McQuay RAH 407C Installation Manual

Installation and Maintenance Manual IM 487-5

RoofPak™ Applied Rooftop Systems Air Handler

RAH 407C - 077C, 12000 to 50000 cfm

RDS 800C - 802C, 4000 to 20000 cfm

Group: Applied Systems

Part Number: IM 487

Date: June 2006

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Gas Burner Nameplate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Hazard Identification Information . . . . . . . . . . . . . . . . . . . . . . . 3

Typical Component Locations . . . . . . . . . . . . . . . . . . . . . . . . . 4

Control Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Controls, Settings, and Functions . . . . . . . . . . . . . . . . . . . . . 12

Mechanical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Unit Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Ventilation Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Overhead Clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

IBC Seismic Compliant Units . . . . . . . . . . . . . . . . . . . . . . . . 20

Roof Curb Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Post and Rail Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Post and Rail Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Rigging and Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Split Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Unit Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Steam Coil Piping (All Units) . . . . . . . . . . . . . . . . . . . . . . . . . 33

Steam Piping Recommendations . . . . . . . . . . . . . . . . . . . . . 33

Steam Trap Recommendations . . . . . . . . . . . . . . . . . . . . . . . 34

Vestibule Assembly Instructions . . . . . . . . . . . . . . . . . . . . . . 38

Damper Assemblies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Cabinet Weather Protection . . . . . . . . . . . . . . . . . . . . . . . . . 45

Installing Ductwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Installing Duct Static Pressure Sensor Taps . . . . . . . . . . . . . 46

Installing Building Static Pressure Sensor Taps . . . . . . . . . . 47

Electrical Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Field Power Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Field Control Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Preparing Unit for Operation . . . . . . . . . . . . . . . . . . . . . 52

Spring Isolated Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Relief Damper Tie-Down . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Adjusting Scroll Dampers . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Adjusting Supply Fan Thrust Restraints . . . . . . . . . . . . . . . . 53

Adjusting Seismic Restraints . . . . . . . . . . . . . . . . . . . . . . . . . 54

Sequences of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Power-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Fan Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Economizer Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Unit Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Enthalpy Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

External Time Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Smoke and Fire Protection . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Smoke Detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Freeze Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Entering Fan Temperature Sensor . . . . . . . . . . . . . . . . . . . . 87

Duct High Pressure Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

MicroTech II™ Remote User Interface (UI) . . . . . . . . . . . . . . 87

Variable Frequency Drive Operation . . . . . . . . . . . . . . . . . . . 89

Convenience Receptacle/Section Lights . . . . . . . . . . . . . . . . 89

DesignFlow™ Outdoor Air Damper Option . . . . . . . . . . . . . . 89

Propeller Exhaust Fan Option . . . . . . . . . . . . . . . . . . . . . . . . 92

Exhaust Fan On/Off Control . . . . . . . . . . . . . . . . . . . . . . . . . . 94

Ultraviolet Lights Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Ultraviolet Light Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Check, Test, and Start Procedures . . . . . . . . . . . . . . . 97

Servicing Control Panel Components . . . . . . . . . . . . . . . . . . 97

Before Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Power Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Fan Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Economizer Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

Heating System Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Air Balancing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Sheave Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Drive Belt Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

Mounting and Adjusting Motor Sheaves . . . . . . . . . . . . . . . 101

Final Control Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Servicing Control Panel Components . . . . . . . . . . . . . . . . . 108

Planned Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Unit Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Gas Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Bearing Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Setscrews . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

Supply Fan Wheel-to-Funnel Alignment . . . . . . . . . . . . . . . 112

Winterizing Water Coils . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

Control Panel Components . . . . . . . . . . . . . . . . . . . . . . . . . 113

Replacement Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . 117

Service and Warranty Procedure . . . . . . . . . . . . . . . . 119

Limited Product Warranty (North America) . . . . . . 120

Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Sole Remedy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Rooftop Equipment Warranty Regist. Form . . . . . 121

Introduction

This manual provides general information about the “C” vintage McQuay RoofPak applied rooftop unit, models RDS and RAH. 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 Bulletin No. IM 684 or IM 685.

The MicroTech II applied rooftop unit controller is available on “C” vintage applied rooftop units. For a detailed description of the MicroTech II components, input/output configurations, field wiring options, requirements, and service procedures, see IM 696-3. For operation and information on using and programming the MicroTech II unit controller, refer to the appropriate operation manual (see Table 1).

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 Table 1).

Table 1: Program specific rooftop unit operation literature

Rooftop unit control configuration

VFDs Vendor IM manuals

Discharge Air Control (VAV or CAV) OM 137-2

Space Comfort Control

(CAV-Zone temperature control)

Operation manual bulletin

number

OM 138-2

Gas Burner Nameplate

On units that include gas heat, the nameplate is located on the lower right corner of the main control box door. It includes the burner model number, minimum/maximum input, maximum temperature rise, and minimum cfm.

Hazard Identification Information

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

RoofPak

Unit Size RDS 800 = 4000 – 16000 CFM RDS 802 = 8000 – 20000 CFM RAH 47 = 12000 – 30000 CFM RAH 77 = 23000 – 50000 CFM

R AH — 047 C S E

Heat medium A = Natural gas E = Electric F = Fuel oil S = Steam W = Hot water Y = None

Cooling coil size S = Standard (low airflow) L = Large (high airflow) Y = None or contractor coil

Design vintage

McQuay IM 487-5 3

Introduction

Typical Component Locations

Figure 2 shows a typical blow-through unit with the locations of the major components. Figure 2 shows a typical draw-through 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 2: Control locations

Supply fan

discharge

plenum

section

Economizer

return air

Heat

section

Filter

section

Control Locations

All controls are optional. If controls are ordered, Figure 2 shows the locations of the various control components mounted throughout the units. See “Control Panel” on page 5 for the locations of control components mounted in control panels. Additional information is included in Table 2 on page 12 and the wiring diagram legend, which is included in “Wiring Diagrams” on page 58. Figure 2 shows the blow-through heat and the blow-through coil sections.

C19, 20

(optional)

RAT

LT11 (optional)

S11, REC11

SD2

(optional)

RAE

(optional)

ACT3

ACT6

PC5

OAE

OAT

VM1

(optional)

FS1

(optional)

DAT

LT10 (optional)

S10, REC10 (optional)

SD1 (optional)

SV1, 2

SV5, 6 (optional)

4 McQuay IM 487-5

Control Panel

Introduction

The unit control panels and their locations are shown in the following figures. These figures show a typical unit

Figure 3: Control panel locations

configuration. Specific unit configurations may differ slightly from these figures depending on the particular unit options.

McQuay IM 487-5 5

Introduction

Figure 4: Typical main control panel, 800C to 802C, 460 volt

Keypad display

Remote

keypad

HS1 S1

Serial conn

See separate

detail, page 14.

GCB1

ERB1

S7S4

Resistor

R58

R20 R26 R27 R28

R48

R46

MMP60 MMP10 MMP20

M60

R30

M10

R24 R25 R28

R60

R45

R69

M20

F1A

F1B

MCB

F1C

TB1

Power supply

DHL

SPS2

EHB1

SPS1

VFD remote

display

DS1

REC1

TB3,

first seven

blocks

TB2,

remaining

blocks

TB7

GND LUG DS1

SPS1,2 fittings

for static

pressure tubing

6 McQuay IM 487-5

Figure 5: Typical main control panel, 047C, 460 volt

Introduction

VFD remote

display

TB2

F1A

F1B

F1C

14.

GFR1

TB7

SPS1,2

fittings for

static pressure

tubing

McQuay IM 487-5 7

Introduction

Figure 6: Typical main control panel, 077C, 460 volt

14.

8 McQuay IM 487-5

Introduction

Figure 7: Typical gas heat panel, 1000 MBH

R22

TD10

R20

R23 R21

LS2

Figure 9: VFD bypass panel, 40 HP, 460 volt)

LS1

Figure 10: Electric heat panel, sizes 800, 802C

FSG

FSG Tim

FB33 FB32 FB31

Figure 8: Typical propeller exhaust panel, 3 fans, 460 volt

M33 M32 M31

FB43 FB42 FB41

M41 M42 M41

SR2

SR3

SR1

TB11

PB3

McQuay IM 487-5 9

Introduction

Figure 11: Electric heat panel, size 047C Figure 12: Electric heat panel, size 077C

FB31FB32FB33

DS3

M42

GLG3

FB31FB32FB33 M31M32M33

FB41FB42FB43

M41M43

H53

TB11

M31M32M33

FB34FB44

M34M44

FB41FB42FB43

M41M42M43

GLG3

H53

TB11

DS3

10 McQuay IM 487-5

Figure 13: Harness plug connector detail

RATS OATSDATS

FP1 OPEN1EPTS

AFD10 AFD20

SV12 SV56

ACT3 OPEN2

OAE PC7PC5

Introduction

HL22 OPEN3

GSHT1 GSHT2

SD1 SD2

DFRH DFLH OPEN4

LT11LT1 0

LT OP1 LT OP2

McQuay IM 487-5 11

Introduction

Controls, Settings, and Functions

Table 2 below lists all of the unit control devices and associated information.

Table 2: Controls, settings, and functions

Symb

DAT

DHL

EFT

FP1, 2

FS1

MCB

OAE

OAT

PC5

PC6

PC7

RAE

RAT

SD1

SD2

SPS1

Description Function

Discharge air temperature sensor

Duct high limit switch

Entering fan air temperature sensor

Evaporator frost protection

Freezestat

Main control board Processes input information

Enthalpy control (electromechanical)

Enthalpy control (electronic)

Outside air temperature sensor

Dirty filter switch Senses filter pressure drop

Airflow proving switch

Return air enthalpy sensor

Return air temperature sensor

Smoke detector, supply air

Smoke detector, return air

Static pressure sensor duct #1

Senses discharge air temperature

Prevents excessive VAV duct pressures; shuts off fan

Senses entering fan air temperature

Senses low refrigerant temperature

Shuts off fans, opens heating valve, and closes outdoor damper if low air temperature at coil is detected

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

Initiates unit shutdown if smoke is detected

Converts static pressure signals to voltage signals

Rese

N/A

Auto

N/A

Auto

N/A

Auto

N/A N/A N/A

Auto

N/A

ManualDischarge air

ManualReturn air

N/A

Location Setting Range Differential Part no.

Discharge air

section

Main control

panel

Inlet of supply

fan

Return bends of evaporative

coil

Heating section

Main control

box

Economizer

section

Economizer

section

First filter

section

Final filter

section

Supply fan

section

Economizer

section

Return air

section

Main control

box

N/A N/A

3.5" w.c

(871.8 Pa)

N/A N/A

Opens at

30°F

Closes at

45°F

38°F (3°C)

or as

required

N/A N/A N/A

“B” or as required

Fully CW

past “D”

(when used

with RAE)

As required

.10" wc (25

Pa)

N/A N/A N/A

N/A N/A

N/A N/A N/A 04925001

N/A

0.05–5.0" wc (12.5–1245.4

Pa)

N/A N/A

35°F–45°F

(2°C–7°C)

A–D

A–D N/A

.05-5" wc

(12.5–1245.4

Pa)

.05-5" wc

(12.5–1245.4

Pa)

.03-1.40" wc

(7.5–348 Pa)

0–5" wc (0–1245.4 Pa) 1–6 V (dc) out

.05" wc

(12.5 Pa),

fixed

12°F (7°C),

fixed

Temperature:

3.5°F (2°C) Humidity:

5% fixed

.05" wc

(12.5 Pa)

.05" wc

(12.5 Pa)

.03" wc

(7.5 Pa),

fixed

N/A

06000470

06549380

06000470

07250190

06583000

06000610

03070670

04926220

06000470

06549380

06001580

04926220

06000470

04954500

12 McQuay IM 487-5

Table 2: Controls, settings, and functions (continued)

Symb

SPS2

Description Function

Converts static pressure Static pressure sensor duct #2

Static pressure sensor: building (space) pressure

System switch

ON-OFF-AUTO switch

signals to voltage signals and

sends them to MicroTech II

controller

Converts static pressure

signals to voltage signals.

Shuts off entire control circuit

(except crankcase heaters)

Used to manually switch unit

Rese

N/A

Introduction

Location Setting Range Differential Part no.

Main control

box

Main control

box

Main control

box

Main control

box

N/A

N/A N/A N/A

0–5" wc (0–1245.4 Pa) 1–6 V (dc) out

-025–0.25" wc

(-62.3–62.3 Pa)

1–5 V (dc) out

N/A

04954500

00135500

McQuay IM 487-5 13

Mechanical Installation

Note – 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.

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.

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.

Figure 14: Service clearances, unit with housed DWDI supply fan

72"

(1829 mm)

All units should be inspected carefully for damage when received. Report all shipping damage to the carrier and file a claim. In most cases, equipment ships 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 an approximate service clearance as indicated in Figure 14. Also, McQuay recommends providing a roof walkway to the rooftop unit as well as along two sides of the unit that provide access to most controls and serviceable components.

72"

(1829 mm)

Roof

Walkway

Note: Sections with heating and/or cooling coils or DWDI supply fan must have noted service clearance on the control box side.

To Roof

Access

Location

(1524 mm)

B C

60"

Varies With Unit Arrangement

Refer to Certified Drawing & Note

Dimension "X" RDS 800-802 = 90" (2286mm) RAH 47-77 = 96" (2438mm)

24"

(635 mm)

Legend: A = Return Air Section B = Filter Section C = Cooling Section D = Cooling/Supply Fan Section E = Heat Section F = Discharge Plenum Section

14 McQuay IM 487-5

Figure 15: Service clearances, unit with SWSI plenum supply fan

72"

(1829 mm)

Mechanical Installation

72"

(1829 mm)

Roof

walkway

Note: Sections with heating and/or cooling coils or DWDI supply fan must have noted service clearance on the control box side.

To roof

access

location

(1524 mm)

B C

60"

Varies with unit arrangement. Refer to Certified Drawing and note below.

96"

(2438 mm)

Ventilation Clearance

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:

1 The bottom of the screen or fence should be at least 1 ft.

(305 mm) above the roof surface.

2 The distance between the unit and a screen or fence should

be as described in Figure 15.

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).

E F

Legend: A = Return air section B = Filter section C = Cooling section D = Cooling/supply fan section E = Heat section F = Discharge plenum section

Dimension "X" RDS 800–802 = 90" (2286mm) RAH 47–77 = 96" (2438mm)

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 16). This is particularly important to prevent blowing snow from entering the 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 following restrictions must be observed for overhead

obstructions above the air handler section (see Figure 16):

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.

McQuay IM 487-5 15

Mechanical Installation

Figure 16: Overhead clearance

24" (610 mm) Maximum

Overhead Canopy

9" (229 mm) Minumum to Flue Box Typical All Sides

2" (51 mm)

Minumum

Top of Unit

to Overhead

Obstruction

Figure 17: Side discharge

Flue Box

24" (610 mm) Maximum

Notice

On units with side discharge, access to plenum-mounted components becomes difficult once ductwork is installed. Installer must provide access in the ductwork for plenum mounted controls

Side Discharge Opening (Access in Ductwork Must be Removed)

16 McQuay IM 487-5

Mechanical Installation

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 RAH 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. These flanges must not support the total weight of the duct work. Assembly of a typical RAH roof curb is shown in Figure 18 on page 18. Parts A through H are common to all units having bottom 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.

Assembly instructions

1 Set curbing parts A through H per dimensions shown over

roof opening or on a level surface (see Figure 18 on page 18). Note location of return and supply air openings.

2 If applicable, set other curbing parts (D, L, M, etc.) in place

making sure that the orientation complies with the assembly instructions (see Detail A). Check alignment of all mating bolt holes.

3 Bolt curbing parts together using fasteners provided.

Tighten all bolts finger tight.

4 Square entire curbing assembly and securely tighten all

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 26).

McQuay IM 487-5 17

Mechanical Installation

Figure 18: RAH roof curb assembly instructions

Detail A

Equal Length Side Supports

Using remaining side supports in this area, align lengths on opposite sides of assembly and install a cross support "D" at each side.

3.50"

(90 mm)

8.75"

(222 mm)

81.00"

(2057 mm)

Inside

7.50"

(191 mm)

2.00"

(51 mm)

"Y"

Inside

Supply

Air

"X"

Inside

(222mm)

3.50"

(90mm)

8.75"

87.00"

(2210 mm)

Inside

90.00"

(2286 mm)

Figure 19: Roofing detail “B”

Curb gasketing

Return

Unit base

2 × 4 nailer strip

70.75"

Air

See Detail "A"

(1797 mm)

Dimensions

94.75"

(2407 mm)

RAH unit

047C 077C with flat cooling coil and /or 44" SWSI plenum supply fan 077C with staggered or no cooling coil, and/or 49" SWSI plenum supply fan

X Y

in mm in mm

38 965 28 711

157

38 965

46 1168

(not furnished)Counterflashing

Flashing (not furnished)

Rigid insulation

(not furnished)

Cant strip (not furnished)

Roffing material

(not furnished)

Galvanized

curb

Main unit

curb

18 McQuay IM 487-5

Figure 20: RDS roof curb assembly instructions

20.00"

(508 mm)

Inside

6.80"

(173 mm)

Supply

Air

Mechanical Installation

1.50"

(38 mm)

76.00" (1930 mm) Inside

7.50"

(191 mm)

2.00"

(5.1 mm)

"X"

Inside

"YY"

"XX"

"Y"

Inside

85.00"

(2159 mm)

Return

Air

Table 3: RDS roof curb assembly instructions

Unit size Fan

None 24.0 610 82.0 2083 6.8 173 1.5 38

800–802C

(2) 15” FC 24.0 610 82.0 2083 6.8 173 1.5 38 (2) 15" FC 24.0 610 82.0 2083 6.8 173 1.5 38

30" AF 30.0 762 76.0 1930 6.8 173 4.5 114 30" AF 30.0 762 76.0 1930 6.8 173 4.5 114 40" AF 36.0 914 78.0 1981 14.8 376 3.5 89 40" AF 36.0 914 78.0 1981 14.8 376 3.5 89

X Y XX YY

in mm in mm in mm in mm in mm in mm in mm in mm

38.80"

See Detail "A"

62.80"

(1594 mm)

Unit size

Return

fan

X Y XX YY

(984 mm)

None 24.0 610 82.0 2083 6.8 173 1.5 38

800–802C

McQuay IM 487-5 19

Mechanical Installation

IBC Seismic Compliant Units

It is important to follow these installation instructions for all IBC Seismic compliant McQuay Rooftop units.

IBC Seismic compliant McQuay Rooftop units can be mounted to either a roof curb or a post and rail setup. If using a roof curb, it must be specifically designed for seismic restraint and be IBC seismic compliant (spring isolated or non-isolated type seismic roof curbs are available). Typical construction of a seismic rated roof curb is from structural steel framing and contains seismic hold down brackets for attachment of the rooftop unit (see Figure 21). Post and rail arrangements rated for seismic applications are also available (spring isolated or non-isolated).

IMPORTANT: An acceptable IBC seismic installation provides a direct positive attachment to both the building structure and the roof mounted equipment.

Refer to the roof curb manufacturer’s submittal drawings for actual roof curb assembly, attachment details and rigging instructions for both roof curb and post and rail arrangements.

Figure 21: Typical seismic roof curb (spring isolated)

Roof Curb Arrangement

1 Set the rooftop unit on the roof curb (McQuay Rooftop

units are designed to overhang from the roof curb).

2 Adjust the seismic hold down brackets so they come into

contact with the unit base per Figures 22 and 23 on page

21.

a The seismic hold down brackets should be adjustable

and accommodate the overhang of the rooftop unit.

b If the hold down bracket cannot reach the unit base, use

a shim spacer. See Figure 23 on page 21.

3 Weld each seismic hold down bracket (and shim spacer, if

required) to the unit base as shown in the acceptable weld zone detail in Figure 22 on page 21.

CAUTION

When welding unit to the curb, do not damage wiring (control panel side). Weld ONLY in the specified zone in the acceptable weld zone (see Figure 22 on page 21). Welding must comply with weld fillet size, etc. as indicated in Figure 22 on page 21.

Note – High temperature insulation is installed at the factory to

allow for field welding along the lower front edge region of the unit base.

Duct opening

Seismic hold down brackets

Structural steel frame

Seismic hold down brackets

Spring isolator

20 McQuay IM 487-5

Figure 22: Welding of hold down brackets—unit base, cross-sectional view

Unit power wiring (by factory)

Unit base

.25

Field attachment

Mechanical Installation

Unit control wiring (by factory)

weld

Weld zone

.50"

Acceptable weld zone

Figure 23: Shim spacers on hold down brackets

Shim

spacer

It may be necessary for the contractor to field fabricate spacers or new seismic hold-downs for rooftop units having larger overhang dimensions.

Unit power wiring

(by factory)

Unit base

High temp Insulation

Seismic hold down bracket

Unit control wiring (by factory)

Roof curb

Seismic hold down bracket

Roof curb

McQuay IM 487-5 21

Mechanical Installation

Post and Rail Arrangement

1 Set the rooftop unit on the rails. The rails should run

lengthwise and support the entire unit base.

2 Weld both sides of the unit directly to each rail as shown in

Figures 24 and 25 on page 22. required is dependent on the length of the unit.

a Make the fillet welds 2 inches long, spaced 48 inches

apart on centers.

b Place the end welds 6 to 12 inches from the unit edge.

Figure 24: Welding of unit to rail—unit base, cross-sectional view

The total number of welds

Note – High temperature insulation is installed at the factory to

CAUTION

When welding unit to the curb, do not damage wiring (control panel side). Weld ONLY in the specified zone in the acceptable weld zone (see Figure 24 on page 22). Welding must comply with weld fillet size, etc. as indicated in Figure 24 on page 22.

allow for field welding along the lower front edge region of the unit base.

Unit base

.25

Weld zone

2–48

.50"

Acceptable weld zone

Figure 25: Weld locations for rail arrangement

6–12"

Unit power wiring

(by factory)

Unit base

Rail

Field attachment

weld

High temp insulation

Unit control wiring

(by factory)

Rail

Rooftop unit

.25

2–48

Weld every 48"

Rails

6–12"

22 McQuay IM 487-5

Mechanical Installation

Figure 26: Typical power wire entrance, curb view (RDS 800–802 shown; for exact values, refer to submittal)

Detail A

20.0

OPNG

6.0

6.8

1.5

76.0

7.5

6.0

3.0 Dia. K.O.

RPS only

97.0

8.0

2Typ 4Typ

K.O.

OPNG

See Detail A

Unit length minus 6.4

12.1

5.1

3.4

0.9 Dia.

2.0

4.6

4.8

9.7

2.1

3.1

4.3

McQuay IM 487-5 23

Mechanical Installation

Post and Rail Mounting

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 27, 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 27: Post and rail mounting

99" RAH

(2515 mm)

94" RDS

5" *

(127mm)

(2388 mm)

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 28 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 28: 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, follow these additional precautions:

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

Caution: Lifting points may not be symmetrical to center of gravity of unit. Balast or unequal

Lift only as indicated

cable lengths may be required.

CAUTION

Lifting points may not be symmetrical to the center of gravity of the unit. Ballast or unequal cable lengths may be required.

24 McQuay IM 487-5

Mechanical Installation

Lifting Points

To determine the required lifting cable lengths and whether four-point or six-point lifting is required, use Tables 4 and 5 and Figure 29.

Referring to Figure 29, note that dimension A is the distance between the outer lifting points. The four outer rigging cables must be equal to or longer than dimension A. Dimension B shows the minimum distance between the outer and the inner lifting points for six-point lifting. Use this to roughly determine the required length of the middle cables for sixpoint lifting. Determine dimension A by subtracting dimensions X and Y from dimension Z (e.g., A = Z – X – Y).

• Where:

• Z = Total unit length in inches

(refer to certified drawings for this dimension).

• X = Outdoor/return air section length (refer to Figure 29 and Table 5 for this dimension).

• If A ≤ 288" (7315 mm), 4-point lifting is sufficient.

• If A > 288" (7315 mm), 6-point lifting is required.

Table 4: RAH X dimension (see Figure 29) Economizer section

Type of economizer

section

100% OA 0 0

Plenum 48” (1219 mm) 72” (1829 mm)

0–30% OA 48” (1219 mm) 72” (1829 mm)

0–100% economizer 72” (1829 mm) 96” (2438 mm)

0–100% economizer with return fan 72” (1829 mm) 96” (2438 mm)

047C 077C

Figure 29: Unit type RAH lifting points

4 Lifting Points

6 Lifting Points

Table 5: RDS X dimension (see Figure 29) Outdoor/return air section

Outdoor/return air section 800C 802C

100% OA 0 0

Plenum 40” (1016 mm) 52" (1321 mm)

0–30% OA 40” (1016 mm) 52" (1321 mm)

0–100% economizer 40” (1016 mm) 52" (1321 mm) 0–100% economizer with 15" return fan 62" (1575 mm) — 0–100% economizer with 30" return fan 52" (1321 mm) 52" (1321 mm) 0–100% economizer with 40" return fan — 80" (2032 mm)

RDS 800: B Min. = 62" (1515 mm) RDS 802: B Min. = 84" (2134 mm) RAH 47: B Min. = 96" (2438 mm) RAH 77: B Min. = 120" (3048 mm)

McQuay IM 487-5 25

Mechanical Installation

Split Units

Although units typically ship from the factory as complete units, they can be factory split at the supply fan bulkhead and connected later on the roof. This configuration is ordered if the shipping length or a weight limitation prevents ordering a packaged unit.

A single nameplate is attached to the air handler section and power is supplied to both sections through the optional main control box as in a packaged unit.

RAH Factory Split at Fan

Field reassembly of an RAH unit that shipped split at the fan takes place in three phases: (1) setting the sections,

Figure 30: Set sections

Remove plywood and retaining

Remove top cap and save for reassembly.

angles from unit and discard.

Discharge end of unit

(2) mechanically recoupling the cabinet, and (3) reconnecting power and control wiring.

Phase I. Set sections

Remove top cap and save for Phase II, Step 1.

2 Remove screws on fan panel, leaving retainer clips in place

to secure bulkhead. Save screws for Phase II, Step 5.

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.

Fan end of unit

26 McQuay IM 487-5

Remove screws on fan panel, leaving retainer clips in place. Save screws for reassembly.

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.

4 Install #10 screws (provided).

5 Install screws (.25–20 ×.75) removed in Phase I, Step 2.

6 Install splice cover (provided).

Figure 31: Reassemble cabinet

Mechanical Installation

Reinstall top cap saved in step 1

Caulk ends of splice cap

Splice cover, provided

See detail

Caulk vertical seam

Install screws (.25 to 20 × .75) saved from step 1

#10 screws, provided

Nut clip-on, provided

McQuay IM 487-5 27

Mechanical Installation

Phase III. Reconnect power and control wiring

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 and raceway cover installation

If applicable, install as shown with provided fasteners.

After routing wires, install inner raceway cover (see step 6).

3.72 ref. (94 mm)

Field Refrigerant Piping and Charging of DX Coils

Units that ship from the factory with DX coils installed do not include refrigerant piping or refrigerant controls. The coil assembly is ready for field connections at the distributors and at the suction headers. Piping kits that provide the necessary liquid and hot gas piping and control components are available for field installation. Field-installed refrigerant piping may exit the unit cabinet at one of the following locations:

• Through the floor of the unit.

• Through the discharge and bulkhead of the unit.

• Through a cabinet door near the DX coil that is not required

for service areas.

CAUTION

For any of the above cabinet penetrations, tightly seal the hole to prevent water or air leakage.

In preparing for field piping, remove the plastic plugs on the distributors and unsweat the copper caps at the suction header connections.

Follow piping design, sizing, and installation information presented in ASHRAE handbooks in the design and installation of interconnecting piping. The DX coil and condensing unit are intended to be set at the same elevation, as close as possible to each other to minimize refrigerant pressure drop. Design piping to prevent liquid refrigerant carryover to the compressor and to provide a continuous return of

compressor oil from the system.

2 When power wire reconnection is complete, reinstall the

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 downstream 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.

CAUTION

The pounds of refrigerant in the system may exceed the capacity of the condenser, depending on the amount of refrigerant in the liquid lines between the DX coil and the condensing unit. Refer to condenser manufacturer for information about refrigerant capacity. Suitable means of containing the refrigerant is required.

CAUTION

To prevent liquid return and damage to the compressor on systems with optional hot gas bypass, it is important to locate the bypass solenoid valve at the condensing unit and not at the DX coil.

28 McQuay IM 487-5

Mechanical Installation

Piping Recommendations

7 Use type K or L clean copper tubing. Thoroughly clean or

braze all joints with high temperature solder.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.

8 Do not exceed suction line piping pressure drop equivalent

to 2°F (1°C), 3 psi (20.7 kPa) per 100 feet (30.5 m) of equivalent pipe length. After the suction line size is determined, check the vertical suction risers to verify that oil will be carried up the riser and back to the compressor. Pitch the suction line(s) in the direction of refrigerant flow and make sure they are adequately supported. Lines should be free draining and fully insulated between the evaporator and the compressor. Install a trap on the vertical riser to the compressor.

9 To determine the minimum tonnage required to carry oil up

suction risers of various sizes, check the vertical suction risers using Table 6. Insulate suction lines inside the unit

cabinet to prevent condensation.

Table 6: Minimum tonnage (R-22) to carry oil up suction riser at 40°F saturated suction

Line size O.D. Minimum tonnage

1 1/8" 1.5 1 3/8" 2.5 1 5/8" 3.8 2 1/8" 7.6 2 5/8" 13.10 3 1/8" 20.4 3 5/8" 29.7 4 1/8" 41.3

10 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.

Leak Testing

bring the pressure to a maximum of 125 psig. The unit should then be leak tested with halide or electronic leak detector. After making any necessary repair, the system should be

evacuated as described in the following paragraphs.

WARNING

Do not use oxygen or air to build up pressure. Explosion hazard can cause severe personal injury or death.

Evacuation

After determining the unit is tight and there are no refrigerant leaks, evacuate the system. Use a vacuum pump with a pumping capacity of approximately 3 cu.ft./min. and the ability to reduce the vacuum in the unit to at least 1 mm (1000 microns).

1 Connect a mercury manometer or an electronic or other

type of micron gauge to the unit at a point remote from the vacuum pump. For readings below 1 millimeter, use an electronic or other micron gauge.

2 Use the triple evacuation method, which is particularly

helpful if the vacuum pump is unable to obtain the desired 1 mm of vacuum. The system is first evacuated to approximately 29" (740 mm) of mercury. Then add enough refrigerant vapor to the system to bring the pressure up to 0 pounds (0 microns).

3 Evacuate the system again to 29" (740 mm) of vacuum.

Repeat his procedure three times. This method is most effective by holding system pressure at 0 pounds (0 microns) for a minimum of 1 hour between evacuations. The first pulldown removes about 90% of the noncondensables; the second removes about 90% of that remaining from the first pulldown. After the third pulldown, only 1/10 of 1% of noncondensables remains.

Table 7 on page 30 shows the relationship between pressure, microns, atmospheres, and the boiling point of water.

In the case of loss of the nitrogen holding charge, the unit should be checked for leaks prior to charging the complete system. If the full charge was lost, leak testing can be done by charging the refrigerant into the unit to build the pressure to approximately 10 psig and adding sufficient dry nitrogen to

McQuay IM 487-5 29

Before replacing refrigerant sensors or protective devices, see “Refrigerant Charge” on page 31 for an important warning to prevent an abrupt loss of the entire charge.

CAUTION

Mechanical Installation

Table 7: Pressure-vacuum equivalents

Absolute pressure above zero Vacuum below 1 atmosphere

Microns PSIA Mercury (mm) Mercury (in)

0 0 760.00 29.921 — —

50 0.001 759.95 29,920 1/15,200 –50

100 0.002 759.90 29.920 1/7,600 –40

150 0.003 759.85 29.920 1/5,100 –33

200 0.004 759.80 29.910 1/3,800 –28

300 0.006 759.70 29.910 1/2,500 –21

500 0.009 759.50 29.900 1/1,520 –12

1,000 0.019 759.00 29.880 1/760 1

2000 0.039 758.00 29.840 1/380 15

4,000 0.078 756.00 29.760 1/189 29

6000 0.117 754.00 29.690 1/127 39

8,000 0.156 752.00 29.600 1/95 46

10,000 0.193 750.00 29.530 1/76 52

15,000 0.290 745.00 29.330 1/50 63

20,000 0.387 740.00 29.130 1/38 72

30,000 0.580 730.00 28.740 1/25 84

50,000 0.967 710.00 27.950 1/15 101

100,000 1.930 660.00 25.980 2/15 125

200,000 3.870 560.00 22.050 1/4 152

500,000 9.670 260.00 10.240 2/3 192

760,000 14.697 0 0 1 atmosphere 212

Approximate fraction

of 1 atmosphere

H2O boiling point at each

pressure (

Charging the System

Units are leak tested at the factory and shipped with a nitrogen holding charge. If the holding charge has been lost due to shipping damage, charge the system with enough refrigerant to raise the unit pressure to 30 psig after first repairing the leaks and evacuating the system.

1 After all refrigerant piping is complete and the system is

evacuated, it can be charged as described in the paragraphs following. Connect the refrigerant drum to the gauge port on the liquid shutoff valve and purge the charging line between the refrigerant cylinder and the valve. Then open the valve to the mid position.

2 If the system is under a vacuum, stand the refrigerant drum

with the connection up, open the drum, and break the vacuum with refrigerant gas.

3 With a system gas pressure higher than the equivalent of a

freezing temperature, invert the charging cylinder and elevate the drum above the condenser. With the drum in

this position and the valves open, liquid refrigerant flows into the condenser. Approximately 75% of the total requirement estimated for the unit can be charged in this manner.

4 After 75% of the required charge enters the condenser,

reconnect the refrigerant drum and charging line to the suction side of the system. Again, purge the connecting line, stand the drum with the connection side up, and place the service valve in the open position.

Important: At this point, interrupt the charging procedure and do prestart checks before attempting to complete the refrigerant charge.

Note – Stamp the total operating charge per circuit on the unit

nameplate for future reference.

CAUTION

Adding refrigerant to the suction always risks liquid-related damage to the compressor.

30 McQuay IM 487-5

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