Carrier WEATHERMAKER 8000 58ZAV Instruction Manual

WeatherMaker 8000™

Downflow/Horizontal Induced-Combustion Furnaces

Visit www.carrier.com

Installation, Start-Up, and Operating Instructions

Sizes 050—135, Series 151 and 161

NOTE: Read the entire instruction manual before starting the

installation.

This symbol → indicates a change since the last issue.

Index Page

SAFETY CONSIDERATIONS .....................................................1

ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS

PROCEDURE ...........................................................................2

INTRODUCTION.......................................................................3-4

Dimensional Drawing ...............................................................2

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................................................................................5-6

General Requirements...............................................................5

Ductwork Acoustical Treatment...............................................5

Supply-Air Connections............................................................6

Return-Air Connections............................................................6

DOWNFLOW INSTALLATION..................................................7

HORIZONTAL ATTIC INSTALLATION...................................9

Construct a Working Platform .................................................9

Install Furnace...........................................................................9

HORIZONTAL CRAWLSPACE INSTALLATION....................9

FILTER ARRANGEMENT...........................................................9

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

ELECTRICAL CONNECTIONS...........................................10-12

115-v Wiring...........................................................................10

24-v Wiring.............................................................................11

Accessories ........................................................................11-12

VENTING ....................................................................................12

START-UP, ADJUSTMENT, AND SAFETY CHECK.......12-21

General ....................................................................................12

Sequence Of Operation...........................................................13

Heating Mode..........................................................................12

Cooling Mode .........................................................................15

Continuous Blower Mode.......................................................15

Heat Pump Mode....................................................................15

Start-up Procedures.................................................................15

Adjustments .......................................................................15-21

Set Gas Input Rate..................................................................15

Set Temperature Rise..............................................................19

Set Thermostat Heat Anticipator............................................20

Check Safety Controls............................................................20

Checklist..................................................................................21

REGISTERED QUALITY SYSTEM

SAFETY CONSIDERATIONS

Installing and servicing heating equipment can be hazardous due to
gas and electrical components. Only trained and qualified person­nel 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
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 54-1999/ANSI Z223.1-1999 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 furnace 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.

ama

58ZAV

CERTIFIED

®

.

Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

Book 1 4
Tab 6a 8a

PC 101 Catalog No. 535-768 Printed in U.S.A. Form 58ZAV-12SI Pg 1 10-00 Replaces: 58ZAV-10SI

1

28

⁄2″

20″

13

⁄16″

7

39

⁄8″

11

⁄16″

INLET

7

⁄8″ DIA

ACCESSORY

3

1

⁄4″ DIA HOLE

GAS ENTRY

OUTLET

19″

NOTE:

ADDITIONAL
LOCATED IN THE TOP PLATE
AND BOTTOM PLATE

7

⁄8″ DIA K.O.’s ARE

VENT CONNECTION

13

⁄16″

1

9

⁄8″

1

10

⁄4″

1

1

⁄16″

1

2

⁄8″

1

8

⁄4″

11

⁄16″

AIRFLOW

D

E

A

DIMPLES TO DRILL HOLES
FOR HANGER BOLTS (4 PLACES)
IN HORIZONTAL POSITION

16

11

1

13

⁄16″

4

2

⁄16″

3

5

⁄16″

15

⁄16″

10

⁄16″

1

⁄4″

1

⁄2″ DIA

2″

THERMOSTAT
WIRE ENTRY

7

⁄8″ DIA

ACCESSORY

7

⁄8″ DIA HOLE

POWER ENTRY

1

1

⁄2″ DIA

R.H. GAS ENTRY

7

⁄8″ DIA

ACCESSORY

1

1

⁄16″

1

2

⁄8″

″ TYP

1

5

⁄8″ TYP

NOTE:

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 14
b. For 1200 CFM–20-in. round or 14
c. For 1600 CFM–22-in. round or 14
d. For airflow requirements above 1800 CFM, must use entire return air opening.

1

⁄2 x 12-in. rectangle.

1

⁄2 x 191⁄2-in. rectangle.

1

⁄2 x 231⁄4-in. rectangle.

Fig. 1—Dimensional Drawing

Table 1—Dimensions (In.)

UNIT SIZE A D E VENT CONN SHIP. WT (LB)

050-08 14-3/16 12-9/16 12-11/16 4 124
050-12 14-3/16 12-9/16 12-11/16 4 128
070-08 14-3/16 12-9/16 12-11/16 4 129
070-12 14-3/16 12-9/16 12-11/16 4 137
096-12 17-1/2 15-7/8 16 4 146
096-16 17-1/2 15-7/8 16 4 151
115-16 17-1/2 15-7/8 16 4 159
115-20 21 19-3/8 19-1/2 4 174
115-22 21 19-3/8 19-1/2 4 176
135-20 24-1/2 22-7/8 23 5 193

ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS

PROCEDURE

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

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.

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.

2

A99288

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
mat er ial.

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
install ed 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.

18 inches front clearance required for alcove.

Ø

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.

##

ForTypeB-1venttype3inches.

††

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

Fig. 2—Clearances to Combustibles

This furnace is approved for DOWNFLOW and HORIZONTAL
installations.

Clearance arrows
do not change with
furnace orientation.

0"

†

†

B

A

C

K

E

D

I

S

1" #

*

Clearance in inches

1"

TOP / PLENUM

E

C

A

N

R

U

F

1

†

T

N

O

R

F

F

R

BOTTOM

#

"

S

O

N

T

##

Ø

1"

#

E

*

D

I

S

E

R

V

I

C

E

30"

Vent Clearance to combustibles:

For Single Wall vents 6 inches.
For Type B-1 vent type 1 inch .

322286-101 REV. F (LIT)

MIN

A99262

INTRODUCTION

The model 58ZAV Series 151 and 161 Furnaces are available in
sizes 46,000 through 135,000 Btuh input capacities.

The design of the downflow/horizontal gas-fired furnace is CSA
(A.G.A. and 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 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 CSA (A.G.A. and C.G.A.) certified for
installation in mobile homes, recreation vehicles, or outdoors.

Before installing the furnace in the United States, refer to the
current edition of the NFGC and the NFPA 90B. For further
information, the NFGC and NFPA 90B are available from Na­tional Fire Protection Association Inc., Batterymarch Park,
Quincy, MA 02269; or the American Gas Association, 400 N.
Capitol St., NW, Washington DC 20001.

Before installing the furnace in Canada, refer to the current edition
of 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.

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.

NOTE: These furnaces are designed for a minimum continuous
return-air temperature of 60°F or intermittent operation down to
55°F such as when used with a night setback thermostat. Return-air
temperature must not exceed a maximum of 85°F. Failure to
follow these return-air temperature limits may affect reliability of
heat exchangers, motors, and controls.

3

A93042

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.

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.

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.

HAZARDOUS LOCATIONS

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

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

Step 1—Location

GENERAL

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.
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.

18-IN. (457.2 mm)

MINIMUM TO BURNERS

A93044

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.

Step 2—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.

DO NOT install the furnace on its back; safety control
operation will be adversely affected. Failure to follow this
warning could result in fire, personal injury, or death.

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

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.

4

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.

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

For Example:

58ZAV FURNACE

INPUT BTUH

46,000 307
69,000 460

92,000 613
115,000 767
135,000 920

MINIMUM SQ FT

WITH

7-1/2 FT CEILING

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.

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 hori-

zontal 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 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

Step 1—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 supply- and return-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.

Step 2—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.

5

VENT THROUGH ROOF
(CATEGORY I)

DUCTS TO

OUTDOORS

1 SQ IN.
PER 4000
BTUH

*

RETURN

AIR

INTERIOR

HEATED

SPACE

SUPPLY AIR

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

†

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

12″ MAX

1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL

UNCONFINED
SPACE

6″ MIN
(FRONT)

1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL

†

12″ MAX

A93387

Fig. 3—Confined Space: Air for Combustion and

Ventilation from an Unconfined Indoor Space

12″ MAX

1 SQ IN.
PER 2000
BTUH

*

DUCTS

TO

OUTSIDE

1 SQ IN.
PER 2000
BTUH

*

12″ MAX

SUPPLY AIR

Minimum dimensions of 3 in.

*

Use any of the following

NOTE:

combinations of openings:
A & B C & D D & E F & G

RETURN

A

B

AIR

D

VENT
THROUGH
ROOF
(CATEGORY I)

CONFINED

C

DUCT

TO

OUTDOORS

F

SPACE

G

E

12″ MAX

12

″

MAX

1 SQ IN.
PER 4000
BTUH

OUTDOORS

1 SQ IN.
PER 4000
BTUH

12

″

MAX

1 SQ IN.
PER 4000
BTUH

*

*

A93388

Fig. 4—Confined Space: Air for Combustion and

Ventilation from Outdoors

Table 2—Minimum Free Area Of Combustion Air Opening

AIR FROM UNCON-

58ZAV

FURNACE

INPUT

(BTUH)

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 connectors in the confined space. Opening area must be increased if other gas appliances
in the space require combustion air.

FINED INDOOR

SPACE

Free Area

of Opening

(Sq In.)

Step 3—Supply Air Connections

DOWNFLOW FURNACES

Connect supply-air duct to supply-air opening on furnace. 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.

HORIZONTAL FURNACES

Connect supply-air duct to supply air opening on furnace. The
supply-air duct attachment must ONLY be connected to furnace

OUTDOOR AIR THROUGH

VERTICAL DUCTS

Free Area of

Opening and Duct

(Sq In.)

Round

Pipe

(In. Dia)

OUTDOOR AIR THROUGH

HORIZONTAL DUCTS

Free Area of

Opening and Duct

(Sq In.)

Round

Pipe

(In. Dia)

OUTDOOR AIR THROUGH

SINGLE DUCT

Free Area of

Opening and Duct

(Sq In.)

Round

Pipe

(In. Dia)

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.

Step 4—Return Air Connections

The return-air duct must be connected to return-air opening
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.

6

FURNACE

CASING

WIDTH

14-3/16

17-1/2

21

24-1/2

A

PLENUM

OPENING

B

OPENING

D

FLOOR

C

Fig. 5—Floor and Plenum Opening Dimensions

Table 3—Opening Dimensions (In.)

APPLICATION

Non-Combustible Flooring 12-11/16 19 13-3/8 19-5/8

Combustible Flooring Using KGASB Subbase 11-13/16 19 13-7/16 20-3/8

Combustible Flooring with CD5 or CK5 Coil Assembly or

KCAKC Coil Box

Non-Combustible Flooring 16 19 16-5/8 19-5/8

Combustible Flooring Using KGASB Subbase 15-1/8 19 16-3/4 20-3/8

Combustible Flooring with CD5 or CK5 Coil Assembly or

KCAKC Coil Box

Non-Combustible Flooring 19-1/2 19 20-1/8 19-5/8

Combustible Flooring Using KGASB Subbase 18-5/8 19 20-1/4 20-3/8

Combustible Flooring with CD5 or CK5 Coil Assembly or

KCAKC Coil Box

Non-Combustible Flooring 23 19 23-5/8 19-5/8

Combustible Flooring Using KGASB Subbase 22-1/8 19 23-3/4 20-3/8

Combustible Flooring with CD5 or CK5 Coil Assembly or

KCAKC Coil Box

PLENUM OPENING FLOOR OPENING

ABCD

12-5/16 19 13-5/16 20

15-1/2 19 16-1/2 20

19 19 20 20

22-1/2 19 23-1/2 20

A96283

FRONT

BACK

FRONT

→

Do not install furnace on its back. Safety control operation
will be adversely affected. Never connect return-air ducts to
back of furnace. Failure to follow this warning could result in
fire, personal injury, or death.

B
A
C
K

Step 5—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.

1. Determine application being installed from Table 3.

A93043

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

3. Construct plenum to dimensions specified in Table 3.

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

7

FURNACE

(OR COIL CASING

WHEN USED)

FURNACE

CD5 OR CK5

COIL ASSEMBLY

OR KCAKC

COIL BOX

COMBUSTIBLE

FLOORING

DOWNFLOW

SUBBASE

SHEET METAL

PLENUM

FLOOR

OPENING

A96285

Fig. 6—Furnace, Plenum, and Subbase Installed

on a Combustible Floor

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.

COMBUSTIBLE

FLOORING

SHEET METAL

PLENUM

FLOOR

OPENING

A96284

Fig. 7—Furnace, Plenum, and Coil Assembly or

Coil Box Installed on a Combustible Floor

MANUAL SHUTOFF

GAS VALVE

SEDIMENT

TRAP

GAS
ENTRY

6

24

24

″

″

SHEET
METAL

Fig. 8—Typical Attic Installation

8

″

MIN

TYPE-B
VENT

30-IN. MIN
WORK AREA

A97516