York Gf9s Dh User Manual

INSTALLATION MANUAL

HIGH EFFICIENCY

EFFICIENCY

RATING

CERTIFIED

TUBULAR HEAT EXCHANGER SERIES

MODELS: GY9S*DH / GM9S*DH / GF9S*DH

(Single Stage Downflow/Horizontal)

40 - 120 MBH INPUT

ISO 9001

Certified Quality

Management System

(11.72 - 35.17 KW) INPUT

LIST OF SECTIONS

SAFETY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

DUCTWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

GAS PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

ELECTRICAL POWER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

TWINNING AND STAGING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

COMBUSTION AIR AND VENT SYSTEM . . . . . . . . . . . . . . . . . . . . .14

CONDENSATE PIPING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

SAFETY CONTROLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

START-UP AND ADJUSTMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . .31

WIRING DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

LIST OF FIGURES

Transition Kit Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Return Filter Grill and Return Duct Installation . . . . . . . . . . . . . . . . . . . 8

Typical Attic Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Typical Suspended Furnace / Crawl Space Installation . . . . . . . . . . . . 9

Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Downflow Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Horizontal Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Electrical Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Thermostat Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Accessory Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Typical Twinned Furnace Application . . . . . . . . . . . . . . . . . . . . . . . . 13

Single Stage Twinning Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . 14

Two-Stage Twinning Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . 14

Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Home Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Downflow/Horizontal Vent Assembly . . . . . . . . . . . . . . . . . . . . . . . . . 18

Termination Configuration - 1 Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Termination Configuration - 2 Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Termination Configuration - 2 Pipe Horizontal . . . . . . . . . . . . . . . . . . 18

Crawl Space Termination Configuration - 2Pipe . . . . . . . . . . . . . . . . 19

Double Horizontal Sealed Combustion Air and Vent Termination . . . 19

Double Vertical Sealed Combustion Air and Vent Termination . . . . . 19

Sealed Combustion Air Intake Connection and Vent Connection . . .19

Combustion Airflow Path Through The Furnace Casing to the Burner

Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Outside and Ambient Combustion Air . . . . . . . . . . . . . . . . . . . . . . . . .21

Attic Combustion Air Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Condensate Drain Internal Hose Routing . . . . . . . . . . . . . . . . . . . . . .22

Downflow Condensate Drain Hose Configuration . . . . . . . . . . . . . . .23

Horizontal Left Condensate Drain Hose Configuration . . . . . . . . . . . .24

Horizontal Left Condensate Drain Hose Configuration . . . . . . . . . . . .25

Horizontal Right Condensate Drain Hose Configuration

(Option 1 - Front of Casing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Horizontal Right Condensate Drain Hose Configuration

(Option 1 - Front of Casing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Horizontal Right Condensate Drain Hose Configuration

(Option 2 - Back of Casing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

Horizontal Right Condensate Drain Hose Configuration

(Option 2 - Back of Casing) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30

Pressure Switch Tubing Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Gas Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Reading Gas Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Furnace Control Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35

Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

LIST OF TABLES

Unit Clearances to Combustibles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Minimum Duct Sizing For Proper Airflow . . . . . . . . . . . . . . . . . . . . . . . 5

Round Duct Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Cabinet and Duct Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Recommended Filter Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Nominal Manifold Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Electrical and Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Maximum Equivalent Pipe Length . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Equivalent Length of Fittings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Elbow Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Combustion Air Intake and Vent Connection Size at Furnace

(All Models) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Estimated Free Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Free Area - Outdoor Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Unconfined Space Minimum Area in Square Inches . . . . . . . . . . . . .20

Condensate Drain Hose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Inlet Gas Pressure Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Nominal Manifold Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Blower Performance CFM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Filter Performance - Pressure Drop Inches W.C. and (kPa) . . . . . . . .37

SECTION I: SAFETY

This is a safety alert symbol. When you see this symbol on

labels or in manuals, be alert to the potential for personal

injury.

Improper installation may create a condition where the operation of

the product could cause personal injury or property damage.

Improper installation, adjustment, alteration, service or mainte-

nance can cause injury or property damage. Refer to this manual

for assistance or for additional information, consult a qualified con-

tractor, installer or service agency.

Understand and pay particular attention to the signal words DANGER,

WARNING, or CAUTION.

DANGER indicates an imminently hazardous situation, which, if not

avoided, will result in death or serious injury.

WARNING indicates a potentially hazardous situation, which, if not

avoided, could result in death or serious injury.

CAUTION indicates a potentially hazardous situation, which, if not

avoided may result in minor or moderate injury. It is also used to

alert against unsafe practices and hazards involving only property dam-

age.

This product must be installed in strict compliance with the installa-

tion instructions and any applicable local, state, and national codes

including, but not limited to building, electrical, and mechanical

codes.

268890-UIM-B-0607

INSPECTION

As soon as a unit is received, it should be inspected for possible dam-

age during transit. If damage is evident, the extent of the damage

should be noted on the carrier’s freight bill. A separate request for

inspection by the carrier’s agent should be made in writing. Also, before

installation the unit should be checked for screws or bolts, which may

have loosened in transit. There are no shipping or spacer brackets

which need to be removed.

The furnace area must not be used as a broom closet or for any

other storage purposes, as a fire hazard may be created. Never

store items such as the following on, near or in contact with the fur-

nace.

1. Spray or aerosol cans, rags, brooms, dust mops, vacuum

cleaners or other cleaning tools.

2. Soap powders, bleaches, waxes or other cleaning com-

pounds; plastic items or containers; gasoline, kerosene, ciga-

rette lighter fluid, dry cleaning fluids or other volatile fluid.

3. Paint thinners and other painting compounds.

FURNACE LOCATION AND CLEARANCES

The furnace shall be located using the following guidelines:

1. Where a minimum amount of air intake/vent piping and elbows will

be required.

4. Paper bags, boxes or other paper products

2. As centralized with the air distribution as possible.

Never operate the furnace with the blower door removed. To

do so could result in serious personal injury and/or equipment

damage.

3. Where adequate combustion air will be available (particularly

when the appliance is not using outdoor combustion air).

4. Where it will not interfere with proper air circulation in the confined

space.

FOR FURNACES INSTALLED IN THE COMMON-

WEALTH OF MASSACHUSETTS ONLY

5. Where the outdoor combustion air/vent terminal will not be blocked

or restricted. Refer to “COMBUSTION AIR / VENT CLEAR-

ANCES” located in SECTION VII of these instructions. These min-

imum clearances must be maintained in the installation.

For all side wall horizontally vented gas fueled equipment installed in

every dwelling, building or structure used in whole or in part for resi-

dential purposes, including those owned or operated by the Com-

monwealth and where the side wall exhaust vent termination is less

than seven (7) feet above finished grade in the area of the venting,

including but not limited to decks and porches, the following require-

ments shall be satisfied:

6. Where the unit will be installed in a level position with no more

than 1/4” (0.6 cm) slope side-to-side and front-to-back to provide

proper condensate drainage.

Installation in freezing temperatures:

1. Furnace shall be installed in an area where ventilation facilities

provide for safe limits of ambient temperature under normal oper-

ating conditions. Ambient temperatures must not fall below 32°F

(0°C) unless the condensate system is protected from freezing.

1. INSTALLATION OF CARBON MONOXIDE DETECTORS. At

the time of installation of the side wall horizontal vented gas

fueled equipment, the installing plumber or gasfitter shall

observe that a hard wired carbon monoxide detector with an

alarm and battery back-up is installed on the floor level where

the gas equipment is to be installed. In addition, the installing

plumber or gasfitter shall observe that a battery operated or

hard wired carbon monoxide detector with an alarm is installed

on each additional level of the dwelling, building or structure

served by the side wall horizontal vented gas fueled equipment.

It shall be the responsibility of the property owner to secure the

services of qualified licensed professionals for the installation of

hard wired carbon monoxide detectors

2. Do not allow return air temperature to be below 55º F (13° C) for

extended periods. To do so may cause condensation to occur in

the main heat exchanger, leading to premature heat exchanger

failure.

Improper installation in an ambient below 32ºF (0.0° C) could create

a hazard, resulting in damage, injury or death.

a. In the event that the side wall horizontally vented gas

fueled equipment is installed in a crawl space or an attic,

the hard wired carbon monoxide detector with alarm and

battery back-up may be installed on the next adjacent floor

level.

3. If this furnace is installed in any area where the ambient tempera-

ture may drop below 32° F (0° C), a UL listed self-regulated heat

tape must be installed on any condensate drain lines. It is required

that self regulating heat tape rated at 3 watts per foot be used.

This must be installed around the condensate drain lines in the

unconditioned space. Always install the heat tape per the manu-

facturer's instructions. Cover the self-regulating heat tape with

fiberglass, Armaflex or other heat resistant insulating material.

b. In the event that the requirements of this subdivision can

not be met at the time of completion of installation, the

owner shall have a period of thirty (30) days to comply with

the above requirements; provided, however, that during

said thirty (30) day period, a battery operated carbon mon-

oxide detector with an alarm shall be installed.

4. If this unit is installed in an unconditioned space and an extended

power failure occurs, there will be potential damage to the conden-

sate trap, drain lines and internal unit components. Following a

power failure situation, do not operate the unit until inspection and

repairs are performed.

2. APPROVED CARBON MONOXIDE DETECTORS. Each car-

bon monoxide detector as required in accordance with the

above provisions shall comply with NFPA 720 and be ANSI/UL

2034 listed and IAS certified.

Clearances for access:

Ample clearances should be provided to permit easy access to the unit.

The following minimum clearances are recommended:

3. SIGNAGE. A metal or plastic identification plate shall be perma-

nently mounted to the exterior of the building at a minimum

height of eight (8) feet above grade directly in line with the

exhaust vent terminal for the horizontally vented gas fueled

heating appliance or equipment. The sign shall read, in print

size no less than one-half (1/2) inch in size, "GAS VENT

DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUC-

TIONS".

1. Twenty-four (24) inches (61 cm) between the front of the furnace

and an adjacent wall or another appliance, when access is

required for servicing and cleaning.

2. Eighteen (18) inches (46 cm) at the side where access is required

for passage to the front when servicing or for inspection or

replacement of flue/vent connections.

4. INSPECTION. The state or local gas inspector of the side wall

horizontally vented gas fueled equipment shall not approve the

installation unless, upon inspection, the inspector observes car-

bon monoxide detectors and signage installed in accordance

with the provisions of 248 CMR 5.08(2)(a)1 through 4.

In all cases, accessibility clearances shall take precedence over clear-

ances for combustible materials where accessibility clearances are

greater.

Unitary Products Group

268890-UIM-B-0607

When the furnace is used in conjunction with a cooling coil, the coil

must be installed parallel with, or in the supply air side of the furnace to

avoid condensation in the primary heat exchanger. When a parallel flow

arrangement is used, dampers or other means used to control airflow

must be adequate to prevent chilled air from entering the furnace. If

manually operated, the damper must be equipped with means to pre-

vent the furnace or the air conditioner from operating unless the damper

is in full heat or cool position.

Downflow/Horizontal furnaces for installation on combustible floor-

ing only when installed on the accessory combustible floor base on

wood flooring only and shall not be installed directly on carpeting,

tile or other combustible material.

Check the rating plate and power supply to be sure that the electri-

cal characteristics match. All models use nominal 115 VAC, 1

Phase 60Hz power supply.

Furnace shall be installed so the electrical components are pro-

tected from water.

The duct system must be properly sized to obtain the correct airflow

for the furnace size that is being installed.

Refer to Table 7 and the furnace rating plate for the correct rise

range and static pressures

If the ducts are undersized, the result will be high duct static pres-

sures and/or high temperature rises which can result in a heat

exchanger OVERHEATING CONDITION. This condition can result

in premature heat exchanger failure, which can result in personal

injury, property damage, or death.

Installation in a residential garage:

1. A gas-fired furnace for installation in a residential garage must be

installed so the burner(s) and the ignition source are located not

less than 18 inches (46 cm) above the floor, and the furnace must

be located or protected to avoid physical damage by vehicles.

TABLE 1: Unit Clearances to Combustibles

Application

Top

Downflow

1 (2.5)

3 (7.6)

0 (0)

Horizontal

0 (0)

FLOOR BASE AND DUCTWORK INSTALLATION

Downflow Combustible Floor Base

In. (cm)

Front

3 (7.6)

0 (0)

Rear

Installations on combustible materials require the use a com-

bustible floor base shown in Figure 1.

Left Side

Right Side

Flue

0 (0)

1 (2.5)

0 (0)

The floor base must be secured to the floor. A supply air duct

plenum with 1" (2.54 cm) flange is installed through the

opening provided. The supply air duct is then secured to the

duct system with screws and sealed to prevent leaks. Do not

shoot screws through the flanges of the supply air duct into the top of

the combustible floor base. Install the furnace on the combustible floor

base so that the corners of the furnace are parallel with the corner

brackets of the floor base. Follow the instructions supplied with the

combustible floor base accessory.

0 (0)

1 (2.5)¹

Floor / Bottom

Closet

0 (0)

Yes

Alcove

Yes

Attic

Yes

Yes²

Line Contact

1. Combustible floor base or air conditioning coil required for use on combusti-

ble floor.

2. Line contact only permitted between lines formed by the intersection of the

rear panel (top in horizontal position) of the furnace jacket and building

joists, studs or framing.

This combustible floor base can be replaced with a matching cooling

coil, properly sealed to prevent leaks. Follow the instructions supplied

with the cooling coil cabinet for installing the cabinet to the duct connec-

tor. Refer to the installation instructions for additional information.

SECTION II: DUCTWORK

DUCTWORK GENERAL INFORMATION

When replacing an existing furnace, if the existing plenum is not the

same size as the new furnace then the existing plenum must be

removed and a new plenum installed that is the proper size for the new

furnace.

The duct system’s design and installation must:

1. Handle an air volume appropriate for the served space and within

the operating parameters of the furnace specifications.

Ductwork Installation

2. Be installed in accordance with standards of NFPA (National Fire

Protection Association) as outlined in NFPA pamphlets 90A and

90B (latest editions) or applicable national, provincial, or state, and

local fire and safety codes.

NOTE: When attaching duct flange, do not shoot the screw down into

the casing. Use the formed flange intended for duct flange attachment.

A proper Heat Loss/Gain Calculation should be done on all installations

for proper application of equipment. From this the ductwork sizing can

be calculated, ACCA Manual J and D and industry standards are help-

ful.

3. Create a closed duct system. For residential and Non-HUD Modu-

lar Home installations, when a furnace is installed so that the sup-

ply ducts carry air circulated by the furnace to areas outside the

space containing the furnace, the return air shall also be handled

by a duct(s) sealed to the furnace casing and terminating outside

the space containing the furnace.

The duct system is a very important part of the installation. If the duct

system is improperly sized the furnace will not operate properly.

The ducts attached to the furnace plenum, should be of sufficient size

so that the furnace plenum should be if sufficient size so that the fur-

nace operates at the specified external static pressure and within the air

temperature rise specified on the nameplate.

4. Complete a path for heated or cooled air to circulate through the

air conditioning and heating equipment and to and from the condi-

tioned space.

Table 2 is a guide for determining whether the rectangular duct system

that the furnace is being connected to be of sufficient size for proper fur-

nace operation.

The cooling coil must be installed in the supply air duct, down-

stream of the furnace. Cooled air may not be passed over the heat

exchanger.

Unitary Products Group

268890-UIM-B-0607

Use the Example below to help you in calculating the duct area to deter-

mine whether the ducts have sufficient area so that the furnace oper-

ates at the specified external static pressure and within the air

temperature rise specified on the nameplate.

2. The square inch area for 7 inch round ducts, 38.4 square inch x 2

= 76.8 square inches,

3. Then take the 192 square inch from the rectangular duct and add it

to the 76.8 square inch of round duct. The total square inch of duct

attached to the furnace supply plenum is 268.8 square inches.

This exceeds the recommended 216 square inch of duct.

The following are general duct sizing guidelines that may not serve to

requirements of every application.

In this example, the duct system attached to the plenum has a sufficient

area so that the furnace operates at the specified external static pres-

sure and within the air temperature rise specified on the nameplate.

Providing the return duct is properly sized as well.

Example: The furnace input is 80,000 BTUH, 1,200 CFM blower

requirement. The recommended duct area is 216 sq.in, there are two 8

x 12 rectangular ducts attached to the plenum and there are two 7 inch

round ducts attached to the furnace.

1. Take 8 x 12, which equals 96 square inch x 2 = 192 square inches

then go to round duct size located in Table 3.

TABLE 2: Minimum Duct Sizing For Proper Airflow

Return¹

In² (cm²)

Rectangular²

Round²

in. (cm)dia.

18 (45.7)

22 (55.8)

24 (60.9)

Supply³

In²(cm²)

Rectangular²

Round²

in. (cm)dia.

16 (40.6)

18 (45.7)

22 (55.8)

Input

Nominal Airflow

BTU/H(kW)

40,000 (11.7)

60,000 (17.6)

80,000 (23.4)

100,000 (29.3)

120,000 (35.2)

CFM(m³/min)

1,200 (34.0)

1,600 (45.3)

2,000 (56.6)

in. x in.(cm x cm)

280 (1806)

360 (2322)

440 (2839)

14 x 20 (35.6 x 90.8)

14 x 20 (35.6 x 50.8)

18 x 20 (45.7 x 50.8)

20 x 22 (50.8 x 55.8)

216 (1394)

280 (1806)

390 (2516)

12 x 18 (30.5 x 45.7)

14 x 20 (35.6 x 50.8)

16 x 22 (40.6 x 55.8)

NOTE: This chart does not replace proper duct sizing calculations or take into account static pressure drop for run length and fittings. Maintain proper temperature rise

and static pressures.

1. Maximum return air velocity in rigid duct @ 700 feet per minute (213 m/min).

2. Example return main trunk duct minimum dimensions.

3. Maximum supply air velocity in rigid duct @ 900 feet per minute (274m/min).

The transition duct must be the same dimensional size as the rectangu-

lar opening in the base of the furnace.

TABLE 3: Round Duct Size

Round Duct Size

Inches (cm)

Calculated Area For Each Round Duct Size

Sq.in (cm²)

19.6 (126)

28.2 (182)

38.4 (248)

50.2 (324)

63.6 (410)

78.5 (506)

95 (613)

DOWNFLOW

FURNACE

5 (13)

6 (15)

7 (18)

WARM AIR PLENUM

WITH 1” FLANGES

8 (20)

9 (23)

FIBERGLASS

INSULATION

10 (25)

11 (28)

12 (30)

13 (33)

14 (36)

113.1 (730)

132.7 (856)

153.9 (993)

FIBERGLASS TAPE

UNDER FLANGE

1. The Air Temperature Rise is determined by subtracting the Return

COMBUSTIBLE FLOOR

BASE ACCESSORY

Air Temperature Reading from the Supply Air Temperature Read-

ing.

2. The External Static Pressure is determined by adding the Supply

Duct Static Pressure reading to the Return Duct Static Pressure

reading.

FIGURE 1 : Combustible Floor Base Accessory

TABLES 2 AND 3 are to be used as a guide only to help the installer

determine if the duct sizes are large enough to obtain the proper air flow

(CFM) through the furnace. TABLES 2 and 3 ARE NOT to be used to

design ductwork for the building where the furnace is being installed.

There are several variables associated with proper duct sizing that are

not included in the tables. To properly design the ductwork for the build-

ing, Refer to the ASHRAE Fundamentals Handbook, Chapter on

“DUCT DESIGN” or a company that specializes in Residential and Mod-

ular Home duct designs.

The supply air temperature MUST NEVER exceed the Maximum

Supply Air Temperature, specified on the nameplate.

Operating the furnace above the maximum supply air temperature

will cause the heat exchanger to overheat, causing premature heat

exchanger failure. Improper duct sizing, dirty air filters, incorrect

manifold pressure, incorrect gas orifice and/or a faulty limit switch

can cause the furnace to operate above the maximum supply air

temperature. Refer to sections II, III, IX & X for additional informa-

tion on correcting the problem.

IMPORTANT: If the supply air duct is being connected to the furnace

without the use of an accessory duct connector, then a transition duct

must be installed with flanges or tabs that are securely attach and

sealed to the supply air duct and to the base of the furnace. The transi-

tion duct must have insulation between the transition duct and any com-

bustible material.

Unitary Products Group

268890-UIM-B-0607

Downflow Air Conditioning Coil Cabinet

Horizontal Models

The Cooling Coil Cabinet can be used in place of the combustible floor

base for downflow installations on combustible materials. The furnace

should be installed with the cooling coil cabinet specifically intended for

downflow applications. The cooling coil cabinet must be secured to the

floor. A supply air duct plenum is installed through the opening pro-

vided. The supply air duct is then secured to the duct system with

screws and sealed to prevent leaks. If a matching cooling coil is used, it

may be placed directly on the furnace outlet using the accessory transi-

tion kit and sealed to prevent leakage. The transition kit must be used to

secure the cooling coil cabinet to the furnace casing when installed in a

downflow configuration.

IMPORTANT: This furnace may be installed in a horizontal position on

either side as shown above. It must not be installed on its back.

Horizontal Installations With a Cooling Coil Cabinet

The furnace should be installed with the cooling coil cabinet specifically

intended for horizontal applications. If a matching cooling coil is used, it

may be placed directly on the supply air side of the furnace and sealed

to prevent leakage. A warm air duct plenum with 1" (2.54 cm) is

installed through the opening provided. The supply air duct system is

connected to the warm air plenum and sealed to prevent leaks.

These kits are required in downflow application when using G*F* series

coils. These kits are not required with MC/FC series coils, but please

ensurethat the coil and furnace are sucured and that there are noair

leaks.

This transition kit may be installed in one of two ways. The transition kit

may be installed and secured to either the furnace or the cooling coil

cabinet by the use of screws and then it must be sealed to prevent

leaks.

IMPORTANT: The furnace, the cooling coil cabinet, and all duct work

MUST BE SEALED as needed to prevent leaks, AND SECURED. Refer

to the assembly drawing in Figure 2.

Attach the supply plenum to the air conditioning coil cabinet outlet duct

flanges through the use of S cleat material when a metal plenum is

used. The use of an approved flexible duct connector is recommended

on all installations. The connection to the furnace, air conditioning coil

cabinet and the supply plenum should be sealed to prevent air leakage.

•

If the transition kit has been installed on the cooling coil cabinet it

must be secured to the cooling coil cabinet with screws. The sup-

ply air side of the furnace is then placed on the cooling coil cabi-

net and then sealed for leaks.

•

If the transition kit has been installed on the supply air side of the

furnace it must be secured to the furnace with screws. The fur-

nace and the transition kit are then placed on the cooling coil cab-

inet and then sealed for leaks.

The sheet metal plenum should be crosshatched to eliminate any pop-

ping of the sheet metal when the indoor fan is energized. The minimum

plenum height is 12" (30.5 cm). If the plenum is shorter than 12" (30.5

cm) the turbulent air flow may cause the limit controls not to operate as

designed, or the limit controls may not operate at all. Also the plastic

drain pan in the under the air conditioning coil can overheat and melt

Refer to the installation instructions supplied with the air conditioning

coil for additional information.

NOTE: Refer to instructions packed out with coil cabinet, for securing

and sealing to the furnace.

IMPORTANT: The furnace, transition kit, and the cooling coil cabinet

MUST BE SEALED as needed to prevent leaks, AND SECURED. Refer

to the assembly drawing in Figure 2.

Horizontal Installations Without a Cooling Coil Cabinet

IMPORTANT: On all installations without a coil, a removable access

panel is recommended in the outlet duct such that smoke or reflected

light would be observable inside the casing to indicate the presence of

leaks in the heat exchanger. This access cover shall be attached in

such a manner as to prevent leaks.

When installing this appliance, the furnace must be installed so as to

create a closed duct system, the supply duct system must be con-

nected to the furnace outlet and the supply duct system must terminate

outside the space containing the furnace. When replacing an existing

furnace, if the existing plenum is not the same size as the new furnace

then the existing plenum must be removed and a new plenum installed

that is the proper size for the new furnace.

AIRFLOW

Attach the supply plenum to the furnace outlet duct flanges through the

use of S cleat material when a metal plenum is used. The use of an

approved flexible duct connector is recommended on all installations.

This connection should be sealed to prevent air leakage. The sheet

metal should be crosshatched to eliminate any popping of the sheet

metal when the indoor fan is energized. On all installations without a

coil, a removable access panel is recommended in the outlet duct such

that smoke or reflected light would be observable inside the casing to

indicate the presence of leaks in the heat exchanger. This access cover

shall be attached in such a manner as to prevent leaks.

TRANSITION

KIT

DOWNFLOW

FURNACE

REFRIGERANT

LINES

AIRFLOW

COOLING

COIL

CABINET

DRAIN

CONNECTIONS

AIRFLOW

TRANSITION

KIT

AIRFLOW

FIGURE 2: Transition Kit Assembly

Unitary Products Group

268890-UIM-B-0607

T-STAT WIRING 7/8” K.O.

HORIZONTAL CONDENSATE

DRAIN OPENING 1-3/4”

HORIZONTAL CONDENSATE

DRAIN OPENING 1-3/4”

HORIZONTAL CONDENSATE

DRAIN OPENING 2”

HORIZONTAL

CONDENSATE

DRAIN OPENING 1-3/4”

JUNCTION BOX

HOLE 7/8”

JUNCTION BOX

HOLE 7/8”

GAS PIPE ENTRY 1-1/2”

GAS PIPE

ENTRY 1-1/2”

CONDENSATE DRAIN

HOLE 7/8”

SIDE PIPING HOLE 3-3/8”

CONDENSATE DRAIN

HOLE 7/8”

28-1/2

FRONT

LEFT SIDE

RIGHT SIDE

23-5/8

1-1/4

5/8

19-1/4

1-1/4

5/8

2-1/4

23-1/4

TOP IMAGE

RETURN END

BOTTOM IMAGE

SUPPLY END

FIGURE 3: Dimensions

TABLE 4: Cabinet and Duct Dimensions

Cabinet Dimension

BTUH (kW)

CFM

Cabinet

Size

Input/Output

A (in.)

A (cm)

B (in.)

B (cm)

33.7

41.3

50.2

59.1

C (in.)

C (cm)

30.5

38.1

47.0

55.9

D (in.)

1-3/4

2-1/8

2-1/2

D (cm)

4.44

5.40

6.35

40/37 (11.7/10.8)

60/56 (17.6/16.4)

80/75 (23.4/22.0)

100/95 (29.3/27.8)

120/112 (35.1/32.8)

1200 (34.0)

14-1/2

17-1/2

36.8

44.4

53.3

62.2

13-1/4

16-1/4

19-3/4

23-1/4

1200 (34.0)

1600 (45.3)

2000 (56.6)

18-1/2

24-1/2

RESIDENTIAL AND NON HUD MODULAR HOME

DOWNFLOW AND HORIZONTAL RETURN PLENUM

CONNECTION

The return duct system must be connected to the furnace inlet and the

return duct system must terminate outside the space containing the fur-

nace. When replacing an existing furnace, if the existing plenum is not

the same size as the new furnace then the existing plenum must be

removed and a new plenum installed that is the proper size for the new

furnace.

IMPORTANT: If an external mounted filter rack is being used see the

instructions provided with that accessory for proper hole cut size.

SECTION III: FILTERS

FILTER INSTALLATION

All applications require the use of a filter. Replacement filter size is

shown in Table 5.

TABLE 5: Recommended Filter Sizes

Attach the return plenum to the furnace inlet duct flanges. This is typi-

cally through the use of S cleat material when a metal plenum is used.

The use of an approved flexible duct connector is recommended on all

installations. The connection of the plenum to the furnace and all the

ducts connecting to the plenum must be sealed to prevent air leakage.

The sheet metal should be crosshatched to eliminate any popping of

the sheet metal when the indoor fan is energized.

CFM

Input / Output

BTU/H (kW)

Cabinet

Size

Top Return

Filter in(cm)

(m³/min)

1200 (34)

1600 (45)

2000 (57)

40 (11.7)

60 (17.8)

80 (23.4)

100 (29.3)

120 (35.1)

(2) 14 x 20 (36 x 51)

The duct system is a very important part of the installation. If the duct

system is improperly sized the furnace will not operate properly. The

ducts attached to the furnace must be of sufficient size so that the fur-

nace operates at the specified external static pressure and within the air

temperature rise specified on the nameplate.

NOTES:

1. Air velocity through throwaway type filters may not exceed 300 feet

per minute. All velocities over this require the use of high velocity fil-

ters.

Attic installations must meet all minimum clearances to combustibles

and have floor support with required service accessibility.

Unitary Products Group

268890-UIM-B-0607

Downflow Filters

HORIZONTAL APPLICATION

Downflow furnaces typically are installed with the filters located above

the furnace, extending into the return air plenum or duct. Any branch

duct (rectangular or round duct) attached to the plenum must attach to

the vertical plenum above the filter height.

Horizontal Filters

All filters and mounting provision must be field supplied. Filters(s) may

be located in the duct system external to the furnace or in a return filter

grille(s). Filters(s) may be located in the duct system using an external

duct filter box attached to the furnace plenum. Any branch duct (rectan-

gular or round duct) attached to the plenum must attach to the vertical

plenum above the filter height. The use of straps and / or supports is

required to support the weight of the external filter box.

Filters(s) may be located in the duct system external to the furnace

using an external duct filter box attached to the furnace plenum or at the

end of the duct in a return filter grille(s). The use of straps and / or sup-

ports is required to support the weight of the external filter box.

If the accessory electronic air cleaner is installed, be sure the air

cleaner is designed to accommodate the furnace CFM (cm/m) and the

air cleaner is installed so it does not obstruct the return airflow. Consid-

eration should be given when locating the air cleaner for maintenance

and temperatures should the indoor fan motor fail to operate. The use

of straps and / or supports is required to support the weight of the elec-

tronic air cleaner. It is recommended that the air cleaner not be located

within 12 inches (30.5 cm) from the top of the return air opening on the

furnace. Refer to the instructions supplied with the electronic air

cleaner.

An accessory filter rack is available.

ATTIC INSTALLATION

LINE CONTACT ONLY PERMISSIBLE

BETWEEN LINES FORMED BY THE

INTERSECTION OF FURNACE TOP

AND TWO SIDES AND BUILDING

JOISTS, STUDS OR FRAMING

COMBUSTION

AIR

FILTER RACK

GAS

PIPING

RETURN

AIR

SUPPLY

AIR

All loose accessories shipped with the furnace must be removed

from the blower compartment, prior to installation.

VENT PIPE

If pleated media air filters or any filter that has a large pressure drop is

installed in the return air duct system be sure that the pressure drop

caused by the air filter will not prevent the furnace from operating within

the rise range specified on the rating plate. If the furnace does not oper-

ate within the specified rise range then a larger air filter or an air filter

that has a lower pressure drop must be installed.

(maintain required

clearances to

combustible)

30” MIN.

WORK AREA

12” CLEARANCE

FOR SERVICE

FIGURE 5: Typical Attic Installation

This appliance is design certified for line contact when the furnace is

installed in the horizontal left or right position. The line contact is only

permissible between lines are formed by the intersection of the top and

two sides of the furnace and the building joists, studs or framing. This

line may be in contact with combustible material.

IMPORTANT: For easier filter access in a downflow configuration, a

removable access panel is recommended in the vertical run of the

return air plenum immediately above the furnace.

CLOSET

IMPORTANT: In either a horizontal left or right installation, a minimum

of 8" (20.3 cm) clearance is required beneath the furnace to allow for

the installation of the condensate trap and drain pipe. Refer to "CON-

DENSATE PIPING" section of this manual for more information.

COMBUSTION

AIR

RETURN

AIR

VENT

PIPE

AIR

FILTERS

When a furnace is installed in an attic or other insulated space,

keep all insulating materials at least 12 inches (30.5 cm) away from

furnace and burner combustion air openings.

ELECTRICAL

SUPPLY

GAS SUPPLY

(EITHER SIDE)

If this furnace is installed over a finished space, a condensate

safety pan must be installed.

FIGURE 4: Return Filter Grill and Return Duct Installation

SUSPENDED FURNACE / CRAWL SPACE

INSTALLATION

IMPORTANT: Air velocity through throwaway type filters must not

exceed 300 feet per minute (91 m/min). All velocities over this require

the use of high velocity filters. Refer to Table 19.

The furnace can be hung from floor hoists or installed on suitable blocks

or pad. Blocks or pad installations shall provide adequate height to

ensure the unit will not be subject to water damage. Units may also be

suspended from rafters or floor joists using rods, pipe angle supports or

straps. Angle supports should be placed at the supply air end and near

the blower deck. Do not support at return air end of unit. All four sus-

pension points must be level to ensure quite furnace operation. When

suspending the furnace use a secure a platform constructed of plywood

or other building material secured to the floor joists. Refer to Figure 6

for typical crawl space installation.

All installations must have a filter installed.

Unitary Products Group

268890-UIM-B-0607

EXTERNAL MANUAL

SHUTOFF VALVE

TO GAS

SUPPLY

TO GAS

SUPPLY

SUPPORT

BRACKET

ANGLE IRON

BRACKET

1” MAX. BETWEEN

ROD & FURNACE

6” MIN. BETWEEN

ROD & FURNACE

GROUNDED JOINT UNION

MAY BE INSTALLED

INSIDE OR OUTSIDE UNIT.

1” MAX. BETWEEN

ROD & FURNACE

DRIP

LEG

FIGURE 6: Typical Suspended Furnace / Crawl Space Installation

FIGURE 8: Downflow Gas Piping

MANUAL

SHUT-OFF

VALVE

In any application where temperatures below freezing are possible,

see “BELOW FREEZING LOCATIONS”.

DRIP

LEG

GAS

PIPE

GAS BURNERS

GAS VALVE

SECTION IV: GAS PIPING

GAS SAFETY

GAS

PIPE

MANUAL

SHUT-OFF VALVE

DRIP

LEG

An overpressure protection device, such as a pressure regulator,

must be installed in the gas piping system upstream of the furnace

and must act to limit the downstream pressure to the gas valve so it

does not exceed 0.5 PSI {14" w.c. (3.48 kPa)}. Pressures exceed-

ing 0.5 PSI {14” w.c. (3.48 kPa)} at the gas valve will cause damage

to the gas valve, resulting in a fire or explosion or cause damage to

the furnace or some of its components that will result in property

damage and loss of life.

FIGURE 9: Horizontal Gas Piping

IMPORTANT: An accessible manual shutoff valve must be installed

upstream of the furnace gas controls and within 6 feet (1.8 m) of the fur-

nace.

The furnace must be isolated from the gas supply piping system by

closing its individual external manual shutoff valve during any pressure

testing of the gas supply piping system at pressures equal to or less

than 1/2 psig (3.5 kPa).

OUTLET

PRESSURE

PORT

VENT PORT

INLET

OUTLET

Never apply a pipe wrench to the body of the gas valve when

installing piping. A wrench must be placed on the octagonal hub

located on the gas inlet side of the valve. Placing a wrench to the

body of the gas valve will damage the valve causing improper oper-

ation and/or the valve to leak.

WRENCH

BOSS

INLET

PRESSURE

PORT

MAIN REGULATOR

ADJUSTMENT

ON/OFF SWITCH

(Shown in ON position)

Gas piping may be connected from either side of the furnace using any

of the gas pipe entry knockouts on both sides of the furnace. Refer to

Figure 3 dimensions.

FIGURE 7: Gas Valve

IMPORTANT: Plan your gas supply before determining the correct gas

pipe entry. Use 90-degree service elbow(s), or short nipples and con-

ventional 90-degree elbow(s) to enter through the cabinet access holes.

GAS ORIFICE CONVERSION FOR PROPANE (LP)

This furnace is constructed at the factory for natural gas-fired operation,

but may be converted to operate on propane (LP) gas by using a fac-

tory-supplied LP conversion kit. Follow the instructions supplied with

the LP kit. Refer to Table 6 or the instructions in the propane (LP) con-

version kit for the proper gas orifice size.

GAS PIPING INSTALLATION

Properly sized wrought iron, approved flexible or steel pipe must be

used when making gas connections to the unit. If local codes allow the

use of a flexible gas appliance connection, always use a new listed con-

nector. Do not use a connector that has previously serviced another gas

appliance.

HIGH ALTITUDE GAS ORIFICE CONVERSION

This furnace is constructed at the factory for natural gas-fired operation

at 0 – 8,000 feet (0-m – 2,438 m) above sea level.

Some utility companies or local codes require pipe sizes larger than the

minimum sizes listed in these instructions and in the codes. The furnace

rating plate and the instructions in this section specify the type of gas

approved for this furnace - only use those approved gases. The instal-

lation of a drip leg and ground union is required. Refer to Figure 8.

The manifold pressure must be changed in order to manitain proper

and safe operation when the furnace is installed in a location where the

altitude is greater than 8,000 feet (2,438 m) above sea level. Refer to to

Table 6 for proper manifold pressure settings.

HIGH ALTITUDE PRESSURE SWITCH CONVERSION

For installation where the altitude is less than 8,000 feet (2,438 m), it is

not required that the pressure switch be changed. For altitudes above

8,000 feet (2,438 m), see Field Installed Accessories - High Altitude

pressure Switch.

Unitary Products Group

268890-UIM-B-0607

TABLE 6: Nominal Manifold Pressure

Manifold Pressures (in wc)

Altitude (feet)

Manifold Pressures (kpa)

Altitude (m)

0-7999

3.5

8000-8999

3.5

9000-9999

3.5

0-2437

0.87

0.80

2.44

2438-2742

0.87

2743-3048

0.87

800

850

29.8

31.7

3.5

0.87

900

3.5

33.5

0.87

950

3.5

3.3

35.4

0.87

0.81

1000

1050

1100

3.5

3.2

2.9

37.3

0.80

0.73

3.5

2.9

2.7

39.1

0.73

0.67

3.2

2.7

2.4

41.0

0.66

0.61

2500 (LP)

9.8

8.2

7.5

93.2 (LP)

2.03

1.86

PROPANE AND HIGH ALTITUDE CONVERSION KITS

It is very important to choose the correct kit and/or gas orifices for the altitude and the type of gas for which the furnace is being installed.

Only use natural gas in furnaces designed for natural gas. Only use propane (LP) gas for furnaces that have been properly converted to use pro-

pane (LP) gas. Do not use this furnace with butane gas.

Incorrect gas orifices or a furnace that has been improperly converted will create an extremely dangerous condition resulting in premature heat

exchanger failure, excessive sooting, high levels of carbon monoxide, personal injury, property damage, a fire hazard and/or death.

High altitude and propane (LP) conversions are required in order for the appliance to satisfactory meet the application.

An authorized distributor or dealer must make all gas conversions.

In Canada, a certified conversion station or other qualified agency, using factory specified and/or approved parts, must perform the conversion.

The installer must take every precaution to insure that the furnace has been converted to the proper gas orifice size when the furnace is installed.

Do not attempt to drill out any orifices to obtain the proper orifice size. Drilling out a gas orifice will cause misalignment of the burner flames,

causing premature heat exchanger burnout, high levels of carbon monoxide, excessive sooting, a fire hazard, personal injury, property damage

and/or death.

SECTION V: ELECTRICAL POWER

ELECTRICAL POWER CONNECTIONS

Field wiring to the unit must be grounded. Electric wires that are field

installed shall conform to the temperature limitation for 63°F (35°C) rise

Use copper conductors only.

wire when installed in accordance with instructions. Refer to Table 7 in

these instructions for specific furnace electrical data.

TABLE 7: Electrical and Performance Data

Input/Cabinet

Output

MBH

Nominal Airflow

Cabinet Width

Total Unit

AFUE

Air Temp. Rise

m³/min

CFM

MBH

40/A

In.

14-1/2

17-1/2

368

444

533

622

Amps

°F

°C

112

10.8

16.1

21.7

27.3

32.8

1200

1600

2000

35 - 65

19 - 36

60/B

34.0

45.3

56.6

80/B

80/C

100/C

120/D

24-1/2

Max. Outlet

Air Temp.

Operation

Weight

Max.

Min. Wire Size

Input/Cabinet

Blower

Blower Size

Over-current (awg) @ 75 ft.

Protect

One Way

MBH

40/A

°F

°C

1/2

3/4

Amps

7.0

In.

Lbs.

120

130

145

155

170

175

180

Kg.

165

73.9

11 x 8

27.9 x 20.3

54.5

59.0

65.9

70.5

77.3

79.5

81.8

60/B

7.0

80/B

7.0

80/C

10.2

12.7

11 x 10 27.9 x 25.4

11 x 10 25.4 x 25.4

11 x 11 27.9 x 27.9

100/C

120/D

Annual Fuel Utilization Efficiency (AFUE) numbers are determined in accordance with DOE Test procedures.

Wire size and over current protection must comply with the National Electrical Code (NFPA-70-latest edition) and all local codes.

The furnace shall be installed so that the electrical components are protected from water.

NOTES:

1. For altitudes above 2000 ft. (609 m) reduce capacity 4% for each 1000 ft. above sea level.

2. Wire size based on copper conductors, 140° F (60°C), 3% voltage drop.

3. Continuous return air temperature must not be below 55°F (12.8° C).

Unitary Products Group

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SUPPLY VOLTAGE CONNECTIONS

IMPORTANT: The power connection leads and wiring box may be relo-

cated to the left side of the furnace. Remove the screws and cut wire tie

holding excess wiring. Reposition on the left side of the furnace and fas-

ten using holes provided.

BLOWER

COMPARTMENT

COMBUSTION

AIR

VENT PIPE

1. Provide a power supply separate from all other circuits. Install

overcurrent protection and disconnect switch per local/national

electrical codes. The switch should be close to the unit for conve-

nience in servicing. With the disconnect or fused switch in the OFF

position, check all wiring against the unit wiring label. Refer to the

wiring diagram shown in Figure 41.

CLASS 2 SYSTEM

CONTROL WIRING

TO THERMOSTAT

IGNITION

MODULE

TRANSFORMER

(BLK) LI (HOT)

(WHT) N

(GRN)GND

2. Remove the screws retaining the junction box cover. Route the

power wiring through the opening in the unit into the junction box

with a conduit connector or other proper connection. In the junc-

tion box there will be three wires, a Black Wire, a White Wire and a

Green Wire. Connect the power supply as shown on the unit-wir-

ing label on the inside of the blower compartment door or Figure

10. The black furnace lead must be connected to the L1 (hot) wire

from the power supply. The white furnace lead must be connected

to neutral. Connect the green furnace lead (equipment ground) to

the power supply ground. An alternate wiring method is to use a

field provided 2” (5.08 cm) x 4” (10.2 cm) box and cover on the

outside of the furnace. Route the furnace leads into the box using

a protective bushing where the wires pass through the furnace

panel. After making the wiring connections replace the wiring box

cover and screws.

JUNCTION

BOX

FIGURE 10: Electrical Wiring

LOW VOLTAGE CONTROL WIRING CONNECTIONS

Install the field-supplied thermostat by following the instructions that

come with the thermostat. With the thermostat set in the OFF position

and the main electrical source disconnected, connect the thermostat

wiring from the wiring connections on the thermostat to the terminal

board on the ignition module, as shown in Figure 11. Electronic thermo-

stats may require the common wire to be connected as shown with the

dashed line in Figure 11. Apply strain relief to thermostat wires passing

through cabinet. If air conditioning equipment is installed, use thermo-

stat wiring to connect the Y and C terminals on the furnace control

board to the yellow and brown wires on the condensing unit (unit out-

side). Refer to Figure 11.

3. The furnace's control system requires correct polarity of the power

supply and a proper ground connection. If the power supply polar-

ity is reversed, the control board will flash 9 times. The furnace will

not operate until the polarity is corrected. Refer to “Furnace Diag-

nostics” section of the “User’s Information, Maintenance, & Ser-

vice Manual” provided with this furnace.

IMPORTANT: Set the heat anticipator in the room thermostat to 0.45

amps. Setting it lower will cause short cycles. Setting it higher will cause

the room temperature to exceed the set points.Some electronic thermo-

stats do not have adjustable heat anticipators. They may have other

type cycle rate adjustments. Follow the thermostat manufacturer's

instructions.

The 24-volt, 40 VA transformer is sized for the furnace components

only, and should not be connected to power auxiliary devices such as

humidifiers, air cleaners, etc. The transformer may provide power for an

air conditioning unit contactor.

For additional connection diagrams for all UPG equipment refer to “Low

Voltage System Wiring” document available online at www.upgnet.com

in the Product Catalog Section.

Unitary Products Group

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FIGURE 11: Thermostat Chart

Unitary Products Group

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ACCESSORY CONNECTIONS

TWINNING DUCT SYSTEM

The furnace control will allow power-switching control of various acces-

sories. Refer to Figure 12, for connection details.

Twinned furnaces must only be applied on a common duct system. A

single air supply plenum must be used for both furnaces and coil(s).

Separate plenums and supply ducts systems cannot be utilized. A sin-

gle return air plenum, common to both furnaces must be used.

HUM. HOT

BLK

115 VOLT

HUMIDIFER

Both furnaces must be identical models in both heating capacity and

CFM capacity. Both furnaces must be operated on the same motor

speed tap. See typical application, Figure 13.

WHT

EAC

SWITCHED

HUM CIRCUITS

If furnace staging is desired with two single stage furnaces on a com-

mon duct, where the gas burner on the first furnace operates on W1

and the gas burner on the second furnace operates on W2, then the

use of an air-mixing device in the plenum to mix the air from both fur-

naces is strongly recommended. The mixing device must be installed

before any ducts that supply air to occupied spaces. Twinning causes

both indoor fans to operate simultaneously. If a mixing device is not

used, any ducts that are connected down stream from the furnace that

operates on W2, will be supplying cold air in the Heating mode to the

occupied spaces unless W2 is energized.

EAC HOT

115 VOLT

ELECTRONIC

AIR CLEANER

BLK

WHT

NEUTRALS

FIGURE 12: Accessory Connections

VENT PIPE

ELECTRONIC AIR CLEANER CONNECTION

Two 1/4” (0.64 cm) spade terminals (EAC and NEUTRAL) for electronic

air cleaner connections are located on the control board. The terminals

provide 115 VAC (1.0 amp maximum) during circulating blower opera-

tion.

GAS SUPPLY

ELECTRICAL

(BOTH SIDES)

SUPPLY

HUMIDIFIER CONNECTION

Two 1/4” (0.64 cm) spade terminals (HUM and NEUTRAL) for humidi-

fier connections are located on the control board. The terminals provide

115 VAC (1.0 amp maximum) during heating system operation.

1 COIL FOR

EACH FURNACE

SUPPLY

AIR

SECTION VI: TWINNING AND STAGING

NOTE: You can twin two furnaces that have the same integrated control

module. Check the part number on the integrated control module. You

cannot twin two furnaces that have different integrated control module

part numbers. If the part numbers of the two integrated control modules

are different they may not communicate with each other so they will not

work in a twinning application.

FIGURE 13: Typical Twinned Furnace Application

IMPORTANT: When two furnaces are twinned, typical system total air-

flow will be approximately 85% of additive individual furnaces, i.e., two

2000 CFM (56.6 m³/m) units will yield a total 3400 CFM (96.3 m³/m).

In applications where more heating capacity or more airflow capacity is

needed than what one furnace can deliver, twinning can be used to

make two furnaces operate in tandem. When two furnaces are installed

using the same duct system, it is very important that the two furnace cir-

culating air blowers operate in unison. If one blower starts before the

second blower, the duct system will become pressurized and the blower

on the second furnace will turn backwards causing the second furnace

to overheat, resulting in damage to the furnace. Twinning is used to

make two furnaces operate in tandem, using one duct system, one

room thermostat and causing both furnaces to turn on and off simulta-

neously.

GAS PIPING

Furnace gas supplies must be provided as specified with these instruc-

tions. Since the furnaces are side by side, with no space between, gas

supplies must enter on the right and left respectively. All gas piping

must be in accordance with the national fuel gas code, ANSI Z223.1,

latest edition, and/or all local code or utility requirements.

TWINNING

In applications where more heating capacity or more airflow capacity is

needed than what one furnace can deliver, twinning can be used to

make two furnaces operate in tandem, using one duct system and one

room thermostat. When one duct system is used for two furnaces, it is

necessary that the two blowers operate in unison. The twinning function

of the board in this furnace ensures that both blowers turn on and off

simultaneously, and operate on the same blower speed.

Before installing the relay and wiring, disconnect electrical power to

both furnaces. Failure to cut power could result in electrical shock

or equipment damage.

Single-Wire Twinning

The control in the furnace has the single-wire twinning feature. With this

feature, a single wire is connected between the TWIN terminal on one

furnace board to the TWIN terminal on the second furnace board. The

board then communicates the blower status from one furnace to the

other along this wire. This communication makes the second furnace

blower come on at the same time, and on the same speed, as the first

furnace blower.

The relay must not be installed in any location where it could be

exposed to water. If the relay has been exposed to water in any

way, it must not be used.

Unitary Products Group

268890-UIM-B-0607

Single-Wire Twinning Instructions

Single-Wire Staging Instructions

Connect the control wiring as shown in the Figure 15.

Connect the control wiring as shown in the Figure 14.

1. Connect the low voltage wiring from the wall thermostat to the ter-

minal strip on the control board of Furnace #1. For staging applica-

tions, the wire from thermostat W1 is connected to the W

connection on the board on Furnace #1. The wire from thermostat

W2 is connected to Furnace #2 through a separate relay, as

described below.

1. Connect the low voltage wiring from the wall thermostat to the ter-

minal strip on the control board of Furnace #1.

2. Connect a wire from the TWIN terminal of Furnace #1 to the TWIN

terminal of Furnace #2.

3. Install a separate 24V relay as shown in the diagram below. Use of

this relay is required, as it ensures that the transformers of the two

furnaces are isolated, thus preventing the possibility of any safety

devices being bypassed.

2. Connect a wire from the TWIN terminal of Furnace #1 to the TWIN

terminal of Furnace #2.

3. Install a separate 24V relay as shown in the diagram below. Use of

this relay is required, as it ensures that the transformers of the two

furnaces are isolated, thus preventing the possibility of any safety

devices being bypassed.

Single-Wire Twinning Operation

Heating - On a call for heat (W signal) from the wall thermostat, both

furnaces will start the ignition sequence and the burners on both fur-

naces will light. About thirty seconds after the burners light, the blowers

on both furnaces will come on in heating speed. When the thermostat is

satisfied, the burners will all shut off and, after the selected blower off

delay time, both blowers will shut off at the same time. The twinning

control ensures that both blowers come on and shut off at the same

time.

Single-Wire Staging Operation

Heating - On a call for first-stage heat (W1 signal) from the wall thermo-

stat, Furnace #1 will start the ignition sequence and the burners will

light. About thirty seconds after the burners light, the blowers on both

furnaces will come on in heating speed. When the thermostat is satis-

fied, the burners will shut off and, after the selected blower off delay

time, both blowers will shut off at the same time. On a call for second

stage of heat, the burners of Furnace #2 will also light and both blowers

will run. The twinning control ensures that both blowers come on and

shut off at the same time.

Cooling - On a call for cooling (Y signal) from the wall thermostat, both

furnace blowers will come on at the same time in cooling speed. When

the thermostat is satisfied, both blowers will stay on for 60 seconds,

then will shut off at the same time.

Continuous Fan - On a thermostat call for continuous fan (G signal),

both furnace blowers will come on at the same time in cooling speed

and will stay on until the G signal is removed.

Cooling - On a call for cooling (Y signal) from the wall thermostat, both

furnace blowers will come on at the same time. When the thermostat is

satisfied, both blowers will stay on for 60 seconds, then will shut off at

the same time.

FURNACE 2 CONTROL BOARD

FURNACE 1 CONTROL BOARD

Continuous Fan - On a thermostat call for continuous fan (G signal),

both furnace blowers will come on at the same time in cooling speed

and will stay on until the G signal is removed.

FURNACE 2 CONTROL BOARD

FURNACE 1 CONTROL BOARD

TWIN

ISOLATION

RELAY

TWIN

ISOLATION

RELAY

TO A/C

WALL THERMOSTAT

FIGURE 14: Single Stage Twinning Wiring Diagram

TO A/C

STAGING

WALL THERMOSTAT

In applications where more heating capacity or more airflow capacity is

needed than what one furnace can deliver, twinning can be used to

make two furnaces operate in tandem, using one duct system and one

room thermostat. This control can also be used along with a two-stage

wall thermostat to stage two twinned furnaces, making them operate

like a single two-stage furnace. This allows only one furnace to supply

heat during times when the heat output from one furnace is sufficient to

satisfy the demand. When one duct system is used for two furnaces, it

is necessary that the two blowers operate in unison. The twinning func-

tion of this board ensures that both blowers turn on and off simulta-

neously, and operate on the same blower speed. Even when only one

furnace is supplying heat, both furnace blowers must run.

FIGURE 15: Two-Stage Twinning Wiring Diagram

SECTION VII: COMBUSTION AIR AND

VENT SYSTEM

COMBUSTION AIR AND VENT SAFETY

This Category IV, dual certified direct vent furnace is designed for resi-

dential application. It may be installed without modification to the con-

densate system in a basement, garage, equipment room, alcove, attic

or any other indoor location provided the space temperature is 32 °F

(0°C) or higher and where all required clearance to combustibles and

other restrictions are met. The combustion air and the venting system

must be installed in accordance with Section 5.3, Air for Combustion

and Ventilation, of the National Fuel Gas Code Z223.1/NFPA 54 (latest

edition), or Sections 7.2, 7.3 or 7.4 of CSA B149.1, National Gas and

Propane Codes (latest edition) or applicable provisions of the local

building code and these instructions.

Single-Wire Staging

The single-wire twinning feature of this board can also be used for stag-

ing of two furnaces. With this feature, a single wire is connected

between the TWIN terminal on one furnace board to the TWIN terminal

on the second furnace board. The board then communicates the blower

status from one furnace to the other along this wire. This communica-

tion makes the second furnace blower come on at the same time, and

on the same speed, as the first furnace blower.

IMPORTANT: The “VENT SYSTEM” must be installed as specified in

these instructions for Residential and Non HUD Modular Homes. The

sealed combustion air / vent system is the only configuration that can

be installed in a Non HUD Modular Home.

Unitary Products Group

268890-UIM-B-0607

TABLE 8: Maximum Equivalent Pipe Length

Maximum

Equivalent

length feet (m)

Model Input

BTUH (kW)

Pipe Size

Inches (cm)

This furnace may not be common vented with any other appliance,

since it requires separate, properly sized air intake and vent lines.

The furnace shall not be connected to any type of B, BW or L vent

or vent connector, and not connected to any portion of a factory-

built or masonry chimney

40,000 (11.7)

60,000 (17.6)

80,000 (23.4)

100,000 (29.3)

120,000 (29.3)

2 (5.1)

3 (7.6)

2 (5.1)

3 (7.6)

2 (5.1)

3 (7.6)

2 (5.1)

3 (7.6)

65 (19.8)

90 (27.4)

65 (19.8)

90 (27.4)

65 (19.8)

90 (27.4)

30 (9.2)

The furnace shall not be connected to a chimney flue serving a sep-

arate appliance designed to burn solid fuel.

When combustion air pipe is installed above a suspended ceiling or

when it passes through a warm and humid space, the pipe must be

insulated with 1/2” Armaflex or other heat resistant type insulation.

Vent piping must be insulated with 1/2” insulation if it will be sub-

jected to freezing temperatures such as routing through unheated

areas or through an unused chimney.

85 (25.9)

60 (18.3)

TABLE 9: Equivalent Length of Fittings

Fitting

Equivalent Length

5 feet of 2" pipe

2-1/2 feet of 2" pipe

10 feet of 2" pipe

5 feet of 2" pipe

5 feet of 3" pipe

2-1/2 feet of 3" pipe

10 feet of 3" pipe

5 feet of 3" pipe

10 feet of 2" pipe

10 feet of 3" pipe

COMBUSTION AIR/VENT PIPE SIZING

The size of pipe required will be determined by the furnace model, the

total length of pipe required and the number of elbows required.

2" 90º sweep elbow

2" 45º sweep elbow

2" 90º standard elbow

2" 45º standard elbow

3" 90º sweep elbow

3" 45º sweep elbow

3" 90º standard elbow

3" 45º standard elbow

2" corrugated connector

3" corrugated connector

Table 8 lists the maximum equivalent length of pipe allowed for each

model of furnace. The equivalent length of elbows is shown in Table 9.

The equivalent length of the vent system is the total length of straight

pipe PLUS the equivalent length of all of the elbows.

The following rules must also be followed:

1. Long radius (sweep) elbows are recommended. Standard elbows

may be used, but since they have a longer equivalent length, they

will reduce the total length of pipe that will be allowed. Short radius

(plumbing vent) elbows are not allowed. The standard dimensions

of the acceptable elbows are shown below.

Example:

An 80,000 BTUH furnace requires 32 feet of pipe and four 90º elbows.

Using 2" pipe and standard elbows, the total equivalent length will be:

2. The maximum equivalent length listed in Table 8 is for the vent pip-

ing and the air intake piping separately. For example, if the table

allows 65 equivalent feet for a particular model, then the vent can

have 65 equivalent feet of pipe, AND the combustion air intake can

have another 65 equivalent feet of pipe.

32 feet of 2" pipe =

4 - 90º standard 2" elbows = (4x10) =

Total =

32 equivalent feet

40 equivalent feet

72 equivalent feet of 2" pipe

3. Three vent terminal elbows (two for the vent and one for the com-

bustion air intake) are already accounted for and need not be

included in the equivalent length calculation.

This exceeds the 65 foot maximum equivalent length of 2" pipe allowed

for that model and is thus not acceptable.

4. All combustion air and vent pipe must conform to American

National Standards Institute (ANSI) and American Society for Test-

ing and Materials (ASTM) standards D1785 (Schedule 40 PVC),

D2665 (PVC-DWV), F891 (PVC-DWV Cellular Core), D2261

(ABS-DWV) or F628 (Schedule 40 ABS). Pipe cement and primer

must conform to ASTM Standard D2546 (PVC) or D2235 (ABS). If

ABS pipe is to be used, any joint where ABS pipe is joined to PVC

pipe must be glued with cement that is approved for use with

BOTH materials. Metallic materials must not be used for venting or

air intake.

By using sweep elbows, the total equivalent length will be:

32 feet of 2" pipe =

4 - 90º standard 2" elbows = (4x5) =

Total =

32 equivalent feet

20 equivalent feet

52 equivalent feet of 2" pipe

This is less than the 65 foot maximum equivalent length of 2" pipe

allowed for that model and is thus acceptable.

Alternatively, using 3" pipe and standard elbows, the total equivalent

length will be:

5. If a flexible connector is used in the vent system, it must be made

of a material that is resistant to acidic exposure and to at least

225° F temperature. Flexible connectors are also allowed in the

combustion air pipe.

32 feet of 3" pipe =

4 - 90º standard 2" elbows = (4x5) =

Total =

32 equivalent feet

40 equivalent feet

72 equivalent feet of 3" pipe

6. All models are supplied with 2" vent connections. When the pipe

must be increased to 3" diameter, the transition from 2" to 3" must

be done as close to the furnace as possible. For upflow models,

the transition from 2" to 3" should be done immediately above the

furnace. For downflow or horizontal models, the transition from 2"

to 3" pipe should be done immediately after the drain tee or drain

elbow.

This is less than the 90 foot maximum equivalent length of 3" pipe

allowed for that model and is thus acceptable.

7. In Canada, vents shall be certified to ULC S636, Standard for Type

BH Gas Venting Systems. IPEX System 636 PVC is certified to

this standard.

8. In Canada, the first three feet (900 mm) of the vent must be readily

accessible for inspection.

Unitary Products Group

268890-UIM-B-0607

COMBUSTION AIR AND VENT PIPING ASSEMBLY

The final assembly procedure for the combustion air and vent piping is

as follows:

1. Cut piping to the proper length beginning at the furnace.

2. Deburr the piping inside and outside.

3. Chamfer (bevel) the outer edges of the piping.

4. Dry-fit the vent piping assembly from the furnace to the outside ter-

mination checking for proper fit support and slope.

5. Dry-fit the combustion air piping assembly checking for proper fit,

support and slope on the following systems:

STANDARD ELBOW

LONG (SWEEP) ELBOW

A. Sealed combustion air systems from the furnace to the out-

side termination.

FIGURE 16: Dimensions

B. Ventilated combustion air systems from the furnace to the

attic or crawl space termination.

TABLE 10: Elbow Dimensions

Elbow

"A" Dimension

2" Standard

3" Standard

2" Sweep

3" Sweep

2-5/16"

3-1/16"

3-1/4"

Solvent cements are flammable and must be used in well-ventilated

areas only. Keep them away from heat, sparks and open flames.

Do not breathe vapors and avoid contact with skin and eyes.

4-1/16"

6. Disassemble the combustion air and vent piping, apply cement

primer and the cement per the manufactures instructions. Primer

and cement must conform to ASTM D2564 for PVC, or ASTM

D2235 for ABS piping.

Dimensions are those required in Standard ASTM D-3311.

NOTE: Sidewall vent terminal may be used for sidewall vent termina-

tions. Refer to part list in the back of the USERS INFORMATION AND

SERVICE AND MAINTENANCE MANUAL for the terminal part number.

7. All joints must provide a permanent airtight and watertight seal.

TABLE 11: Combustion Air Intake and Vent Connection Size at Furnace

8. Support the combustion air and vent piping such that it is angled a

minimum of 1/4” per foot (0.635 cm/m) so that condensate will flow

back towards the furnace. Piping should be supported with pipe

hangers to prevent sagging.

(All Models)

FURNACE VENT CONNECTION SIZES

40 - 100 MBH

(17.5 - 29.3 kW)

120 MBH

(35.2 kW)

9. Seal around the openings where the combustion air and / or vent

piping pass through the roof or sidewalls.

Furnace Input

Intake Pipe Size

Vent Pipe Size

2” (5.1 cm)

3” (7.6 cm)

2” (5.1 cm)

COMBUSTION AIR / VENT CLEARANCES

IMPORTANT: The vent must be installed with the minimum clearances

as shown in Figure 17, and must comply with local codes and require-

ments.

*. Vent pipe size must be increased to 3” diameter after connection to furnace

on this model.

IMPORTANT: Accessory concentric vent

intake termination kits

1CT0302 and 1CT0303 are available and approved for use with these

furnaces. Horizontal sidewall vent terminations kits 1HT0901

1HT0902 are also approved for use with these furnaces.

IMPORTANT: Furnace vent pipe connections are sized for 2” (5.1 cm).

pipe. Any pipe size change must be made outside the furnace casing in

a vertical pipe section to allow proper drainage of condensate. An offset

using two 45º (degree) elbows will be required for plenum clearance

when the vent is increased to 3” (7.6 cm).

Unitary Products Group

268890-UIM-B-0607

VENT CLEARANCES

VENT TERMINAL

AIR SUPPLY

FIXED

CLOSED

AREA WHERE TERMINAL IS NOT PERMITTED

FIXED

CLOSED

OPERABLE

FIGURE 17: Home Layout

Canadian Installations^1,3

US Installation^2,3

Direct Vent Terminal Clearances

A. Clearance above grade, veranda, porch, deck, or

balcony

12 inches (30 cm)

Two-pipe (direct vent) applications: 9 inches (23 cm)

for models ≤50,000 BTUH (15 kW), 12 inches (30 cm)

for models >50,000 BTUH (15 kW). ††

12 inches (30 cm) for models ≤100,000 BTUH (30 kW),

36 inches (91 cm) for models >100,000 BTUH (30 kW)

B. Clearance to window or door that may be opened

C. Clearance to permanently closed window

12 inches (30 cm)

D. Vertical clearance to ventilated soffit located

above the terminal within a horizontal distance