sections for sequence of operation for
condenser fans with FanTrol.
N/A N/A N/A 04925001
N/A N/A N/A 04925001
N/A 0–5" w.c.
(0–1245.4 Pa)
1–6 V (dc) out
N/A 0–5" w.c.
(0–1245.4 Pa)
1–6 V (dc) out
N/A -025–0.25" w.c.
(-62.3–62.3 Pa)
1–5 V (dc) out
N/A N/A N/A 001355000
N/A N/A N/A
N/A N/A N/A 049266502
N/A 049545007
N/A 049545007
N/A 049545006
Table 3: R-410A FanTrol Setpoints in °F with MicroTech III Controls
Degrees Farenheit
Unit Size
Setpoint Differential Setpoint Differential Setpoint Differential
015D 70 5
020D 70 5
025D 60 5
030D 75 5
035D 70 5
040D 65 5
042D 65 5
045D 65 5
050D 65 5
060D 60 5
062D 70 5
068D 70 5
070D 75 5 90 35
075D6558559035
080D 75 5 90 35
085D 70 5 90 35
090D6058559035
100D6058559035
105D5058059035
110D6559059035
120D6558559035
125D6558559035
130D6058559035
140D5558059035
* PC13/23 Cut in = 450 psig (125 degree sat.)
Cut out = 275 psig (90 degree sat.)
D07 D08 PC13/PC23
1
McQuay IM 893-1 17
Introduction
Table 4: R-410A Fan Cycling Setpoints in °F with No Controls
RPS RCS
RDT RPR
015D TC12 65 70 5 TC12 Controls 1 Fan
020D TC12 65 70 5 TC12 Controls 1 Fan
025D TC12 55 60 5 TC12 Controls 1 Fan
030D TC12 70 75 5 TC12 Controls 1 Fan
035D TC12 65 70 5 TC12 Controls 1 Fan
040D TC12 60 65 5 TC12 Controls 1 Fan
042D TC12 60 65 5 TC12 Controls 1 Fan
045D TC12 60 65 5 TC12 Controls 1 Fan
050D TC12 60 65 5 TC12 Controls 1 Fan
060D TC12 55 60 5 TC12 Controls 1 Fan
062D TC12 65 70 5 TC12 Controls 1 Fan
070D TC12 65 70 5 TC12 Controls 1 Fan
075D TC12 60 65 5 TC12 Controls 1 Fan
080D TC12 70 75 5 TC12 Controls 1 Fan
090D TC12 55 60 5 TC12 Controls 1 Fan
100D TC12 55 60 5 TC12 Controls 1 Fan
110D TC12 60 65 5 TC12 Controls 1 Fan
120D TC12 60 65 5 TC12 Controls 1 Fan
125D TC12 60 65 5 TC12 Controls 1 Fan
140D TC12 50 55 5 TC12 Controls 1 Fan
* PC13/23 Cut in = 450 psig (125 degree sat.), cut out = 275 psig (90 degree sat.). PC13/23 setpoints are fixed.
Control ID
PC13/PC23 90 125 35 PC13/PC23 Controls 1 Fan*
TC14 80 85 5 TC14 Controls 1 Fan
PC13/PC23 90 125 35 PC13/PC23 Controls 1 Fan*
PC13/PC23 90 125 35 PC13/PC23 Controls 1 Fan*
TC14 80 85 5 TC14 Controls 1 Fan
PC13/PC23 90 125 35 PC13/PC23 Controls 1 Fan*
TC14 80 85 5 TC14 Controls 1 Fan
PC13/PC23 90 125 35 PC13/PC23 Controls 1 Fan*
TC14 85 90 5 TC14 Controls 1 Fan
PC13/PC23 90 125 35 PC13/PC23 Controls 1 Fan*
TC14 80 85 5 TC14 Controls 1 Fans
PC13/PC23 90 125 35 PC13/PC23 Controls 1 Fan*
TC14 80 85 5 TC14 Controls 1 Fan
PC13/PC23 90 125 35 PC13/PC23 Controls 1 Fan*
TC14 75 80 5 TC14 Controls 2 Fans
PC13/PC23 90 125 35 PC13/PC23 Controls 1 Fan*
Cut Out Cut In Differential
Degrees °F
Notes
18 McQuay IM 893-1
Condenser Fan Arrangement
11
12
11
13
23
12
22
21
24
14
11
12
21
22
11
12
21
22
11
12
21
22
11
12
21
22
23
13
11
13
23
12
22
21
Introduction
Table 5 below shows the condenser fan numbering
conventions and locations for each unit size.
Table 5: Condenser Fan Arrangement
Unit size Refrigerant circuit Arrangement Unit size Refrigerant circuit Arrangement
1
015D -
025D
2
1
020D -
042D
2
1
045D
2
1
075D -
090D
2
1
100D
2
1
110 D
2
050D -
060D
062D
070D -
080D
1
120D
2
1
125D
2
1
140D
2
1
2
1
2
1
2
McQuay IM 893-1 19
Mechanical Installation
*Condenser coil replacement is simplified
if the following temporary access clearance
can be arranged:
015D - 025D 61"
030D - 062D 83"
070D - 100D 106"
110D - 140D 38"
*
Mechanical Installation
The installation of this equipment shall be in accordance with
the regulations of authorities having jurisdiction and all
applicable codes. It is the responsibility of the installer to
determine and follow the applicable codes.
Note: Low head pressure may lead to poor, erratic refrigerant
feed control at the thermostatic expansion valve. The
units have automatic control of the condenser fans
which should provide adequate head pressure control
down to 50°F (10°C) provided the unit is not exposed to
windy conditions. The system designer is responsible
for assuring the condensing section is not exposed to
excessive wind or air recirculation.
CAUTION
Sharp edges on sheet metal and fasteners can cause
personal injury.
This equipment must be installed, operated, and serviced
only by an experienced installation company and fully
trained personnel.
Figure 20: Service Clearances
Receiving Inspection
When the equipment is received, all items should be carefully
checked against the bill of lading to be sure all crates and
cartons have been received. If the unit has become dirty
during shipment (winter road chemicals are of particular
concern), clean it when received.
All units should be carefully inspected for damage when
received. Report all shipping damage to the carrier and file a
claim. In most cases, equipment is shipped F.O.B. factory and
claims for freight damage should be filed by the consignee.
Before unloading the unit, check the unit nameplate to make
sure the voltage complies with the power supply available.
Unit Clearances
Service Clearance
Allow service clearance approximately as indicated in
Figure 20. Also, McQuay recommends providing a roof
walkway to the rooftop unit as well as along at least the two
sides of the unit that provide access to most controls and
serviceable components.
20 McQuay IM 893-1
Ventilation Clearance
24" (610 mm)
maximum
96" (2438 mm)
minimum,
top of unit to
permanent
overhead
obstruction
24" (610 mm)
maximum
Overhead
canopy
9" (229 mm)
minimum to flue box,
typical all sides
Flue box
Mechanical Installation
Below are minimum ventilation clearance recommendations.
The system designer must consider each application and
provide adequate ventilation. If this is not done, the unit will
not perform properly.
Unit(s) surrounded by a screen or a fence:
The bottom of the screen or fence should be at least 1 ft.
1
(305 mm) above the roof surface.
2 The distance between the unit and a screen or fence should
be as described in “Service Clearance” on page 20. See also
Figure 20 on page 20.
3 The distance between any two units within a screen or
fence should be at least 120" (3048 mm).
Unit(s) surrounded by solid walls:
1 If there are walls on one or two adjacent sides of the unit,
the walls may be any height. If there are walls on more than
two adjacent sides of the unit, the walls should not be
higher than the unit.
2 The distance between the unit and the wall should be at
least 96" (2438 mm) on all sides of the unit.
3 The distance between any two units within the walls should
be at least 120" (3048 mm).
Do not locate outside air intakes near exhaust vents or other
sources of contaminated air.
If the unit is installed where windy conditions are common,
install wind screens around the unit, maintaining the
clearances specified (see Figure 21). This is particularly
important to prevent blowing snow from entering outside air
intake and to maintain adequate head pressure control when
mechanical cooling is required at low outdoor air
temperatures.
Overhead Clearance
1 Unit(s) surrounded by screens or solid walls must have no
overhead obstructions over any part of the unit.
2 The area above the condenser must be unobstructed in all
installations to allow vertical air discharge.
3 The following restrictions must be observed for overhead
obstructions above the air handler section (see Figure 21):
a There must be no overhead obstructions above the
furnace flue, or within 9" (229 mm) of the flue box.
b Overhead obstructions must be no less than 96"
(2438 mm) above the top of the unit.
c There must be no overhead obstructions in the areas
above the outside air and exhaust dampers that are
farther than 24" (610 mm) from the side of the unit.
Figure 21: Overhead Clearance
McQuay IM 893-1 21
Mechanical Installation
See DETAIL A
(INSIDE)
015D - 025D = 52.00
030D - 068D = 64.00
070D - 105D = 83.00
110D - 140D = 120.00
(INSIDE)
Roof Curb Assembly and Installation
Locate the roof curb and unit on a portion of the roof that can
support the weight of the unit. The unit must be supported to
prevent bending or twisting of the machine.
If building construction allows sound and vibration into the
occupied space, locate the unit over a non-critical area. It is
the responsibility of the system designer to make adequate
provisions for noise and vibration in the occupied space.
WARNING
Mold can cause personal injury. Some materials such as
gypsum wall board can promote mold growth when damp.
Such materials must be protected from moisture that can enter
units during maintenance or normal operation.
Install the curb and unit level to allow the condensate drain to
flow properly and allow service access doors to open and close
without binding.
Integral supply and return air duct flanges are provided with
the RPS/RFS roof curb, allowing connection of duct work to
the curb before the unit is set. The gasketed top surface of the
duct flanges seals against the unit when it is set on the curb.
Figure 22: RCS Roof Curb Assembly
These flanges must not support the total weight of the duct
work. See “Installing Ductwork” on page 40 for details on duct
connections. It is critical that the condensate drain side of the
unit be no higher than the opposite side.
Assembly of a typical RPS/RDT roof curb is shown in
Figure 23 on page 23. Parts A through K are common to all
units having bottom supply and return openings. Depending on
the unit length, Parts L and M may be included with the roof
curb kit to create the correct overall curb length. Figure 22
shows the assembly of the RCS roof curb.
RCS Assembly instructions (Figure 22)
1 Set curbing parts (A) in place making sure that the
orientation complies with the assembly instructions. Check
alignment of all mating bolt holes.
2 Bolt curbing parts together using fasteners provided.
3 Curb must be level from side to side and over its length.
4 Weld curbing in place. Caulk all seams watertight and
insulate between channels.
5 Flash curbing into roof as shown in Detail C.
RPS/RDT Assembly instructions (Figure 23 on
page 23)
1 Set curbing parts A through K per dimensions shown over
2 If applicable, set other curbing parts (D, L, M, etc.) in place
3 Bolt curbing parts together using fasteners provided.
4 Square entire curbing assembly and securely tighten all
22 McQuay IM 893-1
roof opening or on a level surface. Note location of return
and supply air openings.
making sure that the orientation complies with the
assembly instructions. Check alignment of all mating bolt
holes. See Detail A.
Tighten all bolts finger tight.
bolts.
5 Position curb assembly over roof openings. Curb must be
level from side to side and over its length. Check that top
surface of the curb is flat with no bowing or sagging.
6 Weld curbing in place. Caulk all seams watertight. Remove
backing from 0.25" (6 mm) thick × 1.50" (38 mm) wide
gasketing and apply to surfaces shown by cross-hatching.
7 Flash curbing into roof as shown in Detail B.
8 Parts E and F are not required on units with no return shaft
within the curb perimeter.
9 Parts G and H are not required on units with no supply shaft
within the curb perimeter.
10 Be sure that electrical connections are coordinated (see
Figure 24).
Figure 23: RPS/RFS Roof Curb Assembly
Mechanical Installation
Table 6: RPS/RFS Roof Curb Assembly Dimensions
Unit size Return Fan
015D – 042D 2 x 15" FC
30" AF
40" AF
None
045D – 075D All units 38.0 965 87.0 2210 030D 56.2 1427 030D 20 508
080D – 140D All units 62.0 1575 87.0 2210 035D – 040D 57.3 1455 035D – 040D 20 508
Note: These dimensions do not apply to units with energy recovery wheels.
X Y
in mm in mm in mm in mm
2083
82
610
24
1930
76
762
30
36|
24
914
610
78
82
1981
2083
Unit size
015D – 025D 53.6 1361 015D – 025D 20 508
045D – 068D 61.0 1594 045D – 075D 28.0 711
070D – 105D 74.0 1880 080D – 090D 38.0 965
110D – 140D 99.0 2514 100D – 140D 46.0 1168
Z
Unit size
W
McQuay IM 893-1 23
Mechanical Installation
Unit length minus 6.4
12.1
See Detail A
Detail A
3.4
5.1
0.9 Dia.
K.O.
3.0 Dia.
K.O.
4.6
4.8
2.0
2.1
4.3
3.1
9.7
76.0
7.5
20.0
1.5
6.8
OPNG
B
2Typ
A
A
D
C
D
4Typ
A
SA
OPNG
RPS only
RA
Figure 24: Typical Power Wire Entrance, Curb View (RPS/RFS 045D to 140D shown, See Project Certified Drawings)
24 McQuay IM 893-1
Post and Rail Mounting
* Beam can extend beneath unit no more than 5” to allow adequate space
for duct connections and electrical entry.
Unit has either four or six lifting points (four-point shown below).
Rigging cables must be at least as long as distance “A”
Spreader bars
required
Lift only as indicated
Caution: Lifting points may not
be symmetrical to center of
gravity of unit. Balast or unequal
cable lengths may be required.
A
Mechanical Installation
When mounting by post and rail, run the structural support the
full length of the unit. Locate the structural member at the base
of the unit as shown in Figure 25, assuring the I-beam is well
supported by the structural member.
CAUTION
The unit must be level side to side
and over the entire length.
Equipment damage can result if the unit is not level.
If resilient material is placed between the unit and the rail,
insert a heavy steel plate between the unit and the resilient
material to distribute the load. Seal cabinet penetrations
(electrical, piping, etc.) properly to protect against moisture
and weather.
Figure 25: Post and Rail Mounting
99"
MAX.
1 Support the unit well along the length of the base rail.
2 Level the unit (no twists or uneven ground surface).
3 Provide proper drainage around the unit to prevent flooding
of the equipment.
4 Provide adequate protection from vandalism, mechanical
contact, etc.
5 Securely close the doors.
6 If there are isolation dampers, make sure they are properly
installed and fully closed to prevent the entry of animals
and debris through the supply and return air openings.
7 Cover the supply and return air openings on units without
isolation dampers.
Figure 26 shows an example of the rigging instruction label
shipped with each unit.
WARNING
Use all lifting points. Improper lifting can cause severe personal
injury and property damage.
Figure 26: Rigging and Handling Instruction Label
Rigging and Handling
Lifting brackets with 2" (51 mm) diameter holes are provided
on the sides of the unit.
Use spreader bars, 96" to 100" (2438 to 2540 mm) wide to
prevent damage to the unit cabinet. Avoid twisting or uneven
lifting of the unit. The cable length from the bracket to the
hook should always be longer than the distance between the
outer lifting points.
If the unit is stored at the construction site for an intermediate
period, take these additional precautions:
McQuay IM 893-1 25
CAUTION
Lifting points may not be symmetrical to the center of gravity of
the unit. Ballast or unequal cable lengths may be required.
Mechanical Installation
4 Lifting Points
A
Lifting Points
Refer to Figure Note: and Figure 28 and the following
calculations to determine whether a four or six point lift is
required.
X = distance from the entering air end of the unit (or shipping
section) to the first lifting lug in the direction of air flow.
For all unit or shipping sections with outdoor air/return air
options, X = 48"
For shippings sections without outdoor air/return air
options, X= 0
Y = distance from condenser or leaving air end of unit to the
last lifting lug.
For all units or shipping sections with condensers, Y = 25.6
(sizes 30-40), Y = 13.9 (sizes 15-25), Y = 36.5 (sizes 50-68),
Y = 30.0 (sizes 70-105), or Y = 38.0 (sizes 110-140).
For all units or shipping sections without condensers, Y = 0.
Installation
Z = total base rail length of the units.
Note: Z excludes hoods and overhung parts extending past
base rails of the unit.
Figure 27: RPS/RDT Lifting Points
A = Z - X - Y
If A < 288", 4-point lift is sufficient
If A > 288", 6-point lift is required
B = distance from first lifting lug to middle lifting lug on units
with 6-point lift.
B = A / 2 +/- 48"
Note: Middle lifting lug may be installed on either side of the
midpoint to avoid interference with condensate drains.
RDT 050D–140D: B Min. = 72” (1829 mm)
RPS 080D–105D: B Min: = 96” (2348 mm)
RPS 110D–140D: B Min: = 120” (3048 mm)
Figure 28: RCS or Condenser Factory Split at Condenser
B
015D – 042D: B (min.) = 82" (2362 mm)
045D – 068D: B (min.) = 59" (1448 mm)
070 B (min.) = 82" (2362 mm)
D – 105D:
110D – 140D: B (min.) = 115" (2870 cm)
26 McQuay IM 893-1
Mechanical Installation
Z
4 Lifting Points
Z
B
045D–068D: B Min. = 72 (1829 mm)
070D–105D: B Min. = 96 (2438 mm)
110D–140D: B Min. = 120 (3048 mm)
Figure 29: RPS Factory Split at Supply Fan Section
refrigerant piping intact so field evacuation and charging is not
required. Detailed instructions are on pages 27 to 29.
A single nameplate is attached to the air handler section and
power is fed to both sections through the main control box, as
in a non-split RPS/RDT unit.
Field reassembly of an RPS/RDT unit that has shipped split at
the fan takes place in three phases: (1) setting the sections
(2) mechanically recoupling the cabinet, and (3) reconnecting
power and control wiring.
Phase I. Set sections (Figure 30)
1 Remove top cap and save for Step 3.
2 Remove screws on fan panel, leaving retainer clips in place
to secure bulkhead. Save screws for Phase II, Step5.
3 Remove plywood and retaining angles from unit and
discard.
4 Carefully lower both sections of unit (fan end and
discharge end) into place, making sure the roof curb
engages the recesses in the unit base.
Reassembly of Split Units
Although RoofPak units typically ship from the factory as
complete units, they may be split at the factory in one of two
possible configurations; see (1) “RPS Factory Split at Fan”
below and (2) “RFS/RCS Permanent Split Systems” on page
30.
RPS Factory Split at Fan
The RPS unit is factory split at the fan section and ships as two
pieces, split at the supply fan bulkhead, to recouple together on
the roof. Like the RPS/RDT unit factory split at the condenser,
this configuration is ordered if shipping length or weight
limitation prevents a packaged RPS/RDT from being ordered.
Splitting at the fan has the advantage of leaving all factory
McQuay IM 893-1 27
Mechanical Installation
Remove top cap and
save for reassembly.
Remove plywood and retaining
angles from unit and discard.
Discharge end of unit
Fan end of unit
Remove screws on fan panel,
leaving retainer clips in place.
Save screws for reassembly.
Reinstall top cap
saved in step 1
Caulk ends
of splice cap
See detail
Splice cover,
provided
#10 screws,
provided
Nut clip-on,
provided
Caulk
vertical
seam
Install screws
(.25 to 20 × .75)
saved from step 1
Figure 30: Set Sections - Steps 1-4, RPS Factory Split at Supply Fan
Phase II. Reassemble cabinet (Figure 31)
1
Reinstall top cap removed in Phase I, Step 1.
2 Caulk (watertight) ends of splice cap.
3 Caulk (watertight) vertical seam.
Figure 31: Reassemble Cabinet
4 Install #10 screws (provided).
5 Install screws (.25–20 × .75) removed in Phase I, Step 2
6 Install splice cover (provided).
28 McQuay IM 893-1
Phase III. Reconnect Power and Control Wiring
If applicable, install as shown
with provided fasteners.
After routing wires,
install inner raceway
cover (see step 6).
3.72 ref.
(94 mm)
Capped
refrigerant
lines
Mechanical Installation
The DX coil/condenser section contains power and control
harnesses that have their excess length in the blank or heat
section, which normally is immediately downstream of the fan.
Once the sections are physically reconnected, the ends of the
power harness are fed back through the unit base into the
junction box, per the unit’s electrical schematics.
CAUTION
Connect the power block correctly and maintain proper
phasing. Improper installation can cause severe equipment
damage.
1 Make electrical connections and reinstall inner raceway
cover as shown in Figure 32.
Figure 32: Electrical Connections/Cover Installation
When power wire reconnection is complete, reinstall the
2
inner raceway cover in the blank or heat section. Figure 32
shows a typical installation of the raceway cover.
3 Run the control harnesses by removing the external
raceway covers on either side of the unit split.
4 Remove the excess harness length from the external
raceway on the DX side of the split; then route along the
raceway through the bushed hole in the fan section and into
the junction box where control wiring terminal blocks are
provided for reconnection.
5 Make all electrical connections per the unit’s electrical
schematics.
6 Reinstall the external raceway covers after routing of the
control wires is complete.
7 Draw through cooling coils only. Reconnect refrigerant
piping. These refrigerant circuits for these units are shipped
with a holding charge only. Figure 33 illustrates what the
installer sees at the shipping split
a To bridge the gap and connect the piping, remove the
refrigerant piping caps and add fittings and copper
tubing, as required.
b Evacuate and charge the unit. See page 32 for further
details.
Figure 33: Refrigerant Lines
McQuay IM 893-1 29
Mechanical Installation
RFS/RCS Permanent Split Systems
The RFS air handler section and RCS condenser section ship
as two separate units. This configuration is ordered when the
condenser is intended to remain separated by a short distance
from the air handler because of space or structural constraints.
Small traps should be provided at the base of each major
vertical gas riser to assist in the collection of oil. If vertical
risers exceed more than 25 feet, install a small trap at the
midpoint and at a maximum of 20 foot intervals.
On all units, refrigerant piping is terminated near the exterior
of the cabinet for convenient field piping between the RCS and
RFS units, and all necessary refrigeration components are
provided (except the field-installed hot gas bypass valve).
Detailed instructions are on pages 32 to 35.
The hot gas bypass valve should be located at the high point of
the piping, so that refrigerant does not accumulate at the valve
when it is shut, and also should be located as close to the RCS
as possible. Minimize pipe bends (especially those that
accumulate refrigerant) as much as possible. Connect the
pressure sensing tap to the suction line.
Piping Recommendations
All field piping, wiring, and procedures must be performed in
accordance with ASHRAE, EPA, and industry standards.
Proper refrigerant piping can make the difference between a
reliable system and an inefficient, problematic system.
The primary concerns related to piping are refrigerant pressure
drop, a solid liquid feed to the expansion valves, continuous oil
return and properly sized refrigerant specialties.
Insulate the suction line to reduce excessive superheat buildup. Insulate the liquid line, where located in areas above
ambient temperature, to prevent loss of subcooling and
consequent liquid flashing.
The recommended source for refrigerant piping techniques and
sizing is the McQuay AG31-011 Refrigerant Piping Design
Guide.
Although conflicting piping recommendations can be found in
different sources, McQuay offers the following
recommendations for these controversial issues.
Use caution in sizing the liquid line in applications where the
evaporator is above the outdoor section. The weight of the
liquid refrigerant in the vertical column will decrease the
pressure at the top of the riser (approximately 0.5 psi per foot
of vertical rise) allowing some of the refrigerant to flash to a
gas. Adequate refrigerant subcooling is needed at the outdoor
section to prevent large volumes of refrigerant gas at the
expansion valve.
The piping systems should always extend above the highest
component in the refrigeration system before dropping down
to make the final refrigerant connections to components. This
practice will hinder the draining of condensed refrigerant to
the lower component when normal shutdown procedures do
not occur (such as a power failure).
Note: Do not run refrigerant lines underground.
1 Use type K or L clean copper tubing. Thoroughly clean or
braze all joints with high temperature solder. Make sure
nitrogen is flowing through the tubes while brazing to
minimize the formation of oxide contaminants.
2 Base piping sizes on temperature/pressure limitations as
recommended in the following paragraphs. Under no
circumstances should pipe size be based strictly upon coil
or condensing unit piping connection size.
3 To determine the minimum tonnage required to carry oil up
suction risers of various sizes, check the vertical suction
risers using Table 7.
4 Size the liquid line for a pressure drop not to exceed the
pressure equivalent of 2°F (1°C), 6 psi (41.4 kPa)
saturated temperature. The filter drier, solenoid, and
sight glass ship loose with each RFS unit.
The use of double risers for vertical gas risers is generally not
required and should be used only as a last resort to maintain
the minimum refrigerant flow to carry oil up the vertical risers.
Slightly downsizing the vertical riser is a preferable option to
providing double risers.
Slope the refrigerant lines 1" per 10 feet of horizontal run in
the direction of refrigerant flow to assist oil return.
Pressure drops in the refrigerant lines should be maintained at
or below the ASHRAE recommendations and line lengths
should be made as short as possible. Exceeding these
Table 7: Minimum Tonnage (R-410A) to Carry Oil Up
Suction Riser at 40°F Saturated Suction
Line size O.D. Minimum tonnage
1 1/8" 2.0
1 3/8" 3.5
1 5/8" 5.4
2 1/8" 11.2
2 5/8" 19.5
*3 1/8" 30.5
* McQuay’s largest suction connection is 2 5/8" and is generally sufficient.
recommendations will decrease performance and could impact
reliability.
30 McQuay IM 893-1
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