McQuay RAH 047C, RAH 077C, RDS 800C, RDS 802C Maintenance Manual

Installation and Maintenance Manual IM 987

RoofPak™ Applied Rooftop Systems Air Handler

RAH 047C - 077C, 12,000 to 50,000 cfm RDS 800C - 802C, 4000 to 20,000 cfm with MicroTech® III Unit Controller

Group: Applied Air Systems

Part Number: IM 987

Date: May 2009

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 . . . . . . . . . . . . . 44

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

Mechanical Installation . . . . . . . . . . . . . . . . . . . . . 52

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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

MicroTech III Controller Operation . . . . . . . . . . . 57

Using the Keypad/Display . . . . . . . . . . . . . . . 57

Passwords. . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Navigation Mode . . . . . . . . . . . . . . . . . . . . . . 58

Edit Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Legend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Unit Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Control Actuators . . . . . . . . . . . . . . . . . . . . . 84

Enthalpy Control . . . . . . . . . . . . . . . . . . . . . . 84

External Time Clock . . . . . . . . . . . . . . . . . . . 85

Smoke and Fire Protection . . . . . . . . . . . . . . 85

Smoke Detectors . . . . . . . . . . . . . . . . . . . . . 85

Emergency Shutdown . . . . . . . . . . . . . . . . . 86

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

Field Output Signals . . . . . . . . . . . . . . . . . . . 87

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

Duct High Pressure Limit . . . . . . . . . . . . . . . 88

Variable Frequency Drive Operation . . . . . . 88

Convenience Receptacle/Section Lights . . . 88 DesignFlow™ Outdoor Air Damper Option . 88

Propeller Exhaust Fan Option . . . . . . . . . . . 91

Exhaust Fan On/Off Control . . . . . . . . . . . . . 93

Ultraviolet Lights Option . . . . . . . . . . . . . . . . 94

Ultraviolet Light Operation . . . . . . . . . . . . . . 95

Check, Test, and Start Procedures . . . . . . . . . . . 96

Servicing Control Panel Components. . . . . . 96

Before Start-up . . . . . . . . . . . . . . . . . . . . . . . 96

Power Up . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Fan Start-up . . . . . . . . . . . . . . . . . . . . . . . . . 97

Economizer Start-up. . . . . . . . . . . . . . . . . . . 97

Heating System Startup . . . . . . . . . . . . . . . . 98

Air Balancing . . . . . . . . . . . . . . . . . . . . . . . . 98

Sheave Alignment . . . . . . . . . . . . . . . . . . . . 99

Drive Belt Adjustment . . . . . . . . . . . . . . . . . . 99

Mounting and Adjusting Motor Sheaves. . . 100

Final Control Settings. . . . . . . . . . . . . . . . . . . . . 103

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

Servicing Control Panel Components. . . . . 106

Planned Maintenance. . . . . . . . . . . . . . . . . 106

Unit Storage . . . . . . . . . . . . . . . . . . . . . . . . 106

Gas Furnace. . . . . . . . . . . . . . . . . . . . . . . . 107

Bearing Lubrication. . . . . . . . . . . . . . . . . . . 107

Setscrews . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Supply Fan Wheel-to-Funnel Alignment. . . 110

Winterizing Water Coils . . . . . . . . . . . . . . . 111

Control Panel Components . . . . . . . . . . . . 111

Replacement Parts List . . . . . . . . . . . . . . . . . . . 115

Replacement Parts . . . . . . . . . . . . . . . . . . . 115

Service and Warranty Procedure . . . . . . . . . . . 116

In-Warranty Return Material Procedure . . . 116

Limited Product Warranty (North America) . . . 117

Exceptions . . . . . . . . . . . . . . . . . . . . . . . . . 117

Assistance . . . . . . . . . . . . . . . . . . . . . . . . . 117

Sole Remedy . . . . . . . . . . . . . . . . . . . . . . . 117

Rooftop Equipment Warranty Regist. Form. . . 118

Introduction

RAH – 047 C S E

RoofPak

Unit Size RDS 800 = 4000 – 16,000 CFM RDS 802 = 8000 – 20,000 CFM RAH 047 = 12,000 – 30,000 CFM RAH 077 = 23,000 – 50,000 CFM

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

Design vintage

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

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.

Introduction

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

The MicroTech III applied rooftop unit controller is available. 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 Table 1).

Table 1: Program Specific Rooftop Unit Literature

Rooftop unit control configuration

McQuay 208 - 460 V OM 844-1

VFDs

Figure 1: Nomenclature

McQuay 575 V OM 895

Non-McQuay See vendor manuals

Operation manual

number

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.

McQuay IM 987 3

Introduction

Economizer

Filter

Heat

section

Supply fan

discharge

plenum

section

C19, 20

RAT

LT11 (optional)

S11, REC11

SD2

RAE

ACT3

PC5

OAE

VM1

LT10 (optional)

DAT

OAT

SV1, 2

(optional)

section

return air

(optional)

FS1

(optional)

SV5, 6 (optional)

S10, REC10 (optional)

SD1 (optional)

ACT6

Typical Component Locations

Figure 2 shows a typical unit with locations of major

components. These figures are for general information only. See the project’s certified submittals for actual specific dimensions and locations.

Control Locations

All controls are optional. If controls are ordered, Figure 2 shows the locations of the various control components

Figure 2: Control Locations

mounted throughout the units. See Figure 3, page 5 for the locations of control components mounted in control panels. Additional information is included in Table 2, page 12 and the wiring diagram legend, which is included in "Wiring

Diagrams"‚ page 59. Figure 2 shows the blow-through heat

and the blow-through coil sections.

4 McQuay IM 987

Control Panel

Main control panel

Electric heat control panel (optional)

Supply fan section

VFDs, line reactors, and

manual bypass (optional)

Prop exhaust VFDs

(not shown)

(optional)

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 from these figures depending on the particular unit options.

Figure 3: Control Panel Locations

Introduction

McQuay IM 987 5

Introduction

R24 R25 R28

R20 R26 R27 R28

R30

R45

R60

R69

R58

GCB1

Resistor

keypad

Remote

MCB

EHB1

ERB1

VFD remote

display

REC1

TB1

DHL

SPS1

SPS2

MMP60 MMP10 MMP20

R46

R48

HS1 S1

S7S4

Keypad display

Serial conn

M60

M10

M20

supply

Power

F1A

F1B

F1C

DS1

GND LUG DS1

TB7

blocks

remaining

TB2,

blocks

first seven

TB3,

detail, page 14.

See separate

SPS1,2 fittings

for static

pressure tubing

Figure 4: Typical Main Control Panel, Sizes 800C to 802C, 460 Volt

6 McQuay IM 987

Figure 5: Typical Main Control Panel, Size 047C, 460 Volt

VFD remote

display

GFR1

TB7

SPS1,2

fittings for

static pressure

tubing

TB2

F1A

F1B

F1C

Harness

Plugs

Introduction

McQuay IM 987 7

Introduction

Unit powered outlet and associated disconnect in seperate panel

Figure 6: Typical Main Control Panel, Size 077C, 460 Volt

8 McQuay IM 987

Introduction

M41 M42 M41

M33 M32 M31

FB33 FB32 FB31

FB43 FB42 FB41

PB3

SR2

SR3

SR1

TB11

Figure 7: TypicaL Gas Heat Panel, 1000 MBH

R22

TD10

R20

R23 R21

LS2

Figure 9: VFD Bypass Panel, 40 Hp, 460 Volt

LR10, 20

MMP30, 40

M30, 40

LS1

Figure 10: Electric Heat Panel, Sizes 800C, 802C

FSG

FSG Tim

Figure 8: TypiCal Propeller Exhaust Panel, 3 Fans, 460 Volt

McQuay IM 987 9

Introduction

GLG3

DS3

M41M43

FB41FB42FB43

H53

TB11

M31M32M33

FB31FB32FB33

M42

Figure 11: Electric Heat Panel, Size 047C Figure 12: Electric Heat Panel, Size 077C

FB31FB32FB33

M31M32M33

FB34FB44

M34M44

FB41FB42FB43

M41M42M43

GLG3

DS3

H53

TB11

10 McQuay IM 987

Figure 13: Harness Plug Connector Detail

LT OP1 LT OP2

LT11LT1 0

DFRH DFLH OPEN4

SD1 SD2

GSHT1 GSHT2

HL22 OPEN3

OAE PC7PC5

ACT3 OPEN2

SV12 SV56

AFD10 AFD20

FP1 OPEN1EPTS

RATS OATSDATS

Introduction

McQuay IM 987 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

Symbol Description Function Reset Location Setting Range Differential Part no.

DAT

DHL

EFT

FP1, 2

FS1

MCB

OAE

OAT

PC5

PC6

PC7

RAE

RAT

SD1

SD2

SPS1

Discharge air temperature sensor

Duct high limit switch

Entering fan air temperature sensor

Evaporator frost protection

Freezestat

Main control board

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

Processes input information

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

N/A

Auto

N/A

Auto

N/A

Auto

N/A N/A N/A 060004705

Auto

N/A

Manual

N/A

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

Discharge air

section

Return air

section

Main control

box

N/A N/A 060004705

3.5" w.c

(871.8 Pa)

N/A N/A 060004705

Opens at

30°F

Closes at

45°F

38°F (3°C)

or as

required

N/A N/A N/A 060006101

“B” or as required

Fully CW

past “D”

(when used

with RAE)

As required

.10" wc (25

Pa)

N/A N/A N/A 049262202

N/A N/A 060004705

N/A N/A N/A 04925001

N/A

0.05–5.0" wc

(12.5–1245.4

Pa)

N/A N/A 072501901

35°F–45°F

(2°C–7°C)

A–D

A–D N/A 049262201

.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 049545007

065493801

072502001

030706702

065493801

060015801

12 McQuay IM 987

Introduction

Table 2: Controls, Settings, and Functions (continued)

Symbol Description Function Reset Location Setting Range Differential Part no.

SPS2

Static pressure sensor duct #2

Static pressure sensor: building (space) pressure

System switch

ON-OFF-AUTO switch

Converts static pressure signals to voltage signals and sends them to MicroTech III controller

Converts static pressure signals to voltage signals.

Shuts off entire control circuit (except crankcase heaters)

Used to manually switch unit

N/A

Main control

box

Main control

box

Main control

box

Main control

box

N/A

N/A N/A N/A 001355000

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 049545007

N/A 049545006

McQuay IM 987 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 987

Figure 15: Service Clearances, Unit with SWSI Plenum Supply Fan

Roof

walkway

To roof

access

location

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

96"

(2438 mm)

60"

(1524 mm)

72"

(1829 mm)

72"

(1829 mm)

B C

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)

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

E F

Mechanical Installation

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:

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:

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 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 987 15

Mechanical Installation

24" (610 mm) Maximum

2" (51 mm)

Minumum

Top of Unit

to Overhead

Obstruction

24" (610 mm) Maximum

Overhead Canopy

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

Flue Box

Figure 16: Overhead Clearance

Figure 17: Side Discharge

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 987

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,

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,

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 view B

(Figure 19).

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 987 17

Mechanical Installation

Return

Air

"X"

Inside

87.00"

(2210 mm)

Inside

90.00"

(2286 mm)

94.75"

(2407 mm)

8.75"

(222mm)

See Detail "A"

70.75"

(1797 mm)

"Y"

Inside

81.00"

(2057 mm)

Inside

8.75"

(222 mm)

3.50"

(90 mm)

7.50"

(191 mm)

2.00"

(51 mm)

Supply

Air

3.50"

(90mm)

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.

Detail A

RAH unit

Dimensions X Y

in mm in mm

047C

38 965 28 711

077C with flat cooling coil and /or 44" SWSI plenum supply fan

157

38 965

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

157

46 1168

Main unit

curb

Unit base

Curb gasketing

2 × 4 nailer strip

Galvanized

curb

Cant strip (not furnished)

Roffing material

(not furnished)

Rigid insulation

(not furnished)Counterflashing

(not furnished)

Flashing (not furnished)

Figure 18: RAH Roof Curb Assembly Instructions

Figure 19: Roofing Detail “B”

18 McQuay IM 987

Figure 20: RDS Roof Curb Assembly Instructions

Return

Air

"X"

Inside

"Y"

Inside

85.00"

(2159 mm)

62.80"

(1594 mm)

"YY"

"XX"

See Detail "A"

38.80"

(984 mm)

20.00"

(508 mm)

Inside

76.00" (1930 mm) Inside

6.80"

(173 mm)

1.50"

(38 mm)

7.50"

(191 mm)

2.00"

(5.1 mm)

Supply

Air

Mechanical Installation

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

Unit size

800–802C

Return

X Y XX YY

fan

None 24.0 610 82.0 2083 6.8 173 1.5 38

McQuay IM 987 19

Mechanical Installation

Seismic hold down brackets

Structural steel frame

Spring isolator

Duct opening

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.

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 Figure 22 and Figure 23,

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, 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, 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, page 21). Welding must comply with weld fillet size, etc. as indicated in Figure 22, 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.

Figure 21: Typical Seismic Roof Curb (Spring Isolated)

20 McQuay IM 987

Figure 22: Welding Of Hold Down Brackets—Unit Base, Cross-Sectional View

Unit base

Seismic hold down bracket

Unit power wiring (by factory)

Unit control wiring (by factory)

High temp Insulation

Roof curb

Acceptable weld zone

Field attachment

weld

Weld zone

.25

.50"

Unit base

Seismic hold

down bracket

Unit power wiring

(by factory)

Unit control wiring (by factory)

Roof curb

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.

Figure 23: Shim Spacers On Hold Down Brackets

Mechanical Installation

McQuay IM 987 21

Mechanical Installation

2–48

Rail

.25

Unit power wiring (by factory)

Unit control wiring (by factory)

High temp insulation

Rail

Acceptable weld zone

Field attachment

weld

Weld zone

.50"

Unit base

6–12"

2–48

Rooftop unit

.25

Weld every 48"

6–12"

Rails

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 Figure 24 and Figure 25.

The total number of welds

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

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). Welding must comply with weld fillet size, etc. as indicated in Figure 24.

Note: High temperature insulation is installed at the factory to

CAUTION

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

Figure 25: Weld Locations for Rail Arrangement

22 McQuay IM 987

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

8.0

97.0

76.0

6.0

7.5

20.0

1.5

6.0

6.8

OPNG

2Typ

4Typ

OPNG

RPS only

Figure 26: Typical Power Wire Entrance, Curb View (RDS 800C–802C Shown (For Exact Values, Refer to Submittal)

McQuay IM 987 23

Mechanical Installation

99"

5" *

Max.

Note: Maximum recommended width for structural member is 5" (127

mm) to allow for 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.

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

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:

24 McQuay IM 987

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

6 Lifting Points

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)

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

Table 5: RDS X Dimension (See Figure 29) Outdoor/return Air Section

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)

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)

McQuay IM 987 25

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.

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

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

Phase I. Set sections

1 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.

26 McQuay IM 987

Phase II. Reassemble cabinet (Figure 31)

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

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

McQuay IM 987 27

Mechanical Installation

If applicable, install as shown with provided fasteners.

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

3.72 ref. (94 mm)

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

6 Reinstall the external raceway covers after routing of the

control wires is complete.

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.

3 Run the control harnesses by removing the external

4 Remove the excess harness length from the external

5 Make all electrical connections per the unit’s electrical

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.

raceway covers on either side of the unit split.

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.

schematics.

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.

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 987

Mechanical Installation

Piping Recommendations

1 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.

2 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.

3 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

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.

Leak Testing

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

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, page 30 shows the relationship between pressure,

microns, atmospheres, and the boiling point of water.

CAUTION

Before replacing refrigerant sensors or protective devices, see

"Refrigerant Charge"‚ page 31 for an important warning to

prevent an abrupt loss of the entire charge.

McQuay IM 987 29

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.

Take special care to add refrigerant slowly enough to the suction to prevent damage. Adjust the charging tank hand valve so liquid leaves the tank but vapor enters the compressor.

30 McQuay IM 987

+ 92 hidden pages

McQuay RAH 047C, RAH 077C, RDS 800C, RDS 802C Maintenance Manual

Specifications and Main Features

Frequently Asked Questions

User Manual