Bryant 312AAV User Manual
Installation, Start-up,
and Operating Instructions
2-SPEED, 2-STAGE INDUCED COMBUSTION
DELUXE 4-WAY MULTIPOISE FURNACE
NOTE: Read the entire instruction manual before starting the
installation.
312AAV
Series
100
Cancels: New II 312A-91–1
11–00
TABLE OF CONTENTS
Safety Considerations.....................................................................1
Introduction ....................................................................................1
Codes and Standards......................................................................4
Safety.........................................................................................4
General Installation...................................................................4
Combustion and Ventilation Air ..............................................4
Duct Systems ............................................................................4
Acoustical Lining and Fibrous Glass Duct..............................4
Gas Piping and Gas Pipe Pressure Testing..............................4
Electrical Connections ..............................................................4
Electrostatic Discharge (ESD) Precautions Procedure..................4
Applications....................................................................................5
General ......................................................................................5
Uplflow Applications................................................................5
Downflow Applications............................................................5
Horizontal Left (Supply-Air Discharge) Applications ............5
Horizontal Right (Supply-Air Discharge) Applications ..........5
Location..........................................................................................5
General ......................................................................................5
Location Relative to Cooling Equipment ................................5
Air for Combustion and Ventilation..............................................6
Unconfined Space .....................................................................6
Confined Space .........................................................................6
Air Ducts...................................................................................7
Installation ......................................................................................8
Leveling Legs (If Desired) .......................................................8
Bottom Closure Panel...............................................................8
Downflow Installation ..............................................................8
Horizontal Attic Installation .....................................................9
Installation in Horizontal Crawlspace Applications ................9
Media Cabinet (PN 325887–701) and Filter Arrangement.....9
Gas Piping.................................................................................9
Electrical Connections ............................................................12
Start-Up, Adjustment, and Safety Check ....................................14
General ....................................................................................14
Sequence of Operation............................................................14
Start-Up Procedures................................................................20
Adjustments.............................................................................23
Check Safety Controls............................................................27
Checklist..................................................................................28
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.
Observe precautions in the literature, on tags, and on labels
attached to or shipped with the unit and other safety precautions
that may apply.
CERTIFIED
REGISTERED QUALITY SYSTEM
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.
Wear safety glasses and work gloves. Have fire extinguisher
available during start-up and adjustment procedures and service
calls.
This is the safety alert symbol
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.
INTRODUCTION
The 312AAV, Series 100 (limited) 4–way multipoise Category I
furnace is CSA (A.G.A. and C.G.A.) design-certified for natural
and propane gas and for installation in alcoves, attics, basements,
closets, utility rooms, crawlspaces, and garages. The furnace is
factory-shipped for use with natural gas. A CSA (A.G.A. and
C.G.A.) listed gas conversion kit is required to convert furnace for
use with propane gas. This furnace is not approved for installation
in mobile homes, recreational vehicles, or outdoors.
These furnaces shall not be installed directly on carpeting, tile, or
any other combustible material other than wood flooring. For
downflow installations, a factory accessory floor base must be
used when installed on combustible materials and wood flooring.
This special base is not required when this furnace is installed on
the manufacturer’s coil assembly, or when the manufacturer’s coil
box is used.
®
. When you see this symbol on
—1—
(Optional)
*
(Optional)
x 12-in. rectangle.
/2
1
/2-in. rectangle.
1
/2 x 19
1
A00264
(Optional)
-in. dia holes are located in the top plate.
/8
7
see flex duct manufacturer’s recommendations for equivalent diameters.
a. For 800 CFM–16-in. round or 14
2. Minimum return-air openings at furnace, based on metal duct. If flex duct is used,
3. Minimum return-air opening at furnace:
NOTES: 1. Two additional
Fig. 1–Dimensional Drawing
b. For 1200 CFM–20-in. round or 14
* In upflow, one optional vent is located on the bottom of the outer door.
—2—
INSTALLATION
MINIMUM INCHES CLEARANCE TO COMBUSTIBLE CONSTRUCTION
DISTANCE MINIMALE EN POUCES AUX CONSTRUCTIONS COMBUSTIBLES
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
This furnace is approved for UPFLOW, DOWNFLOW, and
HORIZONTAL installations.
Cette fournaise est approuvée pour l´installation HORIZONTALE et
la circulation d´ai r VERS LE HAUT, VERS LE BAS.
Clearance arrows
do not change with
furnace orientation.
*
Les fléches de dégagement
ne changent pas avec
l´orientation de la fournaise.
0"
§
flooring in alcove or closet at minimum clearance
as indicated by the diagram 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.
Cette fournaise à air pulsé est équipée
pour utilisation avec gaz naturel et altitudes
comprises entre 0-3,050m (0-10,000 pi).
Utiliser une trousse de conversion, fournie par
le fabricant, pour passer au gaz propane ou pour
certaines installations au gaz naturel.
Cette fournaise est prévue pour être
installée dans un bâtiment construit sur place.
Cette fournaise peut être installée sur
un plancher combustible dans une alcôve ou
0"
§
B
A
A
C
R
K
R
I
È
R
E
E
D
I
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0"
*
#
TOP
DESSUS
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C
A
S
I
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A
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F
R
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F
T
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3"
##
Ø
dans un garde-robe en respectant le minimum
d'espace libre des matériaux combustibles, tel
qu'indiqué sur le diagramme.
Cette fournaise peut être utilisée avec un
conduit d´évacuation de Type B-1 ou connectée
Clearance in inches
Dégagement (po).
0"
BOTTOM
DESSOUS
†
#
au conduit commun d´autres appareils à gaz..
MINIMUM INCHES CLEARANCE TO COMBUSTIBLE CONSTRUCTION
ALL POSITIONS:
Vent Clearance to combustibles: For Single Wall vents 6 inches (6 po). For Type B-1 vent type 1 inch (1 po).
#
For single wall vent type 6 inches. For type B-1 vent type 3 inches.
#
#
Ø
18 inches front clearance required for alcove.
1 inch clearance required from combustibles to supply plenum.
*
DOWNFLOW POSITIONS:
For installation on combustible floors only when installed on special base No. KGASB0201ALL, Coil Assembly,
†
Part No. CD5 or CK5, or Coil Casing, Part No. KCAKC.
HORIZONTAL POSITIONS:
Line contact is permissible only between lines formed by intersections of top and back of furnace jacket, and
§
building joists, studs, or framing.
DÉGAGEMENT MINIMUM EN POUCES AVEC ÉLÉMENTS DE
CONSTRUCTION COMBUSTIBLES
POUR TOUS LES POSITIONS:
Dégagement de l' évent avec combustibles: Pour conduit d'évacuation à paroi simple 6 po (6 inches).
#
Pour conduit d'évacuation de Type B-1 1 po (1 inch).
#
Pour conduit d'évacuation à paroi simple 6 po (6 inches).
#
Dans une alcôve, on doit maintenir un dégagement à l'avant de 18 po (450mm).
Ø
Un pouce d'espace libre nécessaire entre les matériaux combustibles et le plenum d'alimentation.
*
POUR LA POSITION COURANT DESCENDANT:
Pour l'installation sur le plancher combustible seulement quand on utilis la base spéciale, piéce n° KGASB0201ALL,
†
l' ensemble serpentin, piéce n° CD5 ou CK5, ou le carter de serpentin, piéce n° KCAKC.
POUR LA POSITION HORIZONTALE:
Le contact avec les conduites de gaz est seulement permis aux intersections des conduites formées par le dessus
§
et l'arriére de l'enveloppe de la fournaise et les solives, les montants ou le cadrage de l'édifice.
Pour conduit d'évacuation de Type B-1 3 po (3 inches).
326379-101 REV. A (lit-bottom)
0"
#
*
È
V
I
C
E
T
I
E
N
30"
MIN
Fig. 2–Clearances to Combustibles
—3—
A00287
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 may require excessive servicing or cause premature component
failure.
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 or
property damage. Consult a qualified installer, service
agency, local gas supplier, or your distributor or branch
for information and 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.
This furnace is designed for minimum continuous return-air
temperature of 60°F db or intermittent operation down to 55°F db.
Return-air temperature must not exceed 85°Fdb. (See Fig. 3.)
II. GENERAL INSTALLATION
• US: Current edition of the NFGC and the NFPA 90B. For
copies, 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, N.W.,
Washington DC 20001
• CANADA: NSCNGPIC. For a copy, contact Standard Sales,
CSA International, 178 Rexdale Boulevard, Etobicoke (Toronto), Ontario, M9W 1R3 Canada
III. COMBUSTION AND VENTILATION AIR
• US: Section 5.3 of the NFGC, Air for Combustion and
Ventilation
• CANADA: Part 7 of NSCNGPIC, Venting Systems and Air
Supply for Appliances
IV. DUCT SYSTEMS
• US and CANADA: Air Conditioning Contractors Association
(ACCA) Manual D, Sheet Metal and Air Conditioning Contractors National Association (SMACNA), or American Society of Heating, Refrigeration, and Air Conditioning Engineers
(ASHRAE) 1997 Fundamentals Handbook Chapter 32.
V. ACOUSTICAL LINING AND FIBROUS GLASS DUCT
• US and CANADA: current edition of SMACNA and NFPA
90B as tested by UL Standard 181 for Class I Rigid Air Ducts
VI. GAS PIPING AND GAS PIPE PRESSURE TESTING
• US: NFGC; chapters 2,3,4, and 9 and National Plumbing Codes
• CANADA: NSCNGPIC Part 5
VII. ELECTRICAL CONNECTIONS
• US: National Electrical Code (NEC) ANSI/NFPA 70–1999
• CANADA: Canadian Electrical Code CSA C22.1
A93042
Fig. 3–Return Air Temperature
For accessory installation details, refer to the applicable instruction
literature.
NOTE: Remove all shipping brackets and materials before operating the furnace.
CODES AND STANDARDS
Follow all national and local codes and standards in addition to
these instructions. The installation must comply with regulations
of the serving gas supplier, local building, heating, plumbing, and
other codes. In absence of local codes, the installation must
comply with the national codes listed below and all authorities
having jurisdiction.
In the United States and Canada, follow all codes and standards for
the following:
I. SAFETY
• US: National Fuel Gas Code (NFGC) NFPA 54–1999/ANSI
Z223.1–1999 and the Installation Standards, Warm Air Heating
and Air Conditioning Systems ANSI/NFPA 90B
• CANADA: CAN/CGA-B149.1–and .2–M95 National Standard
of Canada. Natural Gas and Propane Installation Codes (NSCNGPIC)
ELECTROSTATIC DISCHARGE (ESD) PRECAUTIONS
PROCEDURE
Use this procedure for all installed and uninstalled furnaces. An
ESD service kit (available from commercial sources) may be used
to prevent ESD damage.
CAUTION: Electrostatic discharge can affect electronic
components. Follow the Electrostatic Discharge Precautions Procedure listed below 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. Multiple disconnects
may be required. DO NOT TOUCH THE CONTROL OR
ANY WIRE CONNECTED TO THE CONTROL PRIOR
TO DISCHARGING YOUR BODY’S CHARGE TO
GROUND.
2. Firmly touch a clean, unpainted metal surface on the
furnace chassis close to the control. Tools held in hand
during grounding will be discharged.
3. You may proceed to service the control or connecting wires
as long as you do nothing to recharge your body (moving or
shuffling feet, touching ungrounded objects, etc.)
4. If you touch ungrounded objects, firmly touch a clean,
unpainted metal surface again before touching control or
wires.
—4—
AIRFLOW
UPFLOW
HORIZONTAL
LEFT
AIRFLOW
Fig. 4–Multipoise Orientations
5. Before removing a new control from it’s container, discharge your body’s charge to the ground. If the control is to
be installed in a furnace, follow items 1 through 4 before
bringing the control or yourself in contact with the furnace.
Put all used and new controls into containers before
touching ungrounded objects.
APPLICATIONS
I. GENERAL
This multipoise furnace is shipped in packaged configuration.
Some assembly and modifications are required when used in any
of the four applications shown in Fig. 4.
II. UPLFLOW APPLICATIONS
In an upflow application, the blower is located below the burner
section, and conditioned air is discharged upward.
III. DOWNFLOW APPLICATIONS
In a downflow application, the blower is located above the burner
section, and conditioned air is discharged downward.
IV. HORIZONTAL LEFT (SUPPLY-AIR DISCHARGE) APPLICATIONS
In a horizontal left application, the blower is located to the right of
the burner section, and conditioned air is discharged to the left.
V. HORIZONTAL RIGHT (SUPPLY-AIR DISCHARGE)
APPLICATIONS
In a horizontal right application, the blower is located to the left of
the burner section, and conditioned air is discharged to the right.
LOCATION
I. GENERAL
This furnace must:
• be installed so the electrical components are protected from
water.
• not be installed directly on any combustible material other than
wood flooring (refer to INTRODUCTION).
• be located as close to the chimney/vent and attached to an air
distribution system. Refer to Air Ducts section.
• be provided ample space for servicing and cleaning. Always
comply with minimum fire protection clearances shown on the
furnace rating plate.
DOWNFLOW
AIRFLOW
HORIZONTAL
RIGHT
AIRFLOW
A93041
CAUTION: Do not install furnace in a corrosive or
contaminated atmosphere. Make sure all combustion and
circulating air requirements are met, in addition to all
local codes and ordinances.
CAUTION: Do not operate the furnace during construction. If the furnace is required, use clean outside air free
of chlorine and fluorine compounds for combustion and
ventilation. These compounds form acids that corrode the
heat exchangers and vent system. These compounds are
found in paneling and dry wall adhesives, paints, thinners, masonry cleaning materials, and other solvents.
WARNING: DO NOT install the furnace on its back.
Safety control operation will not perform properly. A
failure to follow this warning can cause a fire, personal
injury, or death.
II. LOCATION RELATIVE TO COOLING EQUIPMENT
FRONT
B
A
C
K
BACK
FRONT
A93043
Fig. 5–Prohibit Installation on Back
The cooling coil must be installed parallel with, or on the
downstream side of the unit to avoid condensation in the heat
exchangers. When installed parallel with the furnace, dampers or
—5—
other flow control must prevent chilled air from entering the
furnace. 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.
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 Part 7 and all authorities having jurisdiction.
WARNING: When the furnace is installed in a residential garage, the burners and ignition sources must be
located at least 18 inches above the floor. The furnace
must be located or protected to avoid damage by vehicles.
When the furnace is installed in a public garage, airplane
hangar, or other building having a hazardous atmosphere,
the furnace must be installed in accordance with the
National Fire Protection Association, Inc. requirements.
18-IN. (457.2 mm)
MINIMUM TO BURNERS
A93044
Fig. 6–Location to Burners
CAUTION: Air for combustion must not be contami-
nated 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.
All fuel-burning equipment must be supplied with air for fuel
combustion. Sufficient air must be provided to avoid negative
pressure in the equipment room or space. A positive seal must be
made between the furnace cabinet and the return-air duct to
prevent pulling air from the burner area and from blocked vent
safeguard opening.
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.
The requirements for combustion and ventilation air depend upon
whether the furnace is located in an unconfined or confined space.
I. UNCONFINED SPACE
An unconfined space has a volume of at least 50 cu ft for each
1000 Btuh total input for all appliances (furnaces, clothes dryers,
water heaters, etc.) in the space.
For example:
TABLE 1–312AAV FLOOR AREA
312AAV FURNACE
INPUT (BTUH)
88,000 587
MINIMUM WITH
7–1/2 FT CEILING (SQ. FT.)
If the unconfined space is constructed unusually tight, air for
combustion and ventilation must come from either the outdoors or
spaces freely communicating with the outdoors. Combustion and
ventilation openings must be equivalent to those used for a
confined space (defined below). Return air must not be taken from
the room unless an equal or greater amount of air is supplied to the
room.
II. CONFINED SPACE
A confined space has a volume 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 in Table 2 and Fig. 7and 8.
NOTE: When determining the free area of an opening, the
blocking effect of louvers, grilles, and screens must be considered.
If the free area of the louver or grille design is unknown, assume
wood louvers have a 20 percent free area and metal louvers or
grilles have a 60 percent free area. Screens must not be smaller
than 1/4-in. mesh. Louvers and grilles must be constructed so they
cannot be closed.
The opening size depends upon whether air comes from outside of
the structure or an unconfined space inside the structure.
1. Air from inside the structure requires 2 openings (for
structures not of unusually tight construction):
a. Each opening must have a minimum free area of not less
than 1 sq in per 1000 Btuh of total input rating for all gas
utilization equipment in the confined space, but not less
than 100 sq in. The minimum dimension of air openings
should be no smaller than 3 in. (See Table 2 and Fig. 7
and 8).
b. If building construction is unusually tight, a permanent
opening directly communicating with the outdoors shall
be provided. (See next section).
c. If the furnace is installed on a raised platform to provide
a return-air plenum, and return air is taken directly from
the 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:
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. 8 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. 8 and
Table 2.)
c. If combustion air is taken from the outdoors through a
single opening or duct (horizontal or vertical) commencing within 12 in. of the top of the confined space, the
opening and duct must have at least 1 sq in. of free area
—6—
SUPPLY
AIR
VENT THROUGH ROOF
DUCTS
TO
OUTDOORS
1 SQ IN.
PER 4000
*
BTUH
12″ MAX
1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL
INTERIOR
HEATED
SPACE
RETURN AIR
* Minimum opening size is 100 sq in. with
minimum dimensions of 3 in.
†
Minimum of 3 in. when type-B1 vent is used.
Fig. 7–Confined Space: Air for Combustion and Ventilation
UNCONFINED
SPACE
CONFINED
SPACE
6″ MIN
(FRONT)
1 SQ IN.
PER 1000
BTUH* IN DOOR
OR WALL
†
12″ MAX
A89012
from an Unconfined Indoor Space
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. 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.
See Table 2 and Fig. 8.
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.
III. AIR DUCTS
A. 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 The Air Systems Design Guide-
lines reference tables available from your local distributor. The
duct system should be sized to handle the required system design
CFM at the design external 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.
12″ MAX
1 SQ IN.
PER 2000
*
BTUH
DUCTS
TO
OUTDOORS
1 SQ IN.
PER 2000
*
BTUH
″ MAX
12
RETURN AIR
*Minimum dimensions of 3 in.
Use any of the following
NOTE:
combinations of openings:
A & B C & D D & E F & G
A
SUPPLY
AIR
B
Fig. 8–Confined Space: Air for Combustion and Ventilation
D
VENT
THROUGH
ROOF
CONFINED
C
DUCT
TO
OUTDOORS
SPACE
E
12″ MAX
F
1 SQ IN.
PER
4000
BTUH*
1 SQ IN.
PER
4000
BTUH*
G
1 SQ IN.
PER 4000
*
BTUH
A89013
12″
MAX
OUTDOORS
12″
MAX
from Outdoors
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.
B. 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.
C. Supply Air Connections
UPFLOW FURNACES
Connect supply-air duct to 3/4-in. flange on furnace supply-air
outlet. Bend flange upward to 90° with wide duct pliers. The
supply-air duct attachment must ONLY be connected to furnace
supply-/outlet-air duct flanges 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. Supply air
opening duct flanges must be modified per Fig. 14.
—7—
TABLE 2–MINIMUM FREE AREA OF COMBUSTION AIR OPENING*
312AAV
FURNACE
INPUT
(BTUH)
88,000 100 22.0 6 44.0 8 29.33 7
* 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.
AIR FROM INDOOR
UNCONFINED SPACE
Free Area
of Opening
(Sq In.)
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)
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 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 casing. Supply
air opening duct flanges must be modified per Fig. 14.
HORIZONTAL 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). DO NOT
cut main furnace casing to attach supply side air duct, humidifier,
or other accessories. All accessories MUST be connected external
to furnace casing. Supply air opening duct flanges must be
modified per Fig. 14.
D. Return Air Connections
DOWNFLOW AND HORIZONTAL FURNACES
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.
The return-air duct must be connected to return-air opening
(bottom inlet) as shown in Fig. 1. DO NOT cut into casing sides
(left or right). Side opening is permitted for only upflow furnaces.
Bypass humidifier connections should be made at ductwork or coil
casing sides exterior to furnace.
UPFLOW FURNACES
The return-air duct must be connected to bottom, sides (left or
right), or a combination of bottom and side(s) of main furnace
casing as shown in Fig. 1. Bypass humidifier may be attached into
unused side return air portion of the furnace casing.
INSTALLATION
I. LEVELING LEGS (IF DESIRED)
When furnace is used in upflow position with side inlet(s), leveling
legs may be desired. (See Fig. 9.) Install field-supplied, corrosionresistant 5/16-in. machine bolts and nuts.
NOTE: The maximum length of bolt should not exceed 1-1/2 in.
1. Position furnace on its back. Locate and drill a 5/16-in.
diameter hole in each bottom corner of furnace. (See Fig.
9.) Holes in bottom closure panel may be used as guide
locations.
2. For each hole, install nut on bolt and then install bolt and
nut in hole. (Install flat washer if desired.)
3. Install another nut on other side of furnace base. (Install flat
washer if desired.)
4. Adjust outside nut to provide desired height, and tighten
inside nut to secure arrangement.
5/
16″
(8mm)
(8mm)
5/
16″
1 3/ 4″
(44mm)
3
/ 4″
1
(44mm)
(8mm)
5
/ 16″
(8mm)
5/
16″
(44mm)
1 3/ 4″
1 3/ 4″
(44mm)
A89014
Fig. 9–Leveling Legs
NOTE: Bottom closure must be used when leveling legs are used.
NOTE: Remove and discard bottom closure panel when bottom
inlet is used.
II. BOTTOM CLOSURE PANEL
These furnaces are shipped with bottom closure panel installed in
bottom return-air opening. This panel MUST be in place when side
return air is used.
To remove bottom closure panel, perform the following:
1. Tilt or raise furnace and remove 2 screws holding front
filler panel. See Fig. 10)
2. Rotate front filler panel downward to release holding tabs.
3. Remove bottom closure panel.
4. Reinstall front filler panel and screws.
NOTE: Side return-air openings can ONLY be used in UPFLOW
configurations.
III. DOWNFLOW INSTALLATION
NOTE: For downflow applications, this furnace is approved for
use on combustible flooring when special base (Part No.
KGASB0201ALL) is used. Special 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.
2. Construct hole in floor per dimensions specified in Table 3
and Fig. 11.
3. Construct plenum to dimensions specified in Table 3 and
Fig. 11.
4. If downflow subbase (KGASB) is used, install as shown in
Fig. 12.
—8—
BOTTOM
CLOSURE
PAN EL
FRONT FILLER
PANEL
A93047
Fig. 10–Removing Bottom Closure Panel
If Coil Assembly Part No. CD5 or CK5 or Coil Box Part No.
KCAKC is used, install as shown in Fig. 13.
NOTE: Remove the furnace perforated supply-air duct flanges
when they interfere with mating flanges on the coil on downflow
subbase. To remove the supply-air duct flange, use wide duct
pliers or duct flange tool to bend flange back and forth until it
breaks off. Be careful of sharp edges. (See Fig. 14.)
Fig. 16). Furnace can be suspended from each corner by hanger
bolts and angle iron supports. (See Fig. 15.) Cut hanger bolts (4
each 3/8-in. all-thread rod) to desired length. Use 1 X 3/8-in. flat
washers, 3/8-in. lockwashers, and 3/8-in. nuts on hanger rods as
shown in Fig. 15.
CAUTION: The entire length of the furnace MUST be
supported when furnace is used in a horizontal position.
When suspended, bottom brace supports sides and center
blower shelf. When unit is supported from the ground,
blocks or pad should support sides and center blower
shelf area.
VI. MEDIA CABINET (PN 325887–701) AND FILTER ARRANGEMENT
Center media cabinet on furnace return-air inlet. If flush fit
required with media cabinet to back of furnace casing, a field
supplied patch plate is required to seal gap at front edge of furnace
and media cabinet. Insert filter (supplied with furnace) into media
cabinet.
WARNING: Never operate a furnace without a filter or
with filter access door removed. Failure to follow this
warning could result in fire, personal injury, or death.
WARNING: Do not bend duct flanges inward. This will
affect airflow across heat exchangers and may cause limit
cycling or premature heat exchanger failure. Remove
duct flange completely or bend it inward a minimum of
210° as shown in Fig. 14.
IV. 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.
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. 17.
A. Construct a Working Platform
Construct working platform on location where all required furnace
clearances are met. (See Fig. 2 and 17.)
B. Install Furnace
1. Position furnace in desired location.
2. Connect gas supply pipe. See Fig. 17 for typical piping
entry.
3. Connect supply- and return-air ducts with filter media
cabinet per Step 6.
4. Install 24- X 24-in. sheet metal shield on platform in front
of louvered control panel as shown in Fig. 17.
V. INSTALLATION IN HORIZONTAL CRAWLSPACE APPLICATIONS
These furnaces can be installed horizontally in either horizontal
left or right discharge position. In a crawlspace, furnace can either
be hung from floor joist or installed on suitable blocks or pad. (See
VII. GAS PIPING
Gas piping must be installed in accordance with national and local
codes. Refer to current edition of NFGC in the U.S.
Canadian installations must be made in accordance with NSCNGPIC and all authorities having jurisdiction.
Gas supply line should be a separate line running directly from
meter to furnace, if possible.
Refer to Table 5 for recommended gas pipe sizing. Risers must be
used to connect to furnace and to meter. Support all gas piping
with appropriate straps, hangers, etc. Use a minimum of 1 hanger
every 6 ft. Joint compound (pipe dope) should be applied sparingly
and only to male threads of joints. Pipe dope must be resistant to
the action of propane gas.
CAUTION: If a flexible connector is required or allowed by the authority having jurisdiction, black iron
pipe shall be installed at the gas valve and extend a
minimum of 2 in. outside the furnace casing.
CAUTION: Connect gas pipe to furnace using a backup
wrench to avoid damaging gas controls.
WARNING: Never purge a gas line into a combustion
chamber. Never use matches, candles, flame, or other
sources of ignition for purpose of checking leakage. Use
a soap-and-water solution to check for leakage. A failure
to follow this warning could result in fire, explosion,
personal injury, or death.
—9—
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