McQuay MPS006B Installation Manual

Installation and Maintenance Manual IM 971-1

Maverick™ I Commercial Packaged Rooftop Systems

Heating & Cooling

Models MPS006B - MPS012B

6 to 12 Tons

R-410A Refrigerant

Group: Applied Air Systems Part Number: IM 971-1 Date: July 2010

Contents

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

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Checking Product Received. . . . . . . . . . . . . . . . . 3

Safety Information . . . . . . . . . . . . . . . . . . . . 3

Major Components. . . . . . . . . . . . . . . . . . . . . . . . 3

Mechanical Installation . . . . . . . . . . . . . . . . . . . . . . 4

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Pre-Installation Check-Points . . . . . . . . . . . . . 4

Location Considerations . . . . . . . . . . . . . . . . . 4

Outside Installation . . . . . . . . . . . . . . . . . . . . . 5

Attaching Exhaust and Combustion Air Inlet

Hoods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Cover Panel Installation/Conversion

Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Filter Replacement . . . . . . . . . . . . . . . . . . . . . 6

Clearances . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Rooftop Installation . . . . . . . . . . . . . . . . . . . . . 6

Ductwork. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Return Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Gas Supply, Condensate Drain. . . . . . . . . . . . 8

Adjusting or Checking Furnace Input . . . . . . . 9

Condensate Drain. . . . . . . . . . . . . . . . . . . . . 10

Electrical Installation . . . . . . . . . . . . . . . . . . . . . . 11

Wiring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Power Supply . . . . . . . . . . . . . . . . . . . . . . . . 11

Hook-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Internal Wiring. . . . . . . . . . . . . . . . . . . . . . . . 12

208 Volt Applications. . . . . . . . . . . . . . . . . . . 12

Customer Supplied Thermostat . . . . . . . . . . 12

Optional Factory Supplied Thermostat . . . . . 13

Wiring Diagrams. . . . . . . . . . . . . . . . . . . . . . . . . 14

Physical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Unit Capacity and Physical Data . . . . . . . . . . . . 26

Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Compressor and Condenser Motor . . . . . . . . . . 28

MCA and MCOP . . . . . . . . . . . . . . . . . . . . . . . . 29

Auxiliary Heater Data . . . . . . . . . . . . . . . . . . . . . 30

Dimensional Data . . . . . . . . . . . . . . . . . . . . . . . . . 34

Unit Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . 34

Duct Dimensions . . . . . . . . . . . . . . . . . . . . . . . . 35

Curb Dimensions. . . . . . . . . . . . . . . . . . . . . . . . 35

Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . 36

Airflow Performance . . . . . . . . . . . . . . . . . . . . . 36

Accessories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Economizers: 6–12.5 Tons [21.1–44 kW] . . . . . 42

Economizers: 6–12.5 Tons [21.1–44 kW]

Horizontal Duct Installation . . . . . . . . . . . . . . . . 43

Fresh Air Dampers and Power Exhaust . . . . . . 44

Power Exhaust Kit For Economizers:

6–12 Tons [21.1–70.3 Kw] . . . . . . . . . . . . . . 44

Fresh Air Damper Kit for 6–12.5 Ton

[21.1–44.0 Kw] Units . . . . . . . . . . . . . . . . . . 46

Roofcurbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Roofcurbs (Full Perimeter): 6–12.5 Tons

[21.1–44.0 kW] . . . . . . . . . . . . . . . . . . . . . . . 47

Controls and Operation . . . . . . . . . . . . . . . . . . . . 48

Furnace Section Controls and Ignition System . 48

Normal Furnace Operating Sequence . . . . . 48

Operating Instructions . . . . . . . . . . . . . . . . . 49

Burners. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Manual Reset Over-Temperature Control . . 50

Pressure Switch . . . . . . . . . . . . . . . . . . . . . . 50

Limit Control . . . . . . . . . . . . . . . . . . . . . . . . . 50

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Advise The Customer. . . . . . . . . . . . . . . . . . 51

Unit Maintenance. . . . . . . . . . . . . . . . . . . . . . . . 51

Furnace Section . . . . . . . . . . . . . . . . . . . . . . 51

Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Cooling Section Maintenance . . . . . . . . . . . 52

System Charging Charts . . . . . . . . . . . . . . . . . . 53

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Cooling Troubleshooting Chart . . . . . . . . . . . . . 58

Furnace Troubleshooting Guide . . . . . . . . . . . . 59

Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Replacement Parts . . . . . . . . . . . . . . . . . . . . . . 61

Introduction

General

This manual contains the installation and operating instructions for your packaged rooftop system. There are some precautions that should be taken to derive maximum satisfaction from it. Improper installation can result in unsatisfactory operation or dangerous conditions.

Introduction

WARNING

Install this unit only in a location and position as specified in the Mechanical Installation section of these instructions. Provide adequate combustion and ventilation air to the unit space as specified in the venting section of these instructions.

Read this manual and any instructions packaged with separate equipment prior to installation. Give this manual to the owner and explain its provisions. The owner should retain this manual for future reference.

This product line does have an optional DDC controller. For operation and information on using and programming the MicroTech II unit controller, refer to the appropriate operation manual (see Table 1).

For a description of operation and information on using the keypad to view data and set parameters, refer to the appropriate program-specific operation manual (see Table 1).

Table 1: Operation, Installation and Maintenance Resources

Unit Manual

Rooftop unit control configuration DDC Unit Controller OM 1077

BACnet Communication Module IM 1000 LonWorks Communication Module IM 999

Operation manual bulletin number

Checking Product Received

Upon receiving the unit, inspect it for any damage from shipment. Claims for damage, either shipping or concealed, should be filed immediately with the shipping company. IMPORTANT: Check the unit model number, heating size, electrical characteristics, and accessories to determine if they are correct.

Safety Information

DANGER

WARNING

Combustion products must be discharged outdoors. Connect this unit to an approved vent system only, as specified in

Mechanical Installation section of these instructions.

WARNING

Use only with type of gas approved for this unit. Refer to the unit rating plate.

DANGER

Never test for gas leaks with an open flame. It can cause an explosion or fire resulting in property damage, personal injury or death. Use a commercially available soap solution made specifically for the detection of leaks to check all connections, as specified in the Mechanical Installation section of these instructions.

WARNING

Always install unit to operate within the unit's intended temperature-rise range with a duct system which has an external static pressure within the allowable range, as specified in the Mechanical Installation section of these instructions. See also unit rating plate.

DANGER

Units are not design certified to be installed inside the structure. Doing so can cause inadequate unit performance as well as property damage and carbon monoxide poisoning resulting in personal injury or death.

The manufacturer’s warranty does not cover any damage or defect to the air conditioner caused by the attachment or use of any components, accessories or devices (other than those authorized by the manufacturer) into, onto, or in conjunction with the air conditioner. you should be aware that the use of unauthorized components, accessories or devices may adversely affect the operation of the air conditioner and may also endanger life and property. The manufacturer disclaims any responsibility for such loss or injury resulting from the use of such unauthorized components, accessories or devices.

WARNING

Provide adequate combustion and ventilation air to the unit space as specified in the combustion and ventilation air section of these instructions.

Major Components

The unit includes a hermetically-sealed refrigerating system consisting of a scroll compressor, condenser coil, evaporator coil with capillary tube assembly, circulation air blower, condenser fan, heat exchanger assembly, gas burner and control assembly, combustion air motor and fan, and all necessary internal electrical wiring. The unit’s cooling system is factory-evacuated, charged and performance tested. Refrigerant amount and type are indicated on rating plate.

The unit is available in 150,000, 225,000 and 252,000 BTUH heating input. Cooling capacity is 6.5, 7.5, 8.5, 10 and 12 nominal tons. Units are convertible from bottom supply and return to side supply and return by relocation of supply and return air cover panels. The units are weatherized for mounting outside of the building.

McQuay IM 971-1 3

Mechanical Installation

General

WARNING

When a unit is installed so that supply ducts carry air circulated by the unit to areas outside the space containing the unit, the return air shall also be handled by duct(s) sealed to the unit casing and terminating outside the space containing the unit.

Install this unit in accordance with The American National Standard Z223.1-latest edition manual entitled “National Fuel Gas Code,” and the requirements or codes of the local utility or other authority having jurisdiction.

Additional helpful publications available from the “National Fire Protection Association” are: sNFPA-90A - Installation of Air Conditioning and Ventilating Systems 1985 or latest edition. NFPA-90B - Warm Air Heating and Air Conditioning Systems 1984.

These publications are available from: National Fire Protection Association, Inc.

Batterymarch Park Quincy, MA 02269

Pre-Installation Check-Points

1 Before attempting any installation, carefully consider the

following points:

a Structural strength of supporting members (rooftop

installation)

b Clearances and provision fo r servi cing power supply

and wiring

c Gas supply and piping d Air duct connections and sizing e Drain facilities and connections f Location for minimum noise and vibration - away

from bedroom windows

Location Considerations

The metal parts of this unit may be subject to rust or deterioration in adverse environmental conditions. This oxidation could shorten the equipment’s useful life. Salt spray, fog or mist in seacoast areas, sulphur or chlorine from lawn watering systems, and various chemical contaminants from industries such as paper mills and petroleum refineries are especially corrosive.

If the unit is to be installed in an area where contaminants are likely to be a problem, give special attention to the equipment location and exposure.

1 Avoid having lawn sprinkler heads spray directly on the

unit cabinet.

2 In coastal areas, locate the unit on the side of the building

away from the waterfront.

3 Shielding by a fence or shrubs may give some protection. 4 Frequent washing of the cabinet, fan blade and coil with

fresh water will remove most of the salt or other contaminants that build up on the unit.

5 Regular cleaning and waxing of the cabinet with a good

automobile polish will provide some protection.

6 A good liquid cleaner may be used several times a year

to remove matter that will not wash off with water.

Several different types of protective coatings are offered in some areas. These coatings may provide some benefit, but the effectiveness of such coating materials cannot be verified by the equipment manufacturer.

The best protection is frequent cleaning, maintenance, and minimal exposure to contaminants.

WARNING

This unit may be used to heat the building or structure during construction if the following installation requirements are met. Installation must comply with all install ation instructions including:

• Proper vent installation

• Furnace operating under thermostatic control

• Return air duct sealed to the furnace

• Air filters in place

• Set furnace input rate and temperature rise per rating plate

marking

• Means of providing outdoor air required for combustion

• Return air temperature maintained between 55°F (13°C )

and 80°F (27°C)

• Installation of exhaust and combustion air inl e t hoods

completed

• Clean furnace, duct work and components upon

substantial completion of the construction process, and verify furnace operating conditions including ignition, input rate, temperature rise and venting, according to the instructions.

4 McQuay IM 971-1

Mechanical Installation

Outside Installation

DANGER

These units are designed certified for outdoor installation only. Installation inside any part of a structure can result in inadequate unit performance as well as property damage. Installation inside can also cause recirculation of flue products into the conditioned space resulting in personal injury or death.

(Typical outdoor slab installation is show n in Figure 1.)

1 Select a location where external water drainage cannot

collect around unit.

2 Provide a level slab sufficiently high enough above grade

to prevent surface water from entering the unit

3 Locate the unit to provide proper access for inspection

and servicing as shown in Figure 3, page 6.

4 Locate unit where operating sounds will not disturb

owner or neighbors.

Figure 1: Outside Slab Installation

8 Remove compressor shipping supports (if so equipped)

after installation.

Attaching Exhaust and Combustion Air Inlet Hoods

IMPORTANT: Do not operate this unit without the exhaust/ combustion air inlet hood properly installed. This hood is shipped in a carton in the blower compartment inside the unit and must be attached when the unit is installed. See Figure 34,

page 42.

To attach exhaust/combustion air inlet hood:

1 Remove screws securing blower access panel and

remove access panel. For location of blower access panel, see Figure 26, page 34 .

2 Remove exhaust/combustion air inlet hood from the

carton, located inside the blower compartment.

3 Attach blower access panel. 4 Attach the combustion air inlet/exhaust hood with

screws. Reference Figure 26, page 34 for proper location. Screws are in carton with the hood.

5 Vent the unit using the flue exhaust hood, as supplied

from the factory, without alteration or addition. The only exception is with factory approved additions. Consult your local utility or other authority having jurisdiction for accepted venting techniques.

Locate unit so roof runoff water does not pour directly on the unit. Provide gutter or other shielding at roof level.Do not locate unit in an area where excessive snow drifting may occur or accumulate.

6 Where snowfall is anticipated, the height of the unit

above the ground level must be considered. Mount unit high enough to be above anticipated maximum area snowfall and to allow combustion air to enter the combustion air inlet.

7 Select an area which will keep the areas of the vent, air

intake, and A/C condenser fins free and clear of obstructions such as weeds, shrubs, vines, snow, etc.Inform the user accordingly.

Cover Panel Installation/Conversion Procedure

Downflow To Horizontal

1 Remove the screws and covers from the outside of the

supply and return sections. See Figure 2.

2 Install the covers over the bottom supply and return

openings, painted side up, inserting the leading flange under the bracket provided. Place the back flange to top of the front bracket provided. See Figure 2.

3 Secure the return and supply cover to front bracket with

one (1) screw .

Figure 2: Cover Gasket Detail, Downflow to Horizontal

McQuay IM 971-1 5

Mechanical Installation

Filter Replacement

This unit is provided with 6 - 18” × 18” × 2” disposable filters. When replacing filters, ensure they are inserted fully to the back to prevent bypass.

Clearances

The following minimum clearances must be observed for proper unit performance and serviceability (also see Figure 3).

Table 2: Recommended Clearances

Recommended

Clearance

48” A- Fr ont 18” B - Condenser Coil 18” C - Duct Side 18” D - Evaporator End 60” E - Above

*Without Economizer. 48” With Economizer

Figure 3: Clearances

Location

Figure 4: Flat Rooftop Installation, With Attic or Drop Ceiling Distributing System

Rooftop Installation

1 Before locating the unit on the roof, make sure that the

roof structure is adequate to support the weight involved. (See Electrical & Physical Tables in this manual.) THIS

IS VERY IMPORTANT AND THE INSTALLER'S RESPONSIBILITY.

2 For rigging and roofcurb details, see Figure 5 through

Figure 7.

3 The location of the unit on the roof should be such as to

provide proper access for inspection and servicing.

IMPORTANT: If unit will not be put into service immediately, block off supply and return air openings to prevent excessive condensation.

Ductwork

The installing contractor should fabricate ductwork in accordance with local codes. Use industry manuals as a guide when sizing and designing the duct system. Contact Air Conditioning Contractors of America, 1513 16th St. N.W.,

Washington, D.C. 20036.

DANGER

Never connect return ductwork to any other heat producing device such as fireplace insert, stove, etc. Unauthorized use of such devices may result in fire, carbon monoxide poisoning, explosion, personal injury, property damage or death.

Place the unit as close to the conditioned space as possible allowing clearances as indicated. Run ducts as directly as possible to supply and return outlets. Use of non-flammable weatherproof flexible connectors on both supply and return connections at unit to reduce noise transmission is recommended.

6 McQuay IM 971-1

Mechanical Installation

On ductwork exposed to outside temperature and humidity, use a minimum of 2" of insulation and a vapor barrier. Distribution system in attic, furred space or crawl space should be insulated with at least 2" of insulation. 1/2" to 1" thick insulation is usually sufficient for ductwork inside the air conditioned space.

Provide balancing dampers for each branch duct in the supply system. Properly support ductwork from the structure.

IMPORTANT: In the event that the return air ducts must be run through an “unconfined” space containing other fuel burning equipment, it is imperative that the user be informed against future changes in construction which might change this to a “confined space.” Also, caution the user against any future installation of additional equipment (such as power ventilators), within the existing unconfined and/or confined space which might create a negative pressure within the vicinity of other solid, liquid, or gas fueled units.

Return Air

DANGER

Never allow products of combustion or the flue products to enter the return air ductwork, or the circulating air supply. All return ductwork must be adequately sealed and secured to the furnace with sheet metal screws and joints must be taped. All other duct joints must be secured with approved connections and sealed airtight. Failure to prevent products of combustion from being circulated into the living space can create potentially hazardous conditions, including carbon monoxide poisoning that could result in personal injury or death.

Figure 5: Rigging Detail

A074403

Capacity Tons [kW]

7.5-12.5 [26.4-44.0]

Corner Weights by Percentage

A B C D

33% 27% 17% 23%

Figure 6: Shipping Board Removal

Illustration

ST-A0744-03

[ ] Designates Metric Conversions

Figure 7: Roofcurb

Remove Shipping Boards Before Installing Unit

McQuay IM 971-1 7

Mechanical Installation

Gas Supply, Condensate Drain

Gas Connection

IMPORTANT: Connect this unit only to gas supplied by a commercial utility.

1 Install gas piping in accordance with local codes and

regulations of the local utility company. In the absence of local codes, the installation must conform to the specifications of the National Fuel Gas Code, ANSI Z223.1 - latest edition.

Note: The use of flexible gas connectors is not permitted.

Connect the gas line to the gas valve supplied with unit.

Routing can be through the gas pipe opening shown in

Figure 26, page 34 or through the base as shown in Figure 1 1, page 12.

3 Size the gas line to the furnace adequate enough to

prevent undue pressure drop and never less than 1/2".

4 Install a drip leg or sediment trap in the gas supply line

as close to the unit as possible.

5 Install an outside ground joint union to connect the gas

supply to the control assembly at the burner tray.

6 Gas valves have been factory installed. Install a manual

gas valve where local codes specify a shut-off valve outside the unit casing (Figure 8).

7 Make sure piping is tight. A pipe compound resistant

to the action of liquefied petroleum gases must be used at all threaded pipe connections.

Figure 8: Suggested Gas Piping

IMPORTANT: Disconnect the furnace and its individual shutoff valve from the gas supply piping during any pressure testing of that system at test pressures in excess of 1/2 pound per square inch gauge or isolate the system from the gas supply piping system by closing its individual manual shutoff valve during any pressure testing of this gas supply system at

pressures equal to or less than 1/2 PSIG.

DANGER

Never test for gas leaks with an open flame. It can cause an explosion or fire resulting in property damage, personal injury or death. Use a commercially available soap solution made specifically for the detection of leaks to check all connections as specified in the “Mechanical Installation” section of these instructions.

IMPORTANT: Check the rating plate to make certain the unit is equipped to burn the type of gas supplied. Care should be taken after installation of th is equipment that the gas control valve not be subjected to high gas supply line pressure.In making gas connections, avoid strains as they may cause noise and damage the controls. A backup wrench is required to be

used on the valve to avoid damage.

Table 3: Gas Pipe Capacity Table (Cu. Ft./Hr.)

Nominal Iron Pipe Size

1/2” 132 92 73 63 56 50 46 43 3/4” 278 190 152 130 115 105 96 90 1” 520 350 285 245 215 195 180 170 1-1/4” 1,050 730 590 500 440 400 370 350 1-1/2” 1,600 1,100 890 760 670 610 560 530

10 20 30 40 50 60 70 80

Equivalent Length of Pipe, Feet

IMPORTANT: Any additions, changes or conversions

required for the furnace to satisfactorily meet the application should be made by a qualified installer, service agency or the gas supplier, using factoryspecified or approved parts. In the commonwealth of Massachusetts, installation must be performed by a licensed plumber or gas fitter for appropriate fuel.

The capacities of gas pipe of different diameters and lengths in cu.ft. per hr. with pressure drop of 0.3 in. and specific gravity of 0.60 (natural gas) are shown in Table 1.

After determining the pipe length, select the pipe size which will provide the minimum cubic feet per hour required for the gas input rating of the furnace. By formula:

Cu. Ft. per Hr. Required =

Gas Input of Furnace (BTU/Hr)

Heating Value of Gas (BTU/Ft3)

The gas input of the furnace is marked on the furnace rating

plate. The heating value of the gas (BTU/Ft

) may be determined by consulting the local natural gas utility or the LP gas supplier.

8 McQuay IM 971-1

Mechanical Installation

LP Conversion

Use a properly calibrated manometer gauge for accurate gas pressure readings.

DANGER

Only small variations in the gas flow should be made by means of the pressure regulator adjustment. Furnaces

This unit is equipped at the factory for use with natural gas only. Conversion to LP gas requires a special kit supplied by the distributor or manufacturer. Mailing addresses are listed on the furnace rating plate, parts list and warranty. Failure to use the proper conversion kit can cause fire, carbon monoxide poisoning, explosion, personal injury, property damage, or death.

functioning on LP gas must be set by means of the tank or branch supply regulators. The furnace manifold pressure should be set at 10" W.C. at the gas control valve.

To adjust the pressure regulator, remove the regulator cap and turn the adjustment screw clockwise to increase pressure or counterclockwise to decrease pressure. Then replace the

regulator cap securely.

Convert the unit to use liquefied petroleum (LP) gas by replacing with the gas valve supplied in the conversion kit.

Any necessary major changes in the gas flow rate should be made by changing the size of the burner orifices. To change

The LP gas valve maintains the proper manifold pressure for LP gas. The correct burner LP orifices are included in the kit.

IMPORTANT: To remove the natural gas valve, remove the four screws securing the manifold pipe to the burner tray. Remove the manifold pipe with gas valve attached.

Note: Order the correct LP conversion kit from the furnace

manufacturer. See Conversion Kit Index shipped with unit for proper LP kit number. Furnace conversion to LP gas must be performed by a qualified technician.

orifice spuds, shut off the manual main gas valve and remove the gas manifold.

For elevations up to 2,000 feet, rating plate input ratings apply. For high altitudes (elevations over 2,000 ft.), contact McQuay Parts. see conversion kit index 92-21519-XX for derating and orifice spud sizes.

Check of input is important to prevent over-firing of the furnace beyond its design-rated input. NEVER SET INPUT ABOVE THAT SHOWN ON THE RATING PLATE. Use the

Adjusting or Checking Furnace Input

Gas Type Line pressure (in wc) Manifold Pressure

Natural Gas 5 - 10.5 3.5

LP Gas 11-13 10

following table or formula to determine input rate.

Cu. Ft./Hr. Required =

Heating Value of Gas (BTU/CuFt) x 3600

Time in Seconds for 1 Cu. Ft. of Gas

Supply and manifold pressure taps are located on the gas valve body 1/8" N.P.T. and on the manifold.

Table 4: Meter Time In Minutes And Seconds For Normal Input Rating Of Furnaces Using Natural Or Lp Gas

Input

Btu/hr

40,000

60,000

80,000

100,000

Meter Size

Cu. Ft.

One

Ten

One

Ten

One

Ten

One

Ten

900 1000 1040 1100 2500

Min. Sec. Min. Sec. Min. Sec. Min. Sec. Min. Sec.

13

0 9

0 6

0 5

21 30

0 41 45

33 24

Table 5: LP Gas Pipe Capacity (Cubic feet per hour)

Nominal Iron Pipe

Size, Inches

1/2 275 189 152 129 114 103 96 89 83 78 3/4 567 393 315 267 237 217 196 182 173 162

1 1,071 732 590 504 448 409 378 346 322 307 1-1/4 2,205 1,496 1,212 1039 913 834 771 724 677 630 1-1/2 3,307 2,299 1,858 1,559 1,417 1,275 1,181 1,086 1,023 976

2 6,221 4,331 3,465 2,992 2,646 2,394 2,205 2,047 1,921 1,811

10 20 30 40 50 60 70 80 90 100

Heating Value Of Gas Btu Per Cu. Ft.

15

10

0 7

0 6

0 0

0 10 324

45 30

0

15

0 7

0 6

34 36

47 48

38 15

Length of Pipe, Feet

16

0 8

0 6

39 30

6 0

50 15

40 36

45 30

53 45

Start the furnace and measure the time required to burn one cubic foot of gas. Prior to checking the furnace input, make certain that all other gas units are shut off, with the exception of pilot burners. Time the meter with only the furnace in operation.

IMPORTANT NOTE FOR ALTITUDES ABOVE 2,000 FEET (610 METERS): The main burner orifices in your

furnace and in these kits are sized for the nameplate input and intended for installations at elevations up to 2,000 feet in the USA or Canada, or for elevations of 2,000 - 4,500 feet (610 -

McQuay IM 971-1 9

Mechanical Installation

1,373 meters) in Canada if the unit has been derated at the factory. For elevations above 2,000 feet (610 meters) IN THE USA ONLY (see ANSIZ223.1), the burner orifices must be sized to reduce the input 4% for each 1,000 feet (305 meters) above sea level.

NOTICE: Derating of the heating input for high altitude in the field is unlawful in Canada (refer to CAN/CGA 2.17). Units installed in altitudes greater than 2,000 feet (610 meters) must be shipped from the factory or from a factory authorized conversion station with the heating input derated by 10% so as to operate properly in altitudes from 2,000 - 4,500 feet (610 1,373 meters).

Condensate Drain

The condensate drain connection of the evaporator is threaded 1" nominal iron pipe. IMPORTANT: Install a condensate trap to ensure proper condensate drainage. See Figure 9.

Figure 9: Condensate Drain

10 McQuay IM 971-1

Electrical Installation

Wiring

Power Supply

DANGER

Power supply to the unit must be disconnected before making field connections. To avoid electrical shock, personal injury or death, be sure to rigorously adhere to field wiring procedures regarding proper lockout and tagout of components.

1 All wiring should be made in accordance with the

National Electrical Code. Consult the local power company to determine the availability of sufficient power to operate the unit. Check the voltage at power supply to make sure it corresponds to the unit's RATED VOLTAGE REQUIREMENT. Install a branch circuit disconnect near the rooftop, in accordance with the N.E.C., C.E.C. or local codes.

2 It is important that proper electrical power is available at

the unit. Voltage should not vary more than 10% from that stamped on the unit nameplate. On three phase units, phases must be balanced within 3%.

3 For branch circuit wiring (main power supply to unit

disconnect), the minimum wire size for the length of run can be determined fromTable 6 using the circuit ampacity found on the unit rating plate.

4 For through the base wiring entry reference Figure 18.

All fittings and conduit are field supplied for this application. Reference the chart with Figure 26, page 34

for proper hole and conduit size.

Table 6: Minimum Wire Sizes

Unit

MCA

20 10 8 6 4 4 4 25 10 8 6 4 4 3 30 8 6 4 4 3 2 35 8 6 4 3 2 1 40 8 6 4 3 2 1 45 8 4 3 2 1 1/0 50 6 4 3 2 1 1/0 60 6 4 2 1 1/0 2/0 70 4 3 2 1/0 2/0 3/0 80 4 3 1 1/0 2/0 3/0 90 3 2 1/0 2/0 3/0 4/0

100 3 2 1/0 2/0 3/0 4/0

110 2 1 2/0 3/0 4/0 250

125 1 1 2/0 3/0 4/0 25

Note:

50 10 0 150 200 250 300

Supply Wire Length in Feet

For branch circuit wiring (main power supply to unit

disconnect), the minimum wire size for the length of run can be determined from this table using the circuit ampacity found on the unit rating plate. From the unit disconnect to unit, the smallest wire size allowable in

Table 6 may be used, as the disconnect must be in sight

of the unit.

2 Wire size based on 75°C rated wire insulation for 1%

voltage drop.

3 For more than 3 conductors in a raceway or cable, see the

N.E.C. (C.E.C. in Canada) for derating the ampacity of each conductor.

IMPORTANT: This unit is approved for use with copper conductors only connected to unit contactor.

Warranty will be voided if aluminum wire is connected to unit contactor.

Figure 10: Recommended Branch Circuit Disconnect Location

Disconnect

McQuay IM 971-1 11

Electrical Installation

Figure 1 1: Base Entry Locations

WIRE FROM ZONE THERMOSTAT

TO BE ROUTED BEHIND SHIELD

INTEGRATED FURNACE

CONTROL LOW VOLTAGE

POWER WIRES

FROM DISCONNECT

TO CONTACTOR

AS SHOWN.

AND CONNECTED TO

TERMINAL STRIP

MAIN GAS VALVE

EXTERNAL PIPING SUPPLIED BY OTHERS

EXTERNAL GAS VALVE

CONDUIT NUT

BOTTOM GAS ENTRY

POWER WIRES

TO DISCONNECT

WIRE FROM

ZONE THERMOSTAT

TO BE ROUTED BEHIND

SHIELD AS SHOWN.

SIZED PER CHART

MIN. CIRCUIT AMPACITY

STRAIGHT CONDUIT

CUT HOLE

WIRE SIZE FROM

FITTING SIZED

PER CHART

CONDUIT FROM

POWER SUPPLY

SIZED PER CHART

CONTROL VOLTAGE KNOCK-OUT

WIRE FROM ZONE THERMOSTAT

STRAIGHT CONDUIT FITTING

CONDUIT FROM ZONE THERMOSTAT

Table 7: Recommended Wire Sizes

Wire Size, AWG 14 12 10 8 6 4 3 2 1 0 00 000

Conduit Size

Hole Size

Hook-Up

To wire unit, refer to the following hook-up diagram. Refer to

Figure 11, page12 and Figure 26, page 34 for location of

wiring entrances. Wiring to be done in the field between the unit and devices not attached to the unit, or between separate devices which are field installed and located, shall conform

1/2” 1/2” 1/2” 3/4” 1” 1” 1-1/4” 1-1/4” 1-1/2” 1-1/2” 2” 2” 7/8” 7/8” 7/8” 1-31/32” 1-23/64” 1-23/64” 1-23/32” 1-23/32” 1-31/32” 1-31/32” 2-15/32” 2-15/32”

Customer Supplied Thermostat

The customer supplied room thermostat must be compatible with the spark ignition control on the unit. Generally, all thermostats that are not of the “current robbing” type are compatible with the integrated furnace control. The low

voltage wiring should be sized as shown in Table 8. with the temperature limitation for Type T wire [63°F rise (35°C)] when installed in accordance with the manufacturer's instructions.

Internal Wiring

A diagram of the internal wiring of this unit is located on the inside of control access panel and in this manual. If any of the original wire as supplied with the unit must be replaced, the wire gauge and insulation must be same as original wiring.

208 Volt Applications

Transformer is factory wired for 230 volts on 208/230 volt models and must be changed for 208 volt applications. See unit wiring diagram for 208 volt wiring.

Table 8: Field Wire Size for 24 Volt Thermostat

Solid Copper Wire, AWG

3.0

2.5

2.0

Thermostat

Load Amps

Note: (1) The total wire length is the distance from the furnace to the

thermostat and back to the furnace.

Note: DO NOT USE CONTROL WIRING SMALLER THAN NO. 18 AWG.

50 100 150 200 250 300

Length of Run -Feet (1)

10 10

Install the room thermostat in accordance with the instruction

sheet packed in the box with the thermostat.

See Figure 13, page 14 for an example of a typical customer

supplied wiring diagram.

12 McQuay IM 971-1

Electrical Installation

Optional Factory Supplied Thermostat

Figure 12: Optional Thermostat

The optional factory supplied, touch screen, commercial setback digital thermostat (Figure 12) uses microcomputer technology to provide precise time and temperature control. This thermostat offers the flexibility to design heating and cooling programs that fit building needs (Table 9). This

thermostat is adaptable to most residential 24 volt forced air multi-stage systems with electric or fossil fuel auxiliary and is the ultimate for comfort, convenience, and performance.

See Figure 14, page 14 for an optional factory supplied thermostat wiring diagram.

Table 9: Optional Factory Supplied Thermostat Specifications

Electrical Rating Single Stage:

Electrical Rating Staging:

Terminal Load:

Setpoint Range:

Anticipation, Heating:

Anticipation, Cooling:

Rated Differential Single Stage:

Rated Differential Staging:

Operating Ambient:

Operating Humidity

Shipping Temperature Range:

Dimensions (H x W x D):

mV to 30 V (ac), NEC Class II, 50/60 Hz or DC

20 to 30 V (ac), NEC Class II

1.5 A per terminal, 2.5 A max. combined 45° to 99°F (7° to 37°C) Adjustable Adjustable Heat 0.6°F, Cool 1.2°F

Heat 0.6°F, Cool 1.2°F 32° to +105°F (0° to +41°C) 90% non-condensing max.

-4° to 150°F (-20° to 65°C)

4.6” x 5.9” x 1.2”

Table 10: Thermostat Terminal Functions

Y2 2nd Stage Compressor Y Compressor Relay GFan Relay RC Power for Cooling RH Power for Heating C Common wire from secondary side of cooling (Optional). Required for

fault indication, continuous backlight operation or remote temperature

sensor operation L Malfunction indicator for systems with malfunction connection W/E Heat Relay/Emergency Heat Relay (Stage 1) W2 2nd Stage Heat (3rd Stage Heat in HP2) Blank Blank

- Common (DC) for wired remote temperature sensor S Frequency signal from remote temperature sensor + Power (DC) to remote temperature sensor

McQuay IM 971-1 13

Electrical Installation

Wiring Diagrams

Figure 13: Typical Customer Supplied Thermostat Wiring Diagram

Figure 14: Optional Factory Supplied 7-170 Thermostat Wiring Diagram

Orange

Yellow

Green

Red

Brown

W/E

Black

C Y1GW2W1R Y2

Terminal Block

1) On 3 to 5 ton units, a terminal block is not supplied. Use a wirenut to extend from the leads provided in the unit to the thermostat. W1, W2, and Y2 are optional depending upon the size and selected options of the unit. Colors shown above are typical for the MPS I.

2) For wiring with DDC control option, see OM 1077 for wiring instructions.

14 McQuay IM 971-1