Williams AC2030 User manual

OWNER’S MANUAL
MODEL NUMBERS:
AC2030TN FOR USE WITH NATURAL GAS ONLY
READ THIS OWNER’S MANUAL CAREFULLY BEFORE
YOU INSTALL YOUR NEW WILLIAMS WALL FURNACE.
WARNING: If the information in these instructions
is not followed exactly, a fire or explosion may result
causing property damage, personal injury or loss of life.
Do not store or use gasoline or other flammable vapors
and liquids in the vicinity of this or any other appliance.
WHAT TO DO IF YOU SMELL GAS:
• Open all windows.
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use
any phone or cell phone in your building.
• Extinguish any open flame.
• Immediately call your gas supplier from a neighbor’s
phone. Follow the gas supplier’s instructions.
• If you cannot reach the gas supplier, call the fire
department.
Installation and service must be performed by a qualified
installer, service agency or the gas supplier.
WARNING: Improper installation, adjustment, alteration,
service or maintenance can cause injury or property
damage. Refer to this manual. For assistance or for
additional information consult a qualified installer,
service agency or the gas supplier.
WWW.WFC-FC.COM • 888-444-1212
20,000 - 30,000 BTU/hr. Model
AC2030
TOP-VENT GAS WALL HEATER
Save this manual for future reference
WARNING: INSTALLATION IN MANUFACTURED HOMES
Williams Top-Vent Furnaces are allowed in manufactured
homes when the following conditions are met:
-The manufactured home is permanently sited per local codes.
-The manufactured home is manufactured after 6/15/1976
and is HUD approved with a red certification label (US only).
These models are allowed only in the USA. This applies to
aftermarket manufactured home installations where the
home is sold, installed and permanently sited. Not for
manufactured home manufacturing factory installation These
units may not be installed in trailers or recreational vehicles.
WARNING: This product can expose you to chemicals
including epichlorohydrin which is known to the State of
California to cause cancer and birth defects and/or other
reproductive harm. For information go to
www.p65warnings.ca.gov

2
INSTALLATION RECORD
Model No.. Serial No.
Original Purchaser
Address
City and State Zip
Dealer
Address
City and State Zip
Installation Date Name Signature
(Dealer or authorized representative who certifies that this appliance is installed in accordance with Manufacturer’s instructions and local codes.)
WARRANTY
The manufacturer, Williams Furnace Co., warrants this wall furnace
or heater to the original purchaser under the following conditions:
LIMITED ONE-YEAR WARRANTY
1. Any part thereof which proves to be defective in material or
workmanship within one year from date of original purchase
for use will be replaced at the Manufacturer’s option, FOB to its
factory.
2. No liability is assumed by the Manufacturer for removal or
installation labor costs, nor for freight or delivery charges.
LIMITATIONS
1. THIS LIMITED WARRANTY IS THE ONLY WARRANTY MADE BY
THE MANUFACTURER, IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR
PURPOSE ARE LIMITED TO THE SAME ONE YEAR TERM AS
THE EXPRESS WARRANTY. UNDER NO CIRCUMSTANCES
SHALL THE MANUFACTURER BE LIABLE FOR INCIDENTAL,
CONSEQUENTIAL, SPECIAL OR CONTINGENT DAMAGES OR
EXPENSES ARISING DIRECTLY OR INDIRECTLY FROM ANY
DEFECT IN THE PRODUCT OR ANY COMPONENT OR
FROM THE USE THEREOF. THE REMEDIES SET FORTH HEREIN
ARE THE EXCLUSIVE REMEDIES AVAILABLE TO THE USER AND
ARE IN LIEU OF ALL OTHER REMEDIES.
Some states do not allow limitation on how long an implied
warranty lasts, and some states do not allow the exclusion or
limitation of incidental or consequential damages, so the above
limitations or exclusions may not apply to you.
2. This warranty does not include any charge for labor or
installation.
3. This warranty does not extend to painted surfaces or to damage
or defects resulting from accident, alteration, misuses or abuse
or improper installation.
4. This warranty does not cover claims which do not involve
defective workmanship or materials.
DUTIES OF THE CONSUMER
1. The heating equipment must be installed by a qualified installer
and operated in accordance with the installation and
homeowner’s instructions furnished with the equipment.
2. Any travel, diagnostic costs, service labor, and labor to repair
the defective unit will be the responsibility of the owner.
3. A bill of sale, cancelled check, payment record or permit should
be kept to verify purchase date to establish the warranty
period.
4. Have the installer enter the requested information in the
space below.
GENERAL
1. The manufacturer neither assumes nor authorizes any person
to assume for it any other obligation or liability in connection
with said equipment.
2. Service under this warranty should be obtained by contacting
your dealer. Provide the dealer with the model number, serial
number, and purchase date verification.
3. If, within a reasonable time after contacting your dealer,
satisfactory service has not been received, contact: Customer
Service Department, 250 West Laurel Street, Colton, CA 92324
for assistance.
4. THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS AND
YOU MAY ALSO HAVE OTHER RIGHTS WHICH VARY FROM
STATE TO STATE.

3
CONTENTS
Your Williams Warranty ............................................................................. 2
Installation Record ...................................................................................... 2
Table of Contents ........................................................................................ 3
Safety Rules ................................................................................................... 4
Introduction .................................................................................................. 5
Basic MaterialsNeeded .............................................................................. 5
Basic Tools Needed ..................................................................................... 5
Optional Accessories ................................................................................ 5
Installing Your Wall Furnace ................................................................. 6
Locating Wall Furnace and Thermostat ............................................ 6
Combustion & Ventilation Air .............................................................. 7-9
Installation
Recessed Mount Installation ............................................................ 10-11
Surface Mount Installation ................................................................. 12-13
Vent Installation ........................................................................................... 14
Attaching Your Furnace ................................................................... 15-16
Gas Supply and Piping ..................................................................... 16-18
FrontPanelInstallation...............................................................................18
ThermostatInstallation..............................................................................18
Start Up Procedure ................................................................................19
Stay Safe ......................................................................................................... 20
Operating Your Furnace ......................................................................... 21
How to Care for Your Furnace ................................................................ 21
Installing Your Motorized Rear Outlet Accessory ........................ 22
Motorized Rear Outlet Replacement Parts ................................. 25
Furnace Replacement Parts ................................................................ 26
Wiring Diagram ...................................................................................... 28
TroubleshootingChart............................................................................. 29
ServiceHints.................................................................................................. 30
Quick Reference
Here’s how to:
Installing Your Furnace ............................................................................10
Recessed Mount, Surface Mount, and Vent Installation are
explained starting on page 6.
Operating Your Furnace ..........................................................................21
Igniting your furnace for the first time.
Caring for Your Furnace ...........................................................................21
Learn how to keep your new Williams Furnace operating.

4
SAFETY RULES
WARNING: Read these rules and the instructions
carefully. Failure to follow these rules and instructions
could cause a malfunction of the furnace. This could
result in death, serious bodily injury and/or property
damage. INSTALLATION MUST CONFORM TO LOCAL
CODES. IN THE ABSENCE OF LOCAL CODES,
INSTALLATION MUST CONFORM TO THE NATIONAL FUEL
GAS CODE, ANSI Z223.1. THE APPLIANCE, WHEN INSTALLED
MUST BE ELECTRICALLY CONNECTED AND GROUNDED IN
ACCORDANCE WITH LOCAL CODES OR, IN THE ABSENCE
OF LOCAL CODES, WITH THE CURRENT NATIONAL
ELECTRICAL CODE ANSI/NFPA NO. 70.
IN CANADA: Installation must conform to local codes or,
in the absence of local codes, the current CAN/CGA B149
Installation code. The appliance, when installed, must
be grounded in accordance with local codes, with the
current CSA C22.1 Canadian Electrical Code. Reference
is made in this manual regarding gas type as L.P.G. Be
advised that L.P.G. is not available in Canada; refer to
Propane/L.P. Gas.
WARNING: Do not use this furnace if any part has
been under water. Immediately call a qualified service
technician to inspect the furnace and to replace any
part of the control system and any gas control which has
been under water.
1. Use only manufacturer’s replacement parts. Use of any
other parts could cause injury or death.
2. DO NOT install the furnace where it could be isolated by
closing doors to the heated space.
3. DO NOT install these furnaces in a travel trailer,
recreational vehicle or mobile home.
4. MAINTAIN all clearances specified in section “Locating
Wall Furnace and Thermostat” and “Vent Installation.”
5. BE SURE the furnace is for type of gas being used. Check
the nameplate by the gas valve in the lower cabinet.
Do not change it to use other gases without the proper
manufacturer’s gas conversion kit.
6. For natural gas, the minimum inlet gas supply pressure
for the purpose of input adjustment is 5” water column.
The maximum inlet gas supply pressure is 7” water
column.
7. Any safety screen, guard or parts removed for servicing this
appliance must be replaced prior to operating the
appliance to avoid property damage, bodily injury or death.
8. Vent the furnace directly to the outdoors, so that harmful
gases will not collect inside the building. Follow the
venting instructions for your type installation exactly. Use
only the type and size of vent pipe and fittings specified.
9. Provide for adequate combustion and ventilation air. See
page 7. The flow of this air to the furnace must not be blocked.
10. NEVER vent flue gases into another room, a fireplace
or any space inside a building. This could cause property
damage, bodily injury or death.
11. NEVER test for gas leaks with an open flame. Use a soap
solution to check all gas connections. This will avoid the
possibility of fire or explosions.
12. ALLOW furnace to cool before servicing. Always shut off
electricity and gas to furnace when working on it. This
will prevent any electrical shocks or burns.
13. DUE TO HIGH TEMPERATURES, locate the furnace out of
traffic and away from furniture and draperies.
14. ALERT children and adults to the hazards of high surface
temperatures and warn them to keep away to avoid
burns or clothing ignition.
15. CAREFULLY supervise young children when they are in
the same room with the furnace.
16. DO NOT place clothing or other flammable material on
or near furnace.
17. INSTALLATION and REPAIR must be done by a qualified
service person. The appliance should be inspected
before use and at least annually by a professional service
person. More frequent cleaning may be required due
to excessive lint from carpeting, bedding material, etc.
It is imperative that control compartments, burners and
circulating air passages be kept clean.
18. BEFORE INSTALLING: To avoid electrical shock, turn off
electrical circuits that pass through the wall where you
are going to install the furnace.
19. BE AWARE of good safety practices by wearing personal
protective equipment such as gloves and safety glasses
to avoid being injured by sharp metal edges in or around
the furnace while cutting or drilling holes in wood and/or
sheet metal.
20. CAUTION: Label all wires prior to disconnection when
servicing controls.
21. DO NOT store or use gasoline or other flammable liquids
or vapors near the furnace.
WARNING: Do not install any of these furnaces in mobile
homes, trailers or recreational vehicles.

5
INTRODUCTION
The following steps are all needed for proper installation
and safe operation of your furnace. If you have any doubts
as to any requirements, check with local authorities. Obtain
professional help where needed. All of the checks and
adjustments in the Start-Up Procedures are vital to the
proper and safe operation of the furnace. Please read the
instructions before you install and use your furnace. This
will help you obtain the full value from this furnace. It could
also help you avoid needless service costs if the answer to
the problem is found within this instruction manual.
Always consult your local heating or plumbing inspector,
building department or gas utility company regarding
regulations codes or ordinances which apply to the
installation of a vented wall furnace.
Check the furnace nameplate, located in the burner
compartment, to make sure your furnace is equipped to
operate on the type of gas available (either natural or L.P.
gas). DO NOT convert the furnace from natural gas to
L.P. gas or from L.P. gas to natural gas without the proper
manufacturer’s gas conversion kit.
Combustion air is drawn in from the room where the
furnace is located and is vented out of the top of the furnace
vertically through vent piping in the stud space to a roof
vent top. Vent material is not supplied with the furnace.
This furnace is equipped with a vent safety shutoff
system designed to protect against improper venting of
combustion products. Operation of this wall furnace when
not connected to a properly installed and maintained
venting system or tampering with the vent safety shutoff
system can result in carbon monoxide (CO) poisoning and
possible death.
The efficiency rating of this furnace is a product thermal
efficiency rating determined under continuous operating
conditions and was determined independent of any
installed system. The furnace will not function unless the
venting system is installed
Basic Materials Needed
Pipe and fittings to make gas connections to the furnace.
Vertical venting materials. See page 14, Figure 8.
Pipe Joint Compound resistant to L.P. Gases.
Electrical wiring supplies as needed. Minimum wire size is
#14 gauge copper.
Basic Tools Needed
Hand drill or properly grounded electric drill
Expansion bit 1/2” to 1-5/8” or 1/2” and 1-1/2” blade bits
1/8” and 3/16” drill bit (metal)
6 ft. folding rule or tape measure
Screwdriver (medium blade)
Screwdriver (Phillips and Flat Head)
Pliers (wire cutting)
Hammer
Stud Locater or small finishing nails
Tin Snips
8"adjustable wrench
12"adjustable wrench
7/8" wrench
3/4"wrench
1"wrench
Gloves and safety glasses
Helpful Installation Information
The following booklets will help you in making the installation:
ANSI/NFPA 70, or current edition “National Electrical Code”.
In Canada: CSA C22.1 Canadian Electrical Code.
American National Standard Z223.1 or current edition of the
“National Fuel Gas Code.”
Obtain from the American National Standard Institute, Inc.,
1430 Broadway, New York, NY 10018. In Canada, CAN/CGA B149.
Optional Accessories
Free Standing Accessory 4901 - This accessory allows the
furnace to be mounted on the surface of a wall.
Vent Adapter Kit 9902 - Optional vent adapter, typically used
when the furnace is vented into a properly lined chimney.
Rear Outlet Registers 6901, 6919, 6920 - When recessed
into a standard 2x4 inch interior stud partition, this accessory
directs some of the heated air into the room opposite the one
in which the furnace is installed.
Oval B/W Vent Kit 9929 - This U.L. listed B/W vent kit
contains four feet of oval, double-walled vent pipe, plate
spacers and base or hold-down plate that starts the venting
from the top of furnace. See Vent Installation on page 14 for
additional items you will need.

6
INSTALLING
YOUR FURNACE
The following steps are needed for proper installation and
safe operation of your furnace. If you have any doubts as to
any requirements, obtain professional help. Remember to
ALWAYS consult your local heating or plumbing inspector,
building department or gas utility company regarding
regulations, codes, or ordinances which apply to the
installation and location of a vented wall furnace.
IMPORTANT
For satisfactory and trouble-free operation, be sure to:
1. Locate the furnace properly within the space to be
heated.
2. Install the furnace in accordance with local codes or
ordinances and instructions provided. In the absence of
local codes or ordinances, install the furnace to conform
with the current edition of the National Fuel Gas Code,
NFPA 54, ANSI Z223.1/Canadian Installation Code, CAN/
CGA B149.
3. Maintain minimum clearances: Floor 2½-inches, ceiling
16- inches, side wall 1-inch.
4. Provide enough combustion and ventilation air.
Locating Wall Furnace & Thermostat
The furnace is installed between 2x4 inch wall studs spaced
on 16-inch centers or a stud space that can be framed in to
16-inches. Consider the following points before attempting
to install the furnace:
CAUTION: Do not make cutouts in the wall or ceiling
before checking in the attic for ceiling joist locations and
proposed venting.
FIGURE 1 – Minimum Spacing
1. Locate the furnace near the center of the space to be
heated for good air circulation. Do not put it behind a
door or draperies. Do not install the furnace where it
could be isolated by closing doors to the heated space.
Do not locate the furnace where a door could swing over
the front panel or where circulation could be retarded by
furniture or cabinets.
2. Check the minimum spacing needs as shown in Figure 1.
3. The top of the furnace must be at least 16-inches from
the ceiling.
4. When the furnace is properly installed with legs resting
on the floor plate, it sets the dimension from the face
panel to the bare floor. (Approximately 2½-inches
depending on the thickness of floor plate).
5. A protective barrier (metal or wood), cut to match the
width and depth of the furnace, should be used to cover
over any floor coverings such as carpet or vinyl under the
furnace. At no time should the dimension from the
bottom of the face panel to the protective barrier be less
than 1½- inches.
6. In the space to be heated, the side of the furnace may
be as close as 1-inch to an intersecting wall. The recessed
portion may have 0-inches clearance to combustible
material.
7. Select a location that will provide adequate accessibility
clearance for servicing and proper operation.
8. After picking a location, inspect the wall, floor, attic and
roof areas. Make sure there are no pipes, wiring, bracing,
etc., that will interfere with furnace or vent installation. If
required, move them or pick a new installation location.
9. Be sure that gas piping and electrical wiring can be
brought to the location. Electrical wiring is required for
optional blower accessory.
10. If installing the thermostat on the wall, locate the
thermostat approximately 5-feet above the floor on an
inside wall where it will sense the average room
temperature.
The thermostat should be sensing average room
temperature; avoid the following:
HOT SPOTS:
Concealed pipes or ducts
Fireplaces
Registers
TV sets
Radios
Lamps
Direct sunlight
Kitchen
COLD SPOTS:
Concealed pipes or ducts
Stairwell - drafts
Door - drafts
Unheated rooms on
other side of wall
DEAD SPOTS:
Behind doors
Corners and alcoves
7 MIN.
BARE
FLOOR
1 MIN. TO
CLOSET
SIDE WALL
WALL
FURNACE
WALL
APPROX. 2½
CEILING 16 MIN.

7
After picking a location that meets the requirements, check
the walls, attic and roof to make sure there are no obstructions
such as pipes, electrical wiring, etc., which could interfere with
the installation of the furnace or vent pipe. If required, move
them or pick a new location.
WARNING: Danger of property damage, bodily injury or
loss of life. Do not install the furnace in any area where
oxygen is in use.
Combustion & Ventilation Air
When an existing category I heater is removed or replaced,
the original venting system may no longer be sized to
properly vent the attached appliances.
WARNING:
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below for each appliance
connected to the venting system being placed into operation
could result in carbon monoxide poisoning or death.
The following steps shall be followed for each appliance
connected to the venting system being placed into operation,
while all other appliances connected to the venting system
are not in operation:
1. Seal any unused openings in the venting system.
2. Inspect the venting system for proper size and horizontal
pitch, as required in the National Fuel Gas Code, ANSI
Z223.1/NFPA 54 or the Natural Gas and Propane
Installation Code, CSA 8149.1 and these instructions.
Determine that there is no blockage or restriction,
leakage, corrosion and other deficiencies which could
cause an unsafe condition.
3. As far as practical, close all building doors and windows
and all doors between the space in which the
appliance(s) connected to the venting system are located
and other spaces of the building.
4. Close fireplace dampers.
5. Turn on clothes dryers and any appliance not connected
to the venting system. Turn on any exhaust fans, such as
range hoods and bathroom exhausts, so they are
operating at maximum speed. Do not operate a summer
exhaust fan.
6. Follow the lighting instructions. Place the appliance
being inspected into operation. Adjust the thermostat
so appliance is operating continuously.
7. Test for spillage from draft hood equipped appliances
at the draft hood relief opening after 5 minutes of main
burner operation. Use the flame of a match or candle.
8. If improper venting is observed during any of the above
tests, the venting system must be corrected in
accordance with the National Fuel Gas Code, ANSI Z223.1/
NFPA 54 and/or Natural Gas and Propane Installation
Code, CSA 8149.1
9. After it has been determined that each appliance
connected to the venting system properly vents when
tested as outlined above, return doors, windows, exhaust
fans, fireplace dampers and any other gashed burning
appliance to their previous conditions of use.
WARNING: Danger of property damage, bodily injury
or loss of life. The furnace and any other fuel-burning
appliances must be provided with enough fresh air for
proper combustion and ventilation of flue gases. Most
homes will require that outside air be supplied into the
heated area.
The high cost of energy for home heating has brought about
new materials and methods used to construct or remodel most
current homes. The improved construction and additional
insulation has reduced the heat loss and made these homes
much tighter around windows and doors so that infiltrated air
is minimal. This creates a problem to supply combustion and
ventilation air for gas-fired or other fuel burning appliances.
Any use of appliances that pull air out of the house (clothes
dryers, exhaust fans, fireplaces, etc.) increases this problem and
appliances could be starving for air.
The combination of a tight energy efficient home with the use
of exhaust fans, fireplaces, clothes dryers, and gas appliances
result in more and more air being drawn from the house until
fresh air may be sucked back into the house down a furnace
flue or fireplace chimney. Carbon monoxide can be the result.
Carbon monoxide (CO) is a colorless, odorless gas produced
when fuel is not burned completely or when the flame does
not receive sufficient oxygen. Automobiles, charcoal, wood fires
and improperly vented or air-starved coal, oil and gas furnaces
or other appliances can produce carbon monoxide.
Do not install furnace in the same room or near a wood solid
fuel burning fireplace.
Be aware of these air-starvation signals:
1. Headaches, nausea, dizziness.
2. Excessive humidity shown by heavily frosted windows or
a moist “clammy” sensation.
3. Fireplace smoke fills the room or will not draw.
4. Furnace flue backs up.
Air requirements
The requirements for providing air for combustion and
ventilation are listed in the National Fuel Gas Code NFPA
54/ANSI Z223.1 (in Canada: CAN/CGA B149). Most homes
will require that outside air be supplied to the heated area
by means of ventilation grilles or ducts connecting directly
to the outside or spaces open to the outdoors such as attic
or crawl space. The only exception is when the heated area
meets the requirements and definitions for an unconfined
space with adequate air infiltration.
All air openings and connecting ducts must comply with
the following:
If the furnace is installed in an area with another gas
appliance(s), the total input rating of all appliances must be
considered when determining the free area requirements
for combustion and ventilation air openings.

8
INSTALLING
YOUR FURNACE
Ducts must have the same cross-sectional area as the free
area of the openings to which they connect. The minimum
dimension of rectangular air ducts must not be less than
3-inches in length or height.
WARNING: Danger of property damage, bodily injury
or loss of life. Even when a house meets requirements
for unconfined space with adequate air infiltration, it
is recommended that a fresh air intake be installed to
lessen the possible dangers from any future changes
on the home.
Louvers / grilles and screens covering free area openings
If a screen is used to cover the opening(s), it must not be
smaller than 1/4-inch mesh. Use the free area of a louver or grille
to determine the size opening required to provide the free area
specified. If the free area is not known, assume a 20% free area
for wood and a 60% free area for metal louvers or grilles.
Infiltration Air
If your furnace is in an open area (unconfined space), the air
that leaks through the cracks around doors and windows
may be enough for combustion and ventilation air. The doors
should not fit tightly. The cracks around windows should not
be caulked or weather stripped.
Spillage means air starvation. A fresh air duct or air intake
opening must be installed to provide air directly to the
furnace or other gas appliances.
If spillage exists or when the furnace is in a building of tight
construction where the windows and doors are weather
stripped, air for combustion and ventilation must be
obtained from outdoors or space open to the outdoors.
To determine if infiltration air is adequate, perform the
following checks:
1. Close all doors and windows. If you have a fireplace, start
a fire and wait until flames are burning vigorously.
2. Turn on all exhausting devices, i.e., kitchen and bathroom
exhaust fans; water heaters (gas and electric).
3. Turn on all vented gas appliances, i.e., heating equipment
(includes any room heaters), water heaters.
4. Wait ten (10) minutes for drafts to settle.
5. Check for draft hood spillage at each appliance. Hold a lit
match two-inches from the draft opening. (Figure 2).
A. No Spillage
If the match flame pulls toward draft hood, this indicates
sufficient infiltration air. Return exhausting devices and
appliances to the condition you found them.
B. Draft Hood Spills
If there is spillage at a draft hood (match goes out or flame
wavers away from draft hood), check for plugged flue
connectors and chimneys. Repair blockage and test again.
FIGURE 2 – Draft Hood Spillage
If you have a fireplace, open a window or door near the
fireplace and then check for spillage. If spillage stops, do not
use the fireplace without a nearby window or door open until
you can supply fresh air by a permanent duct.
If you have kitchen and bathroom exhaust fans, turn them
off and check for spillage. If spillage stops, do not use exhaust
fans (circuit breakers for fans should be turned off) until you
can supply fresh air by a permanent duct.
Provide opening(s) having a total free area of one-square-
inch per 4,000 BTU/hr. of the total combined input ratings
for all appliances in the area. The required free area is shown
in Figure 3. This fresh air opening or duct must terminate at
a point not more than one-foot above the floor. It must have
at least one-square inch of free area for each 4,000 BTU/hr. of
input of all appliances in area.
FIGURE 3 – Free Area
Free Area in Square Inches.
Each opening is based on one square inch per 4,000 BTU/hr
BTU/hr input
30,000
35,000
40,000
45,000
50,000
60,000
Square inches
of opening
7.5
8.75
10.00
11.25
12.50
15.00
1 - 1/2
7
8
9
10
11
13
2
4
5
5
6
8
8
3
2
2
3
3
3
4
Required number of holes
sill or header plates
DRAFT HOOD
OPENING
(match or smoke pen)

9
Hole Placement - Example
Furnace located in unconfined space
An unconfined space must have a volume of a minimum 50
cubic feet per 1,000 BTU/hr. of the total combined input of
all appliances in the area. Adjoining rooms may be included
only if there are no doors between the rooms or if special
provisions are made such as ventilation grilles installed
between connecting rooms. Figure 4 outlines the minimum
area in square feet, based on 8-foot ceiling heights for various
BTU/hr. input ratings.
FIGURE 4 - Minimum Area
Examples of Grill Placement
Furnace located in confined space
If a furnace is installed in a confined space, it must be
provided with free air for proper combustion and ventilation
of flue gases by one of the following methods:
A. Air From Inside the Building
If the confined space adjoins an unconfined space, provide
two permanent openings. One within 12-inches of the top
and another within 12-inches of the bottom of the room
directly connected to the unconfined space. Each opening
must have a free area of at least 100-square inches or 1-square
inch per 1,000 BTU/hr. of input for all appliances combined.
WARNING: Danger of property damage, bodily injury
or death. The adjoining unconfined space must have
adequate air infiltration.
B. Air From Outdoors
If confined space does not adjoin an unconfined space, then
air must be provided from outdoors or spaces open to the
outdoors such as an attic or crawl spaces.
Openings for inlet or outlet air should NOT be made into an
attic area if the attic is equipped with a thermostat controlled
power vent.
Provide two permanent openings, one within 12-inches of
the top and bottom of the room connecting directly to, or by
using ducts, with the outdoors or areas open to fresh air.
If the opening connects directly to, or with vertical ducts, the free
area of each opening must be at least 1-square inch per 4,000
BTU/hr. of the combined input of all appliances in the area.
If horizontal ducts are used, the free area of each opening
must be at least 1-square inch per 2,000 BTU/hr. of the
combined input of all appliances in the area.
HOLES FROM VENTILATED
ATTIC INTO STUD SPACE
AIR GRILLS TO STUD SPACE
12 MAX FROM FLOOR
HOLES FROM VENTILATED
CRAWL SPACE INTO STUD SPACE
HOLES IN BOTTOM ON BACK OF FURNACE INTO OPEN
STUD SPACE OR CRAWL SPACE
4,000 BTU/hr. per
square inch opening
Round duct dia.
4
4
4
4
4
4 ½
Rectangular
square duct size
3 x 3
3 x 3
3 x 4
3 x 4
3 x 5
3 x 5
*Uncontained space
min. area in sq. ft.
8 ceiling height
145
219
240
281
312
375
Max.
BTU/hr input
30,000
35,000
40,000
45,000
50,000
60,000
*Can be two or more rooms separated by ventalition gas fire.
VENTILATION GRILLES CONNECTING TWO
ROOMS TO MEET UNCONFINED SPACE
100 SQ IN
200 SQ IN
MINIMUM
BETWEEN
LARGE
ROOMS
100 SQ IN
RECOMMENDED FRESH AIR DUCT INTO CRAWL
SPACE IN FURNACE AREA OR IN CLOSET WITH
WATER HEATER
VENTILATION
GRILLES
INTO CLOSET
FOR HOT
WATER
HEATER

10
INSTALLING
YOUR FURNACE
WARNING: Danger of illness, bodily injury or death. Draft
hood spillage, with unobstructed vents, indicates that
additional air must be brought into the structure from
the outside. Keep a window open (minimum 2-inches
near the appliance until a permanent air duct is installed.
FIGURE 5- Recessed Wall Mount Installation
Examples of Air Inlets and Outlets
Recessed Wall Mount
Installation
The maximum recess depth from rear of furnace forward
is 4½-inches.
Find the studs and ceiling joints
Use a stud locater or small finishing nails. Repeatedly drive and
remove a nail into the wall in the area of the stud until it
is located. Then find the inside edge of the stud. Leave the
nail at this location.
The other stud should be about 14½-inches from the one
found. Drive finishing nails on the inside of this stud. Draw wall
cutout to required size as shown in Figure 5. If wall studs are not
on 16-inch centers. See “CLOSE OFF STUD SPACE.” (Figure 6).
Cut wall opening
Cut wall opening 14⅜-inches wide and 66⅛-inches high
measured from the top of the floor plate. (Figure 5). All corners
must be square.
Installation of rear outlet register
The optional rear outlet register may be installed when the
furnace is recessed into the wall. In new construction, install
the rear outlet plaster ground at the same time you install the
header plate. For existing construction, make the necessary
CHIMNEY OR GAS VENT
VENTILATED
ATTIC
OUTLET AIR
OUTLET AIR
INLET AIR
INLET AIR VENTILATED
CRAWL SPACE
10 CRAWL
SPACE
WALL
FURN
TO
ATTIC
12
OPTIONAL INLET AIR 1 SO
INCH PER 4,000 BTUH
100 SQ
INCHES
EACH
1 SQ INCH
PER 4,000 BTUH
MAX
12
2 x 4 STUDS
TOP OF
HEATER
FINISHED
FLOOR
2 X 4
FLOOR
PLATE
14 3/8
66 1/8
GAS STUB
LOCATION
B-W VENT
BASE PLATE
PLASTER TO TOP OF HEADER PLASTER GROUND
REAR REGISTER OPTIONAL FOR SINGLE
BURNER MODELS ONLY
PLASTER GROUND
NAIL FLANGE
8 18X 13 14
CUTOUT
REAR
OUTLET
REGISTER
OPENING
115.V OUTLET
FOR OPTIONAL
BLOWER
TOP OF HEADER
2 x 4
PLATE
ALTERNATE
GAS STUB
LOCATION
14 3/8
A = 4
MODELS
20,500 &
35,000
BTUHR.
A = 2 58
MODELS
50,000
BTUHR.
BOTTOM OF HEADER NAILING FLANGE
9 18
62 14
3 3/4
cutout and install the plaster ground before you install the
furnace. See instructions packed with accessory and Figure 5.
Do not allow wall finish material to project into the
furnace recess.
Do not install rear outlet register where grille may be blocked
by a door, curtains or any other obstruction.
Gas supply opening
A hole must be drilled for the gas line. Decide whether the
gas line will come through the floor or wall. Drill a 1½-inch
hole through the floor or wall as needed. (Figure 5).
CAUTION: Be careful not to damage any furnace
components while making any alternate hole.