McQuay RDE076C Installation Manual

Installation and Mainenance Manual IM791-2

Applied Packaged Rooftop System Heating and Cooling with Evaporative Condenser

Gas/Electric Models RPE/RDE 076C-150C 76 to 150 Tons

Group: Applied Systems Part Number: IM791-2

Date: September 2010

Contents

Unit Nameplate............................................................ 3

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

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

Nomenclature....... ..................................................... ... 3

Unit Description........................................................... 4

Condenser Fan Arrangement ....................................... 5

Refrigerant Circuit Schematic ..................................... 5

Refrigeration Piping..................................................... 6

Spray System Plumbing with Optional Non-Chemical

Water Treatment .......................................................... 9

Bleed Off and Water Consumption ........................... 10

Control Locations ...................................................... 10

Walk-In Service Compartment.................................. 14

Receiving Inspection.................................................. 17

Unit Clearances.......................................................... 17

Ventilation Clearance ................................................ 18

Overhead clearance.................................................... 18

Roof Curb Assembly and Installation........................ 19

Reassembly of Split Units.......................................... 24

Condensate Drain Connection ................................... 26

Unit Piping................................................................. 26

Steam Coil Piping...................................................... 28

Steam Piping Recommendations ............................... 28

Steam Trap Recommendations.................................. 28

Damper Assemblies................................................... 30

Cabinet Weatherproofing........................................... 31

Installing Ductwork ................................................... 32

Installing Duct Static Pressure Sensor Taps.............. 33

Electrical Installation ........................................................ 34

Field Power Wiring.................................................... 34

Field Control Wiring.................................................. 37

Relief Damper Tie-Down .......................................... 38

Spring Isolated Fans....................................... ............ 38

Adjusting Spring Mounts........................................... 38

Spring Isolated Compressors..................................... 40

Power-up.................................................................... 41

Fan Operation ............................................................ 41

Economizer Operation............................................... 41

Heating....................................................................... 46

Legend ....................................................................... 47

Typical Control Schematic: Discharge Air Control

(DAC) ........................................................................ 50

Typical Control Schematic: Zone or Space Comfort Con-

trol (SCC).................................................... ............... 52

Typical Output Schematic: Actuator Control ............ 54

Typical Schematic: Condenser Fan, Anti-Corrosion Elec-

tric Heaters ................................................................ 55

Typical Output Schematic: VFD Control (SAF/RAF) 56 Typical Output Schematic: VFD Control Continued

(SAF/RAF)................................................................. 57

Typical Power Circuit Wiring - 4 Compressor - VFD 58 Typical Condensing Unit Control - MicroTech II - 4

Compressor................................................................. 60

Typical Super Mod Gas Furnace Control (1000 MBh) 64

Non-Chemical Water Treatment ................................ 66

Enthalpy Control ........................................................ 66

Hot Gas Bypass .......................................................... 68

External Time Clock................................................... 68

Smoke Detectors......................................................... 68

Freeze Protection........................................................ 68

Low Airflow Alarm.................................................... 69

Duct High Pressure Limit........................................... 69

Condensing Unit VFD Operation.... ........................... 69

Variable Frequency Drive Operation ......................... 69

Convenience Receptacle/Section Lights .................... 69

DesignFlow™ Outdoor Air Damper Option.............. 69

Propeller Exhaust Fan Option .................................... 72

Propeller Exhaust Fan Control ................................... 74

Ultraviolet Lights Option ........................................... 76

Ultraviolet Light Operation........................................ 76

Before Start-Up........................................................... 78

Power-Up.................................................................... 79

Fan Start-Up ............................................................... 79

Economizer Start-Up.................................................. 79

Evaporative Condenser Start-Up................................ 79

Compressor Start-Up.................................................. 80

Oil Pressure ................................................................ 81

Heating System Start-Up............................................ 81

Air Balancing.............................................................. 82

Sheave Alignment ...................................................... 82

Drive Belt Adjustment................................................ 83

Mounting and Adjusting Motor Sheaves.................... 83

Rooftop Equipment Warranty Regist. Form...................... 86

Planned Maintenance.............................................. .... 93

Sump Cleaning ............................. .............................. 95

Unit Storage................................................................ 95

Gas Furnace................................................................ 96

Bearing Lubrication.................................................... 96

Setscrews.................................................................... 98

Supply Fan Wheel-to-Funnel Alignment ................... 99

Refrigerant Charge ................................... .................. 99

Replacing Failed Refrigerant Sensors

or Switches ............................................................... 100

Evaporative Condenser Section................................ 100

Control Panel Components....................................... 101

Limited Product Warranty............................................... 104

Service and Warranty Procedure ..................... ................ 104

Replacement Parts .................................................... 104

Compressor....................................................... ........ 105

In-Warranty Return Material Procedure................... 105

Introduction

This manual provides general information about the “C” vintage McQuay RoofPak applied rooftop unit, models RDE and RPE. 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 and requirements, and service procedures, refer to IM696 for a description of operation and information on using and programming the MicroTech II unit controller, refer to the appropriate operation manual (see Figure 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 Figure 1).

Table 1: Operation Manuals

Unit Manual

VFD’s Vendor IM Manuals

Discharge Air Control (VAV or CAV) OM 137

Space Comfort Control

(CAV-Zone Temperature Control)

Non-Chemical Water Treatment Option IM 827

OM 138

Introduction

Unit Nameplate

The unit nameplate is located on the outside lower right corner on the main control box door. It includes the unit model number, serial number, unit part number, electrical characteristics, and refrigerant charge.

Gas Burner Nameplate

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

Hazard Identification Information

WARNING

Warnings are provided throughout this manual to indicate to installing contractors, operators, and service personnel potentially hazardous situatio n s wh i c h, if no t avo i d ed , ca n result in severe personal injury or property damage.

CAUTION

Cautions are provided throughout this manual to indicate to installing contractors, operators, and service personnel potentially hazardous situatio n s wh i c h, if no t avo i d ed , ca n result in personal injury or equipment damage.

Nomenclature

RoofPak

Unit Configuration

P = Blow through Cooling D = Draw through Cooling

Evaporative Condensers

Nominal Capacity (Tons)

RPE, RDE: 076, 089, 100, 110, 130, 140, 150

R P E - 150 C S E

Heat Medium

A = Natural Gas E = Electric S = Steam W = Hot Water Y = None (Cooling Only)

Cooling Coil Size

S = Standard (Low Airflow) L = Large (High Airflow)

Design Vintage

McQuay IM 791-2 3

Introduction

Unit Description

Typical Component Lo ca tio ns

Figure 1 shows a typical RPE unit with the locations of the

major components. Figure 2, page 4 shows a typical RDE unit

Figure 1: Typical Component Locations - RPE Units

with the locations of the major components. These figures are for reference only. See the certified submittals for actual specific dimensions.

Figure 2: Component Locations - RDE Units

4 McQuay IM 791-2

Condenser Fan Arrangement

Table 2 shows the condenser fan numbering conventions and

locations for each unit size.

Table 2: Condenser Fan Arrangement

Introduction

Unit Size

076C 089C 100C

110C 130C 140C 150C

Refrig. Circuit

Arrangement

Refrigerant Circuit Schematic

Figure 3: Circuit Schematic

Fan Control With VFD Without VFD

11, 21 - Digital 12 - CCB1 - B06 22 - CCB2 - B06

11, 21 - Digital 12 - CCB1 - B06 22 - CCB2 - B06 31 - CCB1 - B07 32 - CCB1 - B07

11, 21 - Digital 21 - CCB2 - B05 12 - CCB1 - B06 22 - CCB2 - B06

11 - CCB1 - B05 21 - CCB2 - B05 12 - CCB1 - B06 22 - CCB2 - B06 13 - CCB1 - B07 23 - CCB2 - B07

Legend

A Compressor A1 Second Compressor (4 Compressor Units) B Discharge Line C Condenser Coil D Evaporator Coil

E Manual Shut-off Valve

F Filter-Drier G Liquid Line Solenoid Valve H Sightglass I Liquid Line

J Suction Line K Thermostatic Expansion Valve L Distributor

M Combination Hot Gas Bypass Control and Solenoid Valve

N Hot Gas Bypass Lines (Optional)

McQuay IM 791-2 5

Introduction

Refrigeration Piping

This section presents the unit refrigeration piping diagrams for the various available configurations. Component numbering conventions are also shown.

Figure 4: Condenser Piping - 2 Compressors - 2 Circuits (076C - 100C)

1. Discharge Line Service Valve

2. Discharge Muffler

3. Liquid Line Manual Shut-off Valve

4. Suction Line Service Valve

5. Vibration Eliminator

Suction LIne Circuit 2 Circuit 1

Compressor 2

Discharge Line Circuit 2

Hot Gas Bypass Circuit 2 Circuit 1

Liquid Line Circuit 1

Liquid Line Circuit 2

With Vibration Eliminators

Compressor 1

Discharge Line Circuit 1

Suction LIne Circuit 2 Circuit 1

Compressor 2

Discharge Line Circuit 2

Hot Gas Bypass Circuit 2 Circuit 1

Liquid Line Circuit 1

Liquid Line Circuit 2

Compressor 1

Without Vibration Eliminators

Discharge Line Circuit 1

6 McQuay IM 791-2

Figure 4. Condenser Piping - 4 Compressors - 4 Circuits (110C - 150C)

1. Discharge Line Service Valve

2. Discharge Muffler

3. Liquid Line Manual Shut-off Valve

4. Suction Line Service Valve

5. Vibration Eliminator

Hot Gas Bypass Circuit 2 Circuit 1

Liquid Line Circuit 2

Liquid Line Circuit 1

Suction LIne Circuit 2 Circuit 1

Compressor 4

Compressor 2

Introduction

Discharge Line Circuit 2

Compressor 3

With Vibration Eliminators

Hot Gas Bypass Circuit 2 Circuit 1

Liquid Line Circuit 2

Liquid Line Circuit 1

Compressor 1

Suction LIne Circuit 2 Circuit 1

Discharge Line Circuit 1

Compressor 4

Compressor 2

Discharge Line Circuit 2

Compressor 3

Without Vibration Eliminators

Compressor 1

Discharge Line Circuit 1

McQuay IM 791-2 7

Introduction

Figure 5: Service Compartment Piping

Solid Core Filters

1. Liquid Line Solid Core Filter/Drier

2. Liquid Solenoid Valves

3. Hot Gas Bypass Valve and Solenoids

To Evaporator Coil

Liquid Line Circuit # 1 Circuit # 2

Suction Line Circuit # 2 Circuit # 1

Hot Gas Bypass Circuit # 1

Hot Gas Bypass Circuit # 2

To Compressors

Replaceable Filters

1. Liquid Line Replaceable Core Filter/Drier

2. Liquid Solenoid Valves

3. Hot Gas Control and Solenoid Valve

To Compressors

To Evaporator Coil

Liquid Line Circuit # 1 Circuit # 2

Suction Line Circuit # 2 Circuit # 1

Hot Gas Bypass Circuit # 1

Hot Gas Bypass Circuit # 2

8 McQuay IM 791-2

Spray System Plumbing with Optional Non-Chemical Water Treatment

WARNING

Failure to maintain and continually provide water treatment may result in severe equipment damage and may create biologically hazardous conditions. See

Figure 26 for water connection sizes and locations.

Figure 6: Spray System Piping

NOTE: The cyclone separator is on a side stream. A hand

valve controls water flow. The hand valve should be opened until the inlet pressure to the separator is about 12 psi as determined by the factory-installed gauge. This will yield about 20 gpm of blowdown whenever the blowdown solenoid opens.

Dolphin makeup water

Dolphin sump water treatment module

Dolphin sump water transformer

To Spraybar

transformer

Introduction

To Spraybar

Conductivity sensor

Conductivity controller

Makeup water control valve

Auto purge controller

Flowmeter

Cyclone seperator

Sump overflow

Ball valve actuators

Heat-tape all components from customer connection point to makeup water control valve

Dolphin makeup water treatment module

Makeup water connection point to sump tank.

Cleanout

Customer makeup water connection point

Manual shutoff

Sump Pump

McQuay IM 791-2 9

Freeze protection valve and actuator

Blow down and drain

Introduction

Bleed Off and Water Consumption

Controlled bleed off [or blow down] is required on McQuay RPE/ RDE units as it should be with all evaporative condensing products. It involves draining off a portion of the highly concentrated water from the bottom of the sump and replacing it with lower concentration make-up water to inhibit scale. Scale protection is required because the evaporation process leaves behind solids (scale) that will coat the heat exchanger surfaces and sump. This reduces the capacity, efficiency, and life expectancy of the equipment.

Manual bleed off occurs whenever the spray pump operates. A manual valve adjusts flow and is provided as standard. Refer to Figure 6. This inevitably bleeds off too much [increased water costs] or too little [risking scale build up] water. Automatic bleed off control is superior and usually is provided with the water treatment system.

Theoretical water consumption required for proper heat rejection is 1.8 gallons per ton hour. All of this water evaporates and none goes into the sewer. An additional 0.6 to

0.9 gallons per ton hour (.03 to .05 with McQuay nonchemical water treatment) is also required for make up and bleed off. The exact amount should be determined by water

Figure 7: Control Locations - RPE Units

analysis. The RPE/ RDE includes a float valve and solenoid that automatically refills the sump as required.

Bleed off must be handled in accordance with local codes and normally is drained into the sanitary sewer. Normally, this water should not be drained onto the roof or into a storm drain. One possible exception to this is with the McQuay nonchemical water treatment option (consult local codes carefully). Because most water utilities charge for both intake and sewer water flows based on intake meter readings, sewer charges may be reduced if sewer flow is proven to be less than water intake. McQuay offers both intake and bleed off water meters to document reduced sewer flow [confirm details with your local utility]. These meters are not included in the basic water treatment option.

Control Locations

Figure 7 (RPE Units) and Figure 8, page 11 (RDE Units) show

the locations of the various control components mounted throughout the units. See Control Locations‚ page 10 for the locations of control components mounted in control panels. Additional information is included in Table 3, page 15 and the

Legend‚ page 47.

Return Air

Economizer

Heat

Section

Discharge

Plenum Section

HL22 (Optional)

LT10 (Optional)

S10, REC10 (Optional)

Service Section

SD1 (Optional)

Condensor

Section

VM1 (Optional)

Exhaust Fan

Water Treatment (Optional)

Oil Pressure Box

Water Pump

Control Box

Space Heater (Optional)

Water Level Switches (WL63, WL64)

Sump Heater (Optional)

Sump Water Temp Sensor

ACT5 (optional)

ACT6 (optional)

OAT

LT11

(Optional)

S11 REC11

OAE

RAE (optional)

10 McQuay IM 791-2

Figure 8: Control Locations - RDE Units

(

)

ondensor Section

Introduction

C19,20

(Optional)

Economizer

Return Air

Filter

Section

Heat

Section

SV1, 2

Supply Fan

Discharge

Plenum Section

OAE

OAT

Service Section

FS1

(Optional)

LT10 (Optional)

S10, REC10 (Optional)

SD1 (Optional)

Exhaust Fan

Water Treatment (Optional)

Water Pump

Control Box

Space Heater (Optional)

Sump Heater (Optional)

Sump Water Temp Sensor

Oil Pressure Box

Water Level Switches (WL63, WL64)

LT11 (Optional)

S11, REC11

SD2

Optional

McQuay IM 791-2 11

Introduction

Control Panel Locations

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. See Wiring Diagrams‚ page 47 for the Legend and component description.

Figure 9: Control Panel Locations - Service Compartment

WARNING

Electrical shock can cause severe personal injury or death.

The control panel must be serviced by trained, experienced technicians.

Oil Pressure Instruments

Control Panel

Power Disconnect

12 McQuay IM 791-2

Figure 10: Main Control Panel - 076C - 150C

Introduction

See page page 47 for Legend

for Control

Connections

Terminal Block

2 Feet to Floor

Main Disconnect

or Power Block

McQuay IM 791-2 13

Introduction

Figure 11: Electric Heat Control Panel - Sizes 075C- 135C

FB31FB32FB33

M31M32M33

FB34FB44

M34M44

FB41FB42FB43

M41M42M43

GLG3

DS3

H53

TB11

• The manual shutter is normally be closed but can be opened

to condition the compartment when service is needed.

Figure 12: Walk-In Service Compartment

Perform Most Refrigerant Service in Comfort, Away

From Compressor Noise

Marine Lights

Exhaust Fan

Optional Unit Heater

Walk-In Service Compartment

Each unit includes a walk-in service compartment containing the following:

• Main control panel. See Figure 9, page 12.

• Liquid Line components except the expansion valve.

• Spray pumps, water control valves (except float valves in the

sump) and water supply and sanitary connections. See

Figure 6, page 9.

• Water treatment system (optional).

• Main access door opened from the inside and outside.

• Raised service grate to help protect service personnel against

water and chemical spills.

• Refrigerant Schrader ports are provided on the liquid and

suction lines to allow for easy refrigerant pressure readings, however, discharge pressure at the compressor must be measured outside the enclosure.

• Refrigerant charge can be added at the Schrader connections

in the compartment.

• Lights, ventilation fans, manual shutter that can be opened to

allow conditioned air into the plenum and optional unit heater provide more comfortable servicing.

• An adjustable TC66 thermostat turns on the ventilation fan

when the compartment temperature exceeds 75°F.

• An adjustable integral thermostat runs the unit heater when

the compartment temperature drops to 35°F.

Charging, Suction, Discharge & Liquid Schrader Connections

Hot Gas Bypass Valves

Solenoid, Sight Glass & Filter Drier

Raised Floor Grate and Drain Pan

Space for Water Treatment

WARNING

Moving parts and electrical connections in the service compartment can cause severe personal injury or death.

Cabinet access must be limited to trained, experienced technicians only.

14 McQuay IM 791-2

Controls, Settings, and Functions

Introduction

Table 3 presents a listing of all the unit control devices.

Included in the table are the device symbol, a description of the device, its function, and any reset information, its location,

Table 3: Controls, Settings , an d Fu nc tions

Symbol

CS1 & 2

DAT

DHL

EFT

FP1, 2

FS1 Freezestat

HP1, 2,

3 & 4

LP1, 2

MCB Main control board Processes input information N/A

MP1–6 Compressor motor

OAE

OAT

PC5 Dirty filter switch Senses filter pressure drop Auto

PC6 Dirty filter switch Senses filter pressure drop Auto

Description Function Reset Location Setting Range Differential Part no.

Switch (toggle), refrigerant circuit

Discharge air temperature sensor

Duct high limit switch

Entering fan air temperature sensor

Evaporator frost protection

High pressure control

Low pressure control

protector

Enthalpy control (electromechanical)

Enthalpy control (electronic)

Outside air temperature sensor

Shuts off compressor control circuits manually

Senses discharge air temperature

Prevents excessive VAV duct pressures; shuts off fan

Senses entering fan air temperature

Senses low refrigerant temperature

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

Stops compressor when refrigerant discharge pressure is too high

Stops compressor when suction pressure is too low (used for pumpdown)

Senses motor winding temperature, shuts off compressor on high temperature.

Notes:

1.Unit size 018C compressors include internal motor protector.

2.Unit sizes 020C–036C, circuit #1 compressors include internal motor protector (refer to unit wiring diagram).

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 N/A N/A N/A 060004705

N/A

Auto

N/A

Auto Heating section

Manual

(relay

latched)

Auto Compressor

Auto at

3400

ohms

Auto

any device setting, any setting ranges, differentials, and the device part number.

Main control

panel

Discharge air

section

Main control

panel

Inlet of supply

fan

Return bends of

evaporative coil

Compressor

Main control

box

Compressor junction box

Economizer

section

Economizer

section

First filter

section

Final filter

section

N/A N/A N/A 01355000

N/A N/A 060004705

3.5" w.c

(871.8 Pa)

N/A N/A 060004705

Opens at

30°F

Closes at

45°F

38°F (3°C)

or as required

See

page 105.

See

page 105.

N/A N/A N/A 060006101

9 K–18 K

ohms

“B” or as

required

Fully CW past

“D”

(when used

with RAE)

As required

0.05–5.0" wc

(12.5–1245.4

Pa)

N/A N/A 072501901

35°F–45°F

(2°C–7°C)

N/A

700 ohms cold N/A 044691509

A–D

A–D N/A 049262201

.05-5" wc

(12.5–1245.4

Pa)

.05-5" wc

(12.5–1245.4

Pa)

.05" wc

(12.5 Pa),

fixed

12°F (7°C),

fixed

100 psi

(689 kPa)

25 psi

(172 kPa)

Temperature:

3.5°F (2°C) Humidity:

5% fixed

.05" wc

(12.5 Pa)

.05" wc

(12.5 Pa)

065493801

065830001

047356120

047356111

030706702

065493801

McQuay IM 791-2 15

Introduction

Table 3: Controls, Settings , an d Fu nc tions (continued)

Symbol

PC7

PS1, 2 Pumpdown switch

RAE

RAT

SD1

SD2

SPS1

SPS2

SUMP

HTR

SV1, 2

SV5, 6

SV61,

SV63 Solenoid Valve

SWT Sump Water Temp

S1 System switch

TC66 Temperature

WL63 Switch, Water Level

WL64 Switch, Low Water Maintains proper water level N/A Sump Holding

Description Function Reset Location Setting Range Differential Part no.

Airflow proving switch

Return air enthalpy sensor

Return air temperature sensor

Smoke detector, supply air

Smoke detector, return air

Static pressure sensor duct #1

Static pressure sensor duct #2

Static pressure sensor: building (space) pressure

Sump Water Heater , Evap Condenser

Solenoid valve (liquid line)

Solenoid valve (hot gas bypass)

Solenoid Valve (Water Fill - Evap Cond)

(Sump Drain - Evap Cond)

Sensor

ON-OFF-AUTO switch

Control - Evap Cond Exhaust Fan

Sump Fill

Senses supply fan pressure to prove airflow

Used to manually pump down compressor

Used to compare return air enthalpy to outside air enthalpy (used with OAE)

Senses return air temperature N/A Initiates unit shutdown if smoke

is detected Initiates unit shutdown if smoke

is detected Converts static pressure

signals to voltage signals Converts static pressure

signals to voltage signals and sends them to MicroTech II controller

Converts static pressure signals to voltage signals.

Controls Wa ter Temp in the Evap Condenser Sump

Closes liquid line for pumpdown

Closes hot gas bypass line for pump-down

Open when sump water level is

low to add water

Opens to drain sump N/A Service

Sensor for freeze and head

pressure control

Shuts off entire control circuit (except crankcase heaters)

Used to manually switch unit N/A

Sequences the vestibule

exhaust fan

Maintains proper water level N/A Sump Holding

Auto

N/A

Manual

N/A

N/A N/A Service

N/A Sump Holding

N/A

N/A Service

Supply fan

section

Condenser control box

Economizer

section

Return air

section

Discharge air

section

Return air

section

Main control

box

Main control

box

Main control

box

Sump Holding

Tank

Condenser

section

Condenser

section

Compartment

Tank

Main control

box

Main control

box

Compartment

Tank

.10" wc (25

Pa)

N/A N/A N/A 01355000

N/A N/A N/A 049262202

N/A N/A 060004705

N/A N/A N/A 04925001

N/A

N/A N/A N/A

N/A N/A N/A 111011001 N/A N/A N/A

N/A N/A N/A

N/A N/A N/A See parts

N/A N/A N/A 001355000

N/A N/A N/A N/A N/A N/A

N/A N/A N/A See parts

.05-5" wc

(12.5–1245.4

Pa)

0–5" wc

(0–1245.4 Pa)

1–6 VDC out

0–5" wc

(0–1245.4 Pa)

1–6 VDC out

-025–0.25" wc

(-62.3–62.3 Pa)

1–5 VDC out

.05" wc

(12.5 Pa),

fixed

N/A 049545007

N/A 049545006

060015801

See parts

catalog

16 McQuay IM 791-2

Mechanical Installation

The installation of this equipment must 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.

WARNING

Improper installation, adjustment, alteration se r v ic e or maintenance can cause personal inju ry or death.

Read and understand this Installation and Maintenance manual thoroughly before installing or servicing this equipment.

Note: Low head pressure may lead to poor, erratic refrigerant

feed control at the thermostatic expansion valve. The units have automatic control of the condenser fans which should provide adequate head pressure control down to 50°F (10°C). The system designer is responsible for assuring the condensing section is not exposed to

excessive wind or air recirculation.

WARNING

Sharp edges and coil surfaces can cause personal injury. Avoid contact with them.

Installation and maintenance must be performed only by trained and experienced personnel familiar with local codes and regulations.

WARNING

Sharp edges on sheet metal, screws and clips can cause personal injury.

This equipment must be installed and operated only by experienced trained personnel.

Mechanical Installation

Receiving Inspection

When the equipment is received, check all items 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.

Inspect all units for damage when received. Report all shipping damage to the carrier and file a claim. In most cases, equipment is shipped F.O.B. factory and claims for freight damage should be filed by the receiver.

The unit nameplate should be checked before unloading the unit to make sure the voltage complies with the power supply available.

Unit Clearances

Service Clearance

Allow service clearance approximately as indicated in

Figure 13. Also, a roof walkway should be provided to the

rooftop unit and along at least the two sides of the unit that provide access to most controls and serviceable components.

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.

Figure 13: Service Clearances Side Discharge

72" 4 sides except as indicated

ABCDEFG

24"

Roof Walkway

Adjacent to Cooling Coil, Heat, and Supply Fan Sections.

ervice Clearance on

Legend:

A = Return Air Section B = Filter Section C = Cooling Section D = Cooling/Supply Fan Section E = Heat Section F = Discharge Plenum Section G = Service Com

artment

72" Clearance to end of unit or en of outside hood

McQuay IM 791-2 17

Mechanical Installation

Maxi

All

Figure 14: Side Discharge

V entilation Clearance

Following 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 Service Clearance‚ page 17. See also

Figure 13, page 17.

3 The distance between any two units within a screen or

fence should be at least 120" (3048 mm).

Unit(s) surrounded by solid walls:

1 If there are walls on one or two adjacent sides of the unit,

the walls may be any height. If there are walls on more than two adjacent sides of the unit, the walls should not be higher than the unit.

2 The distance between the unit and the wall should be at

least 96" (2438 mm) on all sides of the unit.

3 The distance between any two units within the walls should

be at least 120" (3048 mm). Do not locate outside air intakes near exhaust vents or other sources of contaminated air.

If the unit is installed where windy conditions are common, wind screens should be installed around the unit, maintaining the clearances specified (see Figure 15). This is particularly important to prevent blowing snow from entering outside air intakes, and to maintain adequate head pressure control when mechanical cooling is required at low outdoor air temperatures.

Overhead clearance

1 Unit(s) surrounded by screens or solid walls must have no

overhead obstructions over any part of the unit.

2 The area above the condenser must be unobstructed in all

installations to allow vertical air discharge.

3 The following restrictions must be observed for overhead

obstructions above the air handler section (see Figure 15):

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 2" (51 mm)

above the top of the unit.

c There must be no overhead obstructions in the areas

above the outside air and exhaust dampers that are farther than 24" (610 mm) from the side of the unit.

Figure 15: Overhead Clearance

mum

owable

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

24" (610 mm) Maximum

2" (51mm) Top of Unit To O verhead Obstruction

Overhead Canopy Area

Flue Box

18 McQuay IM 791-2

Mechanical Installation

Roof Curb Assembly and Installation

The roof curb and unit must be located 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 could allow the transmission of sound and vibration into the occupied space, the unit should be

located 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.

The curb and unit must be installed level to allow the condensate drain to flow properly.

Integral supply and return air duct flanges are provided with the RPE/RDE roof curb, allowing connection of ductwork 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 ductwork. Refer to Installing Ductwork‚ page 32 for details on duct connections. It is critical that the condensate drain side of the unit be no higher than the opposite side.

Assembly of a typical RPE/RDE roof curb is shown in

Figure 17, page 21. Parts A through K 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.

RPE/RDE Assembly instructions

Refer to Figure 17, page 21.

1 Set curbing parts A through K per dimensions shown over

roof opening or on a level surface. 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. 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 W eld curbing in place. Caulk all seams watertight. Remove

backing from 0.25" (6 mm) thick x 1.50" (38 mm) wide gasketing and apply to surfaces shown by notes.

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.

McQuay IM 791-2 19

Mechanical Installation

Figure 16: RPE/RDE Roof Curb Assembly

RDE & RPE 076-100

OPENING

SEE FIGURE "A"

RDE & RPE 110-150

OPENING

SEE FIGURE "A"

Dim 076-100C 110-150C

100.00 100.00

84.00 60.00

62.00 62.00

38.00 46.00

87.00 87.00

1.50 1.50

6.80 6.80

81.00 81.00

7.50 7.50

5.00 5.00

8.00 8.00

2.00 2.00

4.00 4.00

1.50 1.50

78.80 78.80

B C D E F G H

K L M N P Q R

20 McQuay IM 791-2

Figure 17: RPE/RDE Roof Curb Assembly

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

Equal Length Side Supports

See Detail "A"

Mechanical Installation

Condenser

Section Support

(1 of 2 shown)

38.8"

Return

Air

85"

62.8"

Section B-B

Section A-A

1. Unit Base

2. Curb Gasketing

3. 2 x 4 Nailer Strip

4. Galvanized Curb

5. Duct Support

6. Cant Strip (not furnished)

7. Roofing Material (not furnished)

8. Rigid Insulation (not furnished)

9. Counter flashing (not furnished)

10. Flashing (not furnished)

McQuay IM 791-2 21

Mechanical Installation

Post and Rail Mounting

When mounting by post and rail, the structural support should be run the full length of the unit. Locate the structural member at the base of the unit as shown in Figure 18 assuring the

shaded area 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. Properly seal cabinet penetrations (electrical, piping, etc.) to protect against moisture and weather.

Figure 18: Post and Rail Mounting

max

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 19 shows an example of the rigging instruction label

shipped with each unit.

WARNING

Use all lifting points. Severe personal injury and property damage can result from improp er lifting adjustment.

Figure 19: Rigging and Handling Instruction Label

Rigging and Handling Instructions

Unit has either four or six lifting points (four-point shown below).

Caution: All lifting points must be used.

Rigging cables must be at least as long as distance "A".

Note:

*Rail cannot extend beneath the unit more than 5" (127 mm) or it will interfere with duct and electrical connections.

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 must be stored at the construction site for an intermediate period, these additional precautions should be taken:

1 Make sure to support the unit well along the length of the

base rail.

2 Make sure to level the unit

(no twists or uneven ground surface).

3 Provide proper drainage around the unit to prevent flooding

of the equipment.

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

Lifting Points

Refer to Figure 20 and the following calculations to determine whether a four or six point lift is required.

X= Distance from the entering air end of the unit (or shipping section) to the first lifting lug in the direction of air flow.

For all units or shipping sections with outdoor air/return air options, X= 48"

For shipping sections without outdoor air/return air options,

X= 0 Y= distance from condenser or leaving air end of unit to the

last lifting lug. For all units or shipping sections with condensers, Y= 21.5

(sizes 76-100) or Y= 60.2 (sizes 110-150). For all units or shipping sections without condensers, Y=0 Z= Total base rail length of the unit. Note: Z excludes hoods

and overhung parts extending past base rails of the unit.

22 McQuay IM 791-2

Mechanical Installation

A= Z-X-Y If A<288", 4-point lift is sufficient If A>288", 6-point lift is required B= Distance from first lifting lug to middle lifting lug on units

with 6-point lift. B= A/2 +/- 48" Note: Middle lifting lug may be installed on

either side of the midpoint to avoid interference with condensate drains.

Figure 20: Unit Type RPE/RDE Lifting Points

Figure 21: RPE/RDE Factory Split at Supply Fan Section

McQuay IM 791-2 23

Mechanical Installation

Reassembly of Split Units

Although RoofPak units typically ship from the factory as complete units, they may be split at the factory.

The RPE/RDE unit may ship from the factory as two pieces, split at the supply fan bulkhead, to be recoupled together on the roof. This configuration would be ordered if shipping length or weight limitation prevented a packaged RPE/RDE from being ordered. Splitting at the fan has the advantage of leaving all factory refrigerant piping intact so field evacuation and charging is not required.

A single nameplate is attached to the air handler section and power is fed to both sections through the main control box, as it would be in a non-split RPE/RDE unit.

RPE/RDE Factory Split at Fan

Field reassembly of an RPE/RDE unit that has shipped split at the fan takes place in two phases:

Phase 1 - Setting the Sections and Cabinet Reassembly

The steps required to set the unit and reassemble the cabinet are shown in Figure 22, Figure 23, and Figure 24, page 25. The following items should be noted:

1 Top cap and plywood covers must be removed before the

sections are set together, but the steel retainer clips must be left in place to secure the bulkhead. Refer to Step 1 and

Figure 22.

2 Both sections must be carefully lowered into place to make

sure that the roof curb engages the recesses in the unit base.

3 All seams at the split must be caulked watertight after

recoupling the sections, as shown in Step 3 and Figure 23,

page 25.

WARNING

Improper installation can cause severe equipment damage, personal injury or death.

Connect the power block correctly and maintain proper phasing.

When reconnection of the power wires is complete, the inner raceway cover in the blank or heat section must be reinstalled.

Figure 24, page 25 shows a typical installation of the raceway

cover. If the unit is equipped with a fan diffuser, install as shown in Figure 24.

Control harnesses can be run by removing the external raceway covers on either side of the unit split. The excess harness length can be removed from the external raceway on the DX side of the split, routed 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. All electrical connections should be made per the unit's electrical schematics. Reinstall the external raceway covers after routing of the control wires is complete.

1 Prepare the units for reassembly as shown in Figure 22.

Figure 22: RPE/RDE Split at Fan Reassembly - Step 1

R e m o v e p l y w o o d a n d r e t a i n i n g

R e m o v e t o p c a p a n d s a v e f o r s t e p 3

a n g l e s f r o m u n i t a n d d i s c a r d

D i s c h a r g e e n

d o f U n i t

Phase 2 - Reconnecting Power and Control Wiring

The DX coil/condenser section contains power and control harnesses which have their excess length in the blank or heat section that is normally immediately downstream of the fan. Once the sections are physically reconnected, the ends of the

F a n e n d o f U n i t

power harness are fed back through the unit base into the junction box, per the unit’s electrical schematics.

24 McQuay IM 791-2

Set fan end of unit and discharge end of unit in place.

3 Caulk and install parts as shown in Figure 23.

R e m o v e s c r e w s o n f a n p a n e l , b u t l e a v e r e t a i n e r c l i p s i n p l a c e ; s a v e s c r e w s f o r

S t e p 3 .

Mechanical Installation

ovided

Figure 23: Split at Fan Reassembly - Step 3

Reinstall Top Cap Saved from Step 1

Caulk Ends of Splice Cap

Splice Cover Provided

Install #10 Screws Provided

Figure 24: RPE Split at Fan Reassembly - Step 4

Install Screws (.250-20 x .75) Saved from Step 1

Nut Clip-on Pr

Make electrical connections and reinstall Inner Raceway Cover as shown in Figure 24.

McQuay IM 791-2 25

Mechanical Installation

Condensate Drain Connection

The unit is provided with a 1.5" male NPT condensate drain connection. Refer to certified drawings for the exact location. The unit and drain pan must be level side to side and a P-trap must be installed for proper drainage.

RPE units may have positive or negative pressure sections. Traps should be used in both cases, with care given to negative pressure sections. In Figure 25, page 26, dimension “A” should be a minimum of 8" (203 mm). So the cabinet static pressure does not blow or draw the water out of the trap and cause air leakage, dimension A should be two times the maximum static pressure encountered in the coil section in inches w.c.

Drainage of condensate directly onto the roof may be acceptable; refer to local codes. A small drip pad of stone, mortar, wood or metal be should be provided to protect the roof against possible damage.

If condensate is to be piped into the building drainage system, the drain line should be pitched away from the unit at a minimum of 1/8" per foot. The drain line must penetrate the roof external to the unit. Refer to local codes for additional requirements. Sealed drain lines require venting to provide proper condensate flow.

Where the cooling coils have intermediate condensate pans on the face of the evaporator coil, copper tubes near both ends of the coil provide drainage to the main drain pan. Check that the copper tubes are in place and open before the unit is put into operation.

Because drain pans in any air conditioning unit will have some moisture in them, algae, etc. will grow. Periodic cleaning is necessary to prevent this buildup from plugging the drain and causing the drain pan to overflow. Also, the drain pans should be kept clean to prevent the spread of disease. Cleaning must

be performed by qualified personnel.

WARNING

Clean drain pans regularly. Growth in uncleaned drain pans can cause disease.

Cleaning must be done by trained, experienced personnel.

Figure 25: Condensate Drain Connection

S e e V i e w " A "

C o p p e r T u b e

( o n e e a c h e n d o f c o i l )

S t a t i c P r e s s u r e " P "

4 " ( 1 0 2 m m )

M i n i m u m

" A "

8 " ( 2 0 3 m m )

M i n . o r 2 x " P "

( i n . w . o . )

D r a i n P a n

N o t e : D r a i n l i n e m u s t

n o t b e r u n h i g h e r

t h a n t h i s l e v e l

M i n i m i z e T h i s

e n s i o n

D i m

Unit Piping

Gas Piping

See the “Installation” section of the gas-fired furnace installation manual, Bulletin No. IM684 or IM685.

Supply Water

City water must be piped into the service section of the unit. Install a manual shutoff valve to facilitate service of the unit. Provisions have been made to pipe through the floor of the service section within the curb. If the unit will be exposed to low outdoor air conditions, care must be taken to prevent freeze damage to this piping.

The service section has an optional heater to minimize freeze problems during cold weather. Verify that this heater functions before filling the unit. A sump heater option is also offered that includes heat tape on the pressure side of the float controlled fill valve, plus an extra 8 feet of heat tape to protect field connections inside the service compartment.

If the unit is mounted on post and rail structure, pipe will be exposed to outdoor conditions and will need to be heat taped or drained manually during the winter season.

26 McQuay IM 791-2

Mechanical Installation

Drain Water

A drain and bleed off connection is also located in the service section of the unit. Since this water will contain water treatment chemicals, local codes may require connection to the sanitary sewer. The freeze warning for supply water also applies to drain water piping.

Figure 26: Unit Piping Knockout Locations

Discharge

Air

Opening

7.87

6.88

9.26

DETAIL A

SCALE 1 : 9

4.75

2.25

6.75

4.75

Note: Make sure that a service compartment heater and

especially a sump heater or some type of freeze protection have been provided if freezing conditions are expected.

Walk-in

Vestibule

CONTROL WIRING .88" KNOCKOUT (3)

C ondensing

SUPPLY WATER

3.0" KNOCKOUT (.75" COPPER CONN ECTION)

Unit

7.87

26.50

DETAIL B

SCALE 1 : 9

21.50

3.0" KNOCKOUT (2)

Water Treatment

WARNING

Failure to maintain and continually provide water treatment will result in severe equipment damage and may create biologically hazardous conditions.

Water treatment, whether ordered as an option on the unit or purchased separately, must be properly installed and started before starting the unit. Failure to do so will result in scale build up on the condenser tubes with a resulting loss in heat rejection capacity. In severe cases, it may become impossible to operate the compressors. In addition, untreated cooling tower water can be a source for airborne disease.

Proper water treatment must include the following minimum features:

• Bleed Off

• Scale and corrosion inhibitor chemical treatment

• Biocide chemical treatment

See Catalog 219 for information on the optional McQuay supplied water treatment systems.

POWER WIRES

72.00

(REFERENCE)

DRAIN WATER

3.0" KNOCKOUT (2.0" PVC C ONNEC TION)

Hot Water Coil Piping

Hot water coils either are provided without valves for field piping or are piped with three-way valves and actuator motors. Note: If the unit is equipped with an iron valve, connecting to a copper piping system will likely cause galvanic corrosion to occur and the valve will not last. All coils have vents and drains factory installed.

Hot water coils are not normally recommended for use with entering air temperatures below 40°F (4°C). No control system can guarantee a 100% safeguard against coil freeze-up. Glycol solutions or brines are the only freeze-safe media for operation of water coils at low entering air temperature conditions.

When no factory piping or valve is included, the coil connections are 2-1/8" copper (two supply and two return). With the factory piping and valve package, field piping connections are the same NPT size as the valve with female threading (see Figure 27, page 28).

Refer to the certified drawings for the recommended piping entrance locations. All piping penetrations must be sealed to prevent air and water leakage.

Note: The valve actuator spring returns to a stem down

position upon power failure. This allows full flow through the coil.

McQuay IM 791-2 27

Mechanical Installation

CAUTION

Coil freeze possible. Possible equipment damage. Carefully read and follow instructions for mixing antifreeze solution. Some products will have higher freezing points in their natural state than when mixed with water. The freezing of coils is not the responsibility of McQuay International.

Figure 27: Hot Water Valve Package

R e t u r n

Figure 28: Hot Water Heat Section (Factory Valve/Piping)

B y p a s s

S u p p l y

Refer to the certified drawings for the recommended piping entrance locations. All piping penetrations must be sealed to prevent air and water leakage.

Note: The valve actuator spring returns to a stem up position

upon power failure. This allows full flow through the coil.

Steam Piping Recommendations

1 Be certain that adequate piping flexibility is provided.

Stresses resulting from expansion of closely coupled piping and coil arrangement can cause serious damage.

2 Do not reduce pipe size at the coil return connection. Carry

return connection size through the dirt pocket, making the reduction at the branch leading to the trap.

3 Install vacuum breakers on all applications to prevent

retaining condensate in the coil. Generally, connect the vacuum breaker between the coil inlet and the return main. However, if the system has a flooded return main, the vacuum breaker should be open to the atmosphere and the trap design should allow venting of large quantities of air.

4 Do not drain steam mains or takeoffs through coils. Drain

mains ahead of coils through a steam trap to the return line.

5 Do not attempt to lift condensate. 6 Pitch all supply and return steam piping down a minimum

of 1" (25 mm) per 10 feet (3 m) of direction of flow.

Steam Coil Piping

Steam coils either are provided without valves for field piping, or are piped with two-way valves and actuator motors.

The steam coil is pitched at 1/8" (3 mm) per foot (305 mm) to provide positive condensate removal. When no factory piping or valve is included, the coil connections are 2.5" male NPT iron pipe.

With the factory piping and valve package, the field supply connection is the same NPT size as the valve with female threading (see Figure 30, page 29).

Steam Trap Recommendations

1 Size traps in accordance with manufacturers'

recommendations. Be certain that the required pressure differential will always be available. Do not undersize.

2 Float and thermostatic or bucket traps are recommended for

low pressure steam. Use bucket traps on systems with onoff control only.

3 Locate traps at least 12" (305 mm) below the coil return

connection.

4 Always install strainers as closely as possible to the inlet

side of the trap.

5 A single tap may generally be used for coils piped in

parallel, but an individual trap for each coil is preferred.

Steam Coil Freeze Conditions

If the air entering the steam coil is below 35°F (2°C), note the following recommendations:

1 1.5 psi (34.5 kPa) steam must be supplied to coils at all

times.

2 Do not use modulating valves. Control should be by means

of face and bypass dampers.

3 As additional protection against freeze-up, the tap should

be installed sufficiently far below the coil to provide an adequate hydrostatic head to provide removal of condensate during an interruption on the steam pressure. Estimate 3 ft. (914 mm) for each 1 psi (7 kPa) of trap differential required.

28 McQuay IM 791-2

Mechanical Installation

4 If the unit is to be operated in environments with possible

freezing temperatures, an optional freezestat is recommended. See Freeze Protection‚ page 68 for additional information.

Figure 29: Valve Assembly

S t e m C l i p

S t e m

S e t s c r e w s

Figure 30: Steam Valve Package

Condensate

Figure 31: Steam Heat Section (Factory Valve/Piping)

McQuay IM 791-2 29

Mechanical Installation

Damper Assemblies

The optional damper assemblies described in this section are provided with manually adjustable linkages, or may be shipped with factory installed actuators and linkages.

Economizer Dampers

Outside air intake is provided on both sides of the unit, and the return air path is at the center of the damper set. As the single actuator modulates the outside air dampers open, the return air dampers close. Exhaust air exits the unit through the gravity relief dampers provided at the end of the economizer section.

The outside air return air damper assembly (economizer) comes with manually adjustable linkage. This adjustable linkage can also be used for connection of a damper operator.

The damper is set so that the crankarm moves through a 90degree angle to bring the economizer dampers from full open to full close. Mechanical stops have been placed in the crankarm mounting bracket. Do not remove stops. If the crankarm is driven past the stops, damage to the linkage or damper will result. The unit will ship with a shipping bolt securing the linkage crankarm. Remove shipping bolt before use.

Figure 32: Damper Adjustment

O u t s i d e

O p t i o n a l R e t u r n A i r F a n

A i r

E c o n o m i z e r

S h a f t . 5 0 0 D i a .

x 1 . 5 0 L o n g

O A

O p e n

9 0 °

S t r o k e

. 7 5

. 2 5

3 . 0 0

O A

C l o s e d

Note: For good airflow control, adjust linkages so damper

blades do not open beyond 70 degrees. Opening a damper blade beyond 70 degrees has little effect on its airflow. Do not “overclose” low leak damper blades. The edge seal should just lightly contact the adjoining blade. The blades will lock up if they are closed so far the seal goes over center.

30 McQuay IM 791-2

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