Bryant 373LAV User Manual

installation, start-up,	373LAV
and operating instructions	Series G

DOWNFLOW/HORIZONTAL

GAS-FIRED

INDUCED-COMBUSTION FURNACES

NOTE: Read the entire instruction manual before starting the
installation.
This symbol → indicates a change since the last issue.
Index	Page
SAFETY CONSIDERATIONS .....................................................	1
Dimensional Drawing ...............................................................	2
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS
PROCEDURE ...........................................................................	2
INTRODUCTION ..........................................................................	3
Clearances From Combustible Materials .................................	3
LOCATION....................................................................................	4
General ......................................................................................	4
Location Relative to Cooling Equipment ................................	4
Hazardous Locations.................................................................	4
AIR FOR COMBUSTION AND VENTILATION ...................	4-5
Unconfined Space..................................................................	4-5
Confined Space .........................................................................	5
AIR DUCTS...................................................................................	5
General Requirements...............................................................	5
Ductwork Acoustical Treatment...............................................	5
Supply-Air Connections............................................................	5
Return-Air Connections ............................................................	5
DOWNFLOW INSTALLATION ..................................................	6
HORIZONTAL ATTIC INSTALLATION................................	6-7
Construct a Working Platform ..............................................	6-7
Install Furnace...........................................................................	7
HORIZONTAL CRAWLSPACE INSTALLATION....................	7
FILTER ARRANGEMENT...........................................................	7
GAS PIPING.............................................................................	7-10
ELECTRICAL CONNECTIONS ................................................	10
115-v Wiring...........................................................................	10
24-v Wiring.............................................................................	10
Accessories ........................................................................	10-11
VENTING ....................................................................................	11
START-UP, ADJUSTMENT, AND SAFETY CHECK ............	11
General ....................................................................................	11
Sequence Of Operation...........................................................	11
Heating Mode..........................................................................	11
Cooling Mode .........................................................................	14
Continuous Blower Mode.......................................................	14
Heat Pump Mode ....................................................................	14
Start-up Procedures .................................................................	14
Adjustments .......................................................................	14-20
Set Gas Input Rate..................................................................	14
Set Temperature Rise..............................................................	15
Set Thermostat Heat Anticipator............................................	18
Check Safety Controls.......................................................	18-19
Checklist ............................................................................	19-20
SAFETY CONSIDERATIONS
Installing and servicing heating equipment can be hazardous due to
gas and electrical components. Only trained and qualified person-
nel should install, repair, or service heating equipment.
Untrained personnel can perform basic maintenance functions
such as cleaning and replacing air filters. All other operations must

Cancels: II 373L-35-20	II 373L-35-21
	7-99

ama

CANADIAN GAS ASSOCIATION

®

A PP R O VED

R

REGISTERED QUALITY SYSTEM

be performed by trained service personnel. When working on heating equipment, observe precautions in the literature, on tags, and on labels attached to or shipped with the unit and other safety precautions that may apply.

→In the United States, follow all safety codes including the National Fuel Gas Code (NFGC) NFPA 54-1996/ANSI Z223.1-1996 and the Installation Standards, Warm Air Heating and Air Conditioning Systems (NFPA 90B) ANSI/NFPA 90B.

→In Canada, refer to the CAN/CGA-B149.1- and .2-M95 National Standard of Canada, Natural Gas and Propane Installation Codes (NSCNGPIC).

Wear safety glasses and work gloves. Have fire extinguisher available during start-up and adjustment procedures and service calls.

Recognize safety information. This is the safety-alert symbol . When you see this symbol on the unit and in instructions or manuals, be alert to the potential for personal injury.

→Understand the signal words DANGER, WARNING, CAUTION, and NOTE. These words are used with the safety-alert symbol. DANGER identifies the most serious hazards which will result in severe personal injury or death. WARNING signifies a hazard which could result in personal injury or death. CAUTION is used to identify unsafe practices which would result in minor personal injury or product and property damage. NOTE is used to highlight suggestions which will result in enhanced installation, reliability, or operation.

These instructions cover minimum requirements and conform to existing national standards and safety codes. In some instances, these instructions exceed certain local codes and ordinances, especially those that may not have kept up with changing residential construction practices. We require these instructions as a minimum for a safe installation.

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28 1⁄2²

VENT CONNECTION

1⁄2² DIA

20²

D

4

3⁄ ²

2²

13⁄ ²

THERMOSTAT

13

⁄16²

16

WIRE ENTRY

INLET

16

7⁄8² DIA

2 15⁄16²

ACCESSORY

7⁄8² DIA HOLE

39 7⁄8²

POWER ENTRY

1 1⁄2² DIA

7⁄8² DIA

9 1⁄8²

R.H. GAS ENTRY

ACCESSORY

1 3⁄4² DIA HOLE

10

1

⁄4²

16 1⁄16²

7⁄8² DIA

1² TYP

GAS ENTRY

ACCESSORY

11

16

²

OUTLET

1

1⁄16²

E

13 5 ⁄ ²

16

⁄

2

1⁄²

5

⁄8² TYP

10 1⁄4²

19²

8

8

A

11

1⁄

⁄16²

1 1⁄16²

4²

11⁄ ²

2 1⁄8²

16

NOTE: ADDITIONAL 7⁄8² DIA K.O. ARE

AIRFLOW

DIMPLES TO DRILL HOLES

LOCATED IN THE TOP PLATE

FOR HANGER BOLTS (4 PLACES)

AND BOTTOM PLATE

IN HORIZONTAL POSITION

NOTES: 1. Two additional 7⁄8-in. dia holes are located in the top plate.

2.Minimum return-air openings at furnace, based on metal duct. If flex duct is used, see flex duct manufacturer's recommendations for equivalent diameters.

a.For 800 CFM–16-in. round or 141⁄2 x 12-in. rectangle.

b.For 1200 CFM–20-in. round or 141⁄2 x 191⁄2-in. rectangle.

c.For 1600 CFM–22-in. round or 141⁄2 x 231⁄4-in. rectangle.

d.For airflow requirements above 1800 CFM, must use entire return air opening.

A99109

→Fig. 1ÐDimensional Drawing

→TABLE 1ÐDIMENSIONS (IN.)

UNIT SIZE	A	D	E	VENT CONN	SHIP. WT (LB)
024050	14-3/16	12-9/16	12-11/16	4	121
036050	14-3/16	12-9/16	12-11/16	4	130
024070	14-3/16	12-9/16	12-11/16	4	129
036070	14-3/16	12-9/16	12-11/16	4	138
036095	17-1/2	15-7/8	16	4	150
048095	17-1/2	15-7/8	16	4	152
048115	17-1/2	15-7/8	16	4	158
060115	21	19-3/8	19-1/2	4	175
060135	24-1/2	22-7/8	23	5	192

ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS

PROCEDURE

CAUTION: Electrostatic discharge can affect electronic components. Take precautions during furnace installation and servicing to protect the furnace electronic control. Precautions will prevent electrostatic discharges from personnel and hand tools which are held during the procedure. These precautions will help to avoid exposing the control to electrostatic discharge by putting the furnace, the control, and the person at the same electrostatic potential.

1.Disconnect all power to the furnace. DO NOT TOUCH THE CONTROL OR ANY WIRE CONNECTED TO THE CONTROL PRIOR TO DISCHARGING YOUR BODY'S ELECTROSTATIC CHARGE TO GROUND.

2.Firmly touch a clean, unpainted, metal surface of the furnace chassis which is close to the control. Tools held in a person's hand during grounding will be satisfactorily discharged.

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3.After touching the chassis you may proceed to service the control or connecting wires as long as you do nothing that recharges your body with static electricity (for example; DO NOT move or shuffle your feet, DO NOT touch ungrounded objects, etc.).

4.If you touch ungrounded objects (recharge your body with static electricity), firmly touch furnace again before touching control or wires.

5.Use this procedure for installed and uninstalled (ungrounded) furnaces.

6.Before removing a new control from its container, discharge your body's electrostatic charge to ground to protect the control from damage. If the control is to be installed in a furnace, follow items 1 through 5 before bringing the control or yourself into contact with the furnace. Put all used AND new controls into containers before touching ungrounded objects.

7.An ESD service kit (available from commercial sources) may also be used to prevent ESD damage.

MINIMUM INCHES CLEARANCE TO COMBUSTIBLE CONSTRUCTION

This forced air furnace is equipped for use with natural gas at altitudes 0-10,000 ft (0-3,050m).

An accessory kit, supplied by the manufacturer,shall be used to convert to propane gas use or may be required for some natural gas applications.

This furnace is for indoor installation in a building constructed on site.

This furnace may be installed on combustible flooring in alcove or closet at minimum clearance from combustible material.

This furnace may be used with a Type B-1 Vent and may be vented in common with other gas-fired appliances.

†For installation on non-combustible floors only. For installation on combustible flooring only when

installed on special base, Part No. KGASB0201ALL, Coil Assembly, Part No. CD5 or CK5, or Coil Casing, Part No. KCAKC.

# For furnaces wider than 14.25 inches (362mm) may be 0 inches.

Ø 18 inches front clearance required for alcove.

* Indicates supply or return sides when furnace is in the horizontal position. Line contact only permissible between lines formed by intersections of the Top and two Sides of the furnace jacket, and building joists, studs or framing.

## For single wall vent type 6 inches. For Type B-1 vent type 3 inches.

†† Clearance to Back 0 inches in downflow and horizontal (attic/alcove & crawlspace) positions and 3 inches in horizontal closet positions.

This furnace is approved for DOWNFLOW and HORIZONTAL installations.

Clearance arrows
do not change with	1"
furnace orientation.

0"	†
		B A
†			C K

	E
I	D
S

*1" #

Clearance in inches

PLENUM/

TOP

FURNACE FRONT

F R O N T

	BOTTOM
	" #
†	1

	1"
E	*	#
ID
S

S E

R VI C E 30"

MIN

##

Ø

Vent Clearance to combustibles:

For Single Wall vents 6 inches.

For Type B-1 vent type 1 inch .

322286-101 REV. F (LIT)

A99262

Fig. 2ÐClearances to Combustibles

INTRODUCTION

→The model 373LAV Series G Furnaces are available in sizes 46,000 through 135,000 Btuh input capacities.

The design of the downflow/horizontal gas-fired furnace is A.G.A./C.G.A. certified for natural and propane gases and for installation on noncombustible flooring. The furnace is factoryshipped for use with natural gas. A factory accessory gas conversion kit, as listed on the furnace rating plate is required to convert furnace for use with propane gas.

These furnaces SHALL NOT be installed directly on carpeting, tile, or any other combustible material other than wood flooring. In downflow installations, a factory accessory floor base, as listed on the furnace rating plate MUST be used when installed on combustible materials and wood flooring. A factory floor base is not required when this furnace is installed on manufacturer's Coil Assembly Part No. CD5 or CK5, or when Coil Box Part No. KCAKC is used. This furnace is for installation in alcoves, attics, crawlspaces, basements, closets, or utility rooms. The design of this furnace line is not A.G.A./C.G.A. certified for installation in mobile homes, recreation vehicles, or outdoors.

→Before installing the furnace in the United States, refer to the NFGC and NFPA 90B. For copies of the NFGC and NFPA 90B, contact the National Fire Protection Association Inc., Batterymarch Park, Quincy, MA 02269; or for only the NFGC contact the American Gas Association, 400 N. Capitol St., NW, Washington DC 20001.

→Before installing the furnace in Canada, refer to the NSCNGPIC. For a copy of the NSCNGPIC, contact Standard Sales, CSA International, 178 Rexdale Boulevard, Etobicoke (Toronto), Ontario, M9W 1R3, Canada.

→Installation must comply with regulations of serving gas supplier and local building, heating, plumbing or other codes in effect in the area in which installation is made. In absence of local building codes, installation must conform with NFGC in the United States and the NSCNGPIC and all authorities having jurisdiction in Canada.

These instructions cover minimum requirements for a safe installation and conform to existing national standards and safety codes. In some instances, these instructions exceed certain local codes and ordinances, especially those that may not have kept pace with changing residential construction practices. We require these instructions as a minimum for a safe installation.

CAUTION: Application of this furnace should be indoors with special attention given to vent sizing and material, gas input rate, air temperature rise, and unit sizing. Improper installation or misapplication of the furnace can require excessive servicing or cause premature component failure.

This furnace is designed for a minimum continuous return-air temperature of 60°F db or intermittent operation down to 55°F db such as when used with a night setback thermostat. Return-air temperature must not exceed a maximum of 85°F db.

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→ C. Hazardous Locations

WARNING: Improper installation, adjustment, alteration, service, maintenance, or use can cause carbon monoxide poisoning, explosion, fire, electrical shock, or other conditions which may cause personal injury, loss of life, or property damage. Consult a qualified installer, service agency, local gas supplier, or your distributor or branch for information or assistance. The qualified installer or agency must use only factory-authorized and listed kits or accessories when modifying this product.

Failure to follow this warning could result in electrical shock, fire, personal injury, or death.

For accessory installation details, refer to the applicable installation literature.

NOTE: Remove all shipping brackets and materials before operating the furnace.

I.LOCATION

A.General

CAUTION: Do not install furnace in a corrosive or contaminated atmosphere. Make sure all combustion and circulating air requirements are followed, in addition to all local codes and ordinances.

CAUTION: Do not use this furnace during construction when adhesives, sealers, and/or new carpets are being installed. If the furnace is required during construction, use clean outside air for combustion and ventilation. Compounds of chlorine and fluorine when burned with combustion air form acids which cause corrosion of the heat exchangers and metal vent system. Some of these compounds are found in paneling and dry wall adhesives, paints, thinners, masonry cleaning materials, and many other solvents commonly used in the construction process.

Excessive exposure to contaminated combustion air will result in safety and performance related problems.

This furnace must be installed so the electrical components are protected from water.

Locate the furnace as close to the chimney/vent and as near the center of the air distribution system as possible. The furnace should be installed as level as possible.

Provide ample space for servicing and cleaning. Always comply with the minimum fire protection clearances shown on the unit rating plate. This furnace shall not be installed directly on carpeting, tile, or any combustible material other than wood flooring. The furnace may be installed on combustible flooring when installed with the accessory downflow subbase, which is available from your distributor or branch when required.

B.Location Relative to Cooling Equipment

The cooling coil must be installed parallel with or on the downstream side of the furnace to avoid condensation in the heat exchangers. When installed parallel with a furnace, dampers or other means used to control the flow of air must prevent chilled air from entering the unit. If the dampers are manually operated, they must be equipped with means to prevent operation of either unit unless the damper is in the full-heat or full-cool position.

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18-IN. MINIMUM

TO BURNERS

A93044

WARNING: When furnace is installed in a residential garage, it must be installed so that burners and ignition sources are located a minimum of 18 in. above floor. The furnace must be located or protected to avoid physical damage by vehicles. When furnace is installed in a public garage, airplane hangar, or other building having a hazardous atmosphere, unit must be installed in accordance with requirements of National Fire Protection Association, Inc.

II.AIR FOR COMBUSTION AND VENTILATION

Provisions for adequate combustion and ventilation air must be provided in accordance with Section 5.3 of the NFGC, Air for Combustion and Ventilation, or applicable provisions of the local building codes.

Canadian installations must be installed in accordance with NSCNGPIC and all authorities having jurisdiction.

CAUTION: Air for combustion must not be contaminated by halogen compounds, which include fluoride, chloride, bromide, and iodide. These elements are found in aerosol sprays, detergents, bleaches, cleaning solvents, salts, air fresheners, and other household products.

CAUTION: The operation of exhaust fans, kitchen ventilation fans, clothes dryers, or fireplaces could create a NEGATIVE PRESSURE CONDITION at the furnace. Make-up air MUST be provided for the ventilation devices, in addition to that required by the furnace.

All fuel-burning equipment must be supplied with air for combustion of the fuel. Sufficient air MUST be provided to ensure there will not be a negative pressure in the equipment room or space. In addition, a positive seal MUST be made between the furnace cabinet and the return-air duct to avoid pulling air from the burner area and blocked vent safeguard opening.

The requirements for combustion and ventilation air depend upon whether the furnace is located in an unconfined or confined space.

A.Unconfined Space

An unconfined space must have at least 50 cu ft for each 1000 Btuh of input for all the appliances (such as furnaces, clothes dryer, water heaters, etc.) in the space.

If the unconfined space is of unusually tight construction, air for combustion and ventilation MUST come from either the outdoors or spaces freely communicating with the outdoors. Combustion

and ventilation openings must be sized the same as for a confined space as defined below. Return air must not be taken from the room unless an equal or greater amount of air is supplied to the room.

For Example:

	373LAV FURNACE	MINIMUM SQ FT
		WITH
	INPUT BTUH
		7-1/2 FT CEILING
	46,000	307
	69,000	460
	92,000	613
	115,000	767
	135,000	920

→B. Confined Space

A confined space is defined as a space whose volume is less than 50 cu ft per 1000 Btuh of total input ratings of all appliances installed in that space. A confined space MUST have provisions for supplying air for combustion, ventilation, and dilution of flue gases using 1 of the following methods. (See Fig. 3, 4, and Table 2.)

NOTE: In determining free area of an opening, the blocking effect of louvers, grilles, and screens must be considered. If free area of louver or grille design is unknown, assume that wood louvers have a 20 percent free area and metal louvers or grilles have a 60 percent free area. Screens, when used, must not be smaller than 1/4-in. mesh. Louvers and grilles must be constructed so they cannot be closed.

The size of the openings depends upon whether air comes from outside of the structure or an unconfined space inside the structure.

1.All air from inside the structure requires 2 openings (for structures not usually tight):

a.Each opening MUST have at least 1 sq in. of free area per 1000 Btuh of total input for all equipment within the confined space, but not less than 100 sq in. per opening. (See Fig. 3 and Table 2.) The minimum dimension of air openings shall not be less than 3 in.

b.If building is constructed unusually tight, a permanent opening directly communicating with the outdoors shall be provided. See item 2 below.

c.If furnace is installed on a raised platform to provide a return-air plenum, and return air is taken directly from hallway or space adjacent to furnace, all air for combustion must come from outdoors.

2.Air from outside the structure requires 1 of the following methods:

a.If combustion air is taken from outdoors through 2 vertical ducts, the openings and ducts MUST have at least 1 sq in. of free area per 4000 Btuh of total input for all equipment within the confined space. (See Fig. 4 and Table 2.)

b.If combustion air is taken from outdoors through 2 horizontal ducts, the openings and ducts MUST have at least 1 sq in. of free area per 2000 Btuh of total input for all equipment within the confined space. (See Fig. 4 and Table 2.)

c.If combustion air is taken from outdoors through a single opening or duct (horizontal or vertical) commencing within 12 in. of the top of the confined space, opening and duct MUST have at least 1 sq in. of free area per 3000 Btuh of the total input for all equipment within the confined space and not less than the sum of the areas of

Ð5Ð

all vent connectors in the confined space. (See Fig. 4 and Table 2.) Equipment clearances to the structure shall be at least 1 in. from the sides and back and 6 in. from the front of the appliances.

When ducts are used, they must be of the same cross-sectional area as the free area of the openings to which they connect. The minimum dimension of ducts must not be less than 3 in. (See Fig. 4.)

→AIR DUCTS

WARNING: Never connect return-air ducts to the back of the furnace. A failure to follow this warning can cause a fire, personal injury, or death.

I.GENERAL REQUIREMENTS

The duct system should be designed and sized according to accepted national standards such as those published by: Air Conditioning Contractors Association (ACCA), Sheet Metal and Air Conditioning Contractors National Association (SMACNA) or American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE). Or consult factory The Air Systems Design Guidelines reference tables available from your local distributor. The duct system should be sized to handle the required system design CFM at the design static pressure.

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

Secure ductwork with proper fasteners for type of ductwork used. Seal supplyand return-air duct connections to furnace with code approved tape or duct sealer.

Flexible connections should be used between ductwork and furnace to prevent transmission of vibration. Ductwork passing through unconditioned space should be insulated to enhance system performance. When air conditioning is used, a vapor barrier is recommended.

Maintain a 1-in. clearance from combustible materials to supply air ductwork for a distance of 36 in. horizontally from the furnace. See NFPA 90B or local code for further requirements.

II.DUCTWORK ACOUSTICAL TREATMENT

Metal duct systems that do not have a 90 degree elbow and 10 ft of main duct to the first branch take-off may require internal acoustical lining. As an alternative, fibrous ductwork may be used if constructed and installed in accordance with the latest edition of SMACNA construction standard on fibrous glass ducts. Both acoustical lining and fibrous ductwork shall comply with NFPA 90B as tested by UL Standard 181 for Class 1 Rigid air ducts.

III.SUPPLY AIR CONNECTIONS

A.Downflow Furnaces

Connect supply-air duct to supply-air opening (outlet) on furnace. (See Fig. 1.) The supply-air duct attachment must ONLY be connected to furnace supply/outlet or air conditioning coil casing (when used), when installed on non-combustible material. When installed on combustible material, supply-air duct attachment must ONLY be connected to an accessory subbase or factory approved air conditioning coil casing. DO NOT cut main furnace casing to attach supply side air duct, humidifier, or other accessories. All accessories MUST be connected external to furnace main casing.

B.Horizontal Furnaces

Connect supply-air duct to supply-air (outlet) opening on furnace. (See Fig. 1.) The supply-air duct attachment must ONLY be connected to furnace supply/outlet or air conditioning coil casing (when used). DO NOT cut main furnace casing to attach supply side air duct, humidifier, or other accessories. All accessories MUST be connected external to furnace main casing.

			DUCTS TO
		OUTDOORS
					1 SQ IN.
					PER 4000
					BTUH*
	VENT THROUGH ROOF
	(CATEGORY I)
		12² MAX		D	12²
		1 SQ IN.	A RETURN	VENT	MAX
		PER 2000			F
RETURN		BTUH*	AIR	THROUGH
	12² MAX			ROOF
AIR				(CATEGORY I)	1 SQ IN.
	1 SQ IN.				PER 4000
					BTUH*
SPACE	PER 1000	DUCTS		CONFINED SPACE
	SPACE				1 SQ IN.
	BTUH* IN DOOR	TO			OUTDOORS
INTERIOR	OR WALL	OUTSIDE
	UNCONFINED
HEATED
	6² MIN				PER 4000
					BTUH*
	(FRONT) †	1 SQ IN.
	1 SQ IN.		B	E	G
		PER 2000
	PER 1000	BTUH*			12²
	BTUH* IN DOOR	12² MAX		C	MAX
	OR WALL			12² MAX
	12² MAX	SUPPLY AIR		DUCT
					1 SQ IN.
				TO
SUPPLY AIR				OUTDOORS	PER 4000
					BTUH
		*Minimum dimensions of 3 in.

*Minimum opening size is 100 sq in. with minimum dimensions of 3 in.

† Minimum of 3 in. when type B-1 vent is used.

NOTE: Use any of the following combinations of openings:

A & B C & D D & E F & G

A93387

A93388

Fig. 3ÐConfined Space: Air for Combustion and Ventilation from an Unconfined Indoor Space

Fig. 4ÐConfined Space: Air for Combustion and Ventilation from Outdoors

→TABLE 2ÐMINIMUM FREE AREA OF COMBUSTION AIR OPENING*

	373LAV	AIR FROM INDOOR	OUTDOOR AIR THROUGH		OUTDOOR AIR THROUGH		OUTDOOR AIR THROUGH
		UNCONFINED SPACE	VERTICAL DUCTS		HORIZONTAL DUCTS		SINGLE DUCT
	FURNACE
		Free Area	Free Area of	Round	Free Area of	Round	Free Area of	Round
	INPUT
		of Opening	Opening and Duct	Pipe	Opening and Duct	Pipe	Opening and Duct	Pipe
	(BTUH)
		(Sq In.)	(Sq In.)	(In. Dia)	(Sq In.)	(In. Dia)	(Sq In.)	(In. Dia)
	46,000	100	11.50	4	23.0	6	15.33	5
	69,000	100	17.25	5	34.5	7	23.00	6
	92,000	100	23.00	6	46.0	8	30.67	7
	115,000	115	28.75	7	57.5	9	38.33	7
	135,000	135	33.75	7	67.5	10	45.00	8

* Free area shall be equal to or greater than the sum of the areas of all vent connections in the confined space. Opening area must be increased, if other gas appliances in the space require combustion air.

IV. RETURN AIR CONNECTIONS

The return-air duct must be connected to return-air opening (inlet) provided as shown in Fig. 1. DO NOT cut into casing sides or back to attach any portion of return-air duct. Bypass humidifier connections should be made at ductwork or coil casing sides exterior to furnace.

V.DOWNFLOW INSTALLATION

NOTE: This furnace is approved for use on combustible materials or wood flooring. A factory accessory floor base, as listed on the furnace rating plate, MUST be used. A factory accessory floor base is not required when this furnace is installed on manufacturer's Coil Assembly Part No. CD5 or CK5, or Coil Box Part No. KCAKC is used.

3.Construct plenum to dimensions specified in Table 3.

4.If downflow subbase (KGASB) is used, install as shown in Fig. 6.

If coil assembly CD5, CK5, or Coil Box KCAKC is used, install as shown in Fig. 7.

VI. HORIZONTAL ATTIC INSTALLATION

WARNING: DO NOT install the furnace on its back; safety control operation will be adversely affected. Never connect return-air ducts to the sides or back of the furnace. Failure to follow this warning could result in fire, personal injury, or death.

1.Determine application being installed from Table 3.

2.Construct hole in floor per dimensions specified in Table 3 and Fig. 5.

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The furnace can be installed horizontally on either the left-hand (LH) or right-hand (RH) side. A typical attic installation is shown in Fig. 8.