COZY C255H Operating instructions

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.
25,000 - 35,000
BTU/hr.
TOP VENT GRAVITY GAS WALL HEATER
WARNING: Do not install any of these furnaces (natural
or propane gas) in mobile/manufactured homes, trucks 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
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 or, service agency.
SINGLE SIDED MODEL NUMBERS
(natural gas)
C255H / C355H
(propane gas)
C256H / C356H
DOUBLE SIDED MODEL NUMBERS:
(natural gas)
C505H
(propane gas)
C506H
SAVE THIS MANUAL FOR FUTURE REFERENCE.
READ THIS OWNER’S MANUAL CAREFULLY BEFORE YOU
INSTALL YOUR NEW Cozy WALL FURNACE.
50,000 BTU/hr.
OWNER'S MANUAL AND INSTALLATION INSTRUCTIONS
Cozy Heating Systems | cozyheaters.com | 888-444-1212 | 250 West Laurel Street | Colton, CA 92324

2COZY TOP VENT GRAVITY GAS WALL HEATER
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 Comfort Products, warrants this
Cozy wall furnace or heater to the original purchaser under the
following conditions: ANY WARRANTY CONSIDERATIONS
ARE CONTINGENT ON INSTALLATION BY A QUALIFIED
INSTALLER (CONTRACTOR). SELF-INSTALLATION IS
PROHIBITED AND WILL INVALIDATE YOUR WARRANTY.
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.
LIMITED EXTENDED WARRANTY
1. In addition to the above limited one year warranty on the
complete unit, any combustion chamber which burns out or
rusts under normal installation, use and service conditions
during a period of nine years following expiration of the
one-year warranty period will be exchanged for a like or
functionally similar part.
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, canceled 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.

COZY TOP VENT GRAVITY GAS WALL HEATER 3
WARRANTY
INSTALLATION RECORD
CONTENTS
SAFETY RULES
INTRODUCTION
BASIC MATERIALS NEEDED
BASIC TOOLS NEEDED
OPTIONAL ACCESSORIES
HELPFUL INSTALLATION INFORMATION
OPTIONAL ACCESSORIES
COMBUSTION & VENTILATION AIR
INSTALLING YOUR WALL FURNACE
RECESSED WALL MOUNT INSTALLATION
SURFACE MOUNT INSTALLATION
VENT INSTALLATION
ATTACHING YOUR FURNACE
GAS SUPPLY AND PIPING
FRONT PANEL INSTALLATION
THERMOSTAT INSTALLATION
START-UP PROCEDURE
OPERATING YOUR FURNACE
FOR YOUR SAFETY, READ BEFORE LIGHTING THE PILOT
OPERATING INSTRUCTIONS
LIGHTING THE PILOT
INSTALLING YOUR BLOWER ACCESSORY
HOW TO CARE FOR YOUR FURNACE
INSTALLING YOUR MOTORIZED REAR OUTLET ACCESSORY
PART NUMBERS FOR THE C255H / C256H / C355H / C356H MODELS
CONTROL ASSEMBLY REPLACEMENT PARTS
C255H / C256H / C355H / C356H MODELS
PART NUMBERS FOR THE C505H / C506H MODELS
CONTROL ASSEMBLY REPLACEMENT PARTS C505H / C506H MODELS
BLOWER ACCESSORY MODEL 2901 PARTS
BLOWER ACCESSORY MODEL 2907 PARTS
MOTORIZED REAR OUTLET REPLACEMENT PARTS
TROUBLESHOOTING YOUR FURNACE
HINTS AND INFORMATION
INSTALLATIONS IN THE STATE OF MASSACHUSETTS
QUICK REFERENCE - HOW TO:
INSTALLING YOUR FURNACE
OPERATING YOUR FURNACE
HOW TO CARE FOR YOUR FURNACE
2
2
3
4
5
6
6
6
6
6
8
11
11
12
15
15
17
19
19
20
21
22
22
23
25
26
27
29
31
32
34
35
36
37
38
40
40
11
21
26
CONTENTS

4COZY TOP VENT GRAVITY GAS WALL HEATER
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 propane Be advised that propane is not
available in Canada; refer to propane.
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.
SAFETY RULES

COZY TOP VENT GRAVITY GAS WALL HEATER 5
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 propane gas). DO NOT convert the
furnace from natural gas to propane gas or from propane 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.
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 B149.1 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.
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:
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 B149.1.
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
gas-fired burning appliance to their previous
conditions of use.
INTRODUCTION

6COZY TOP VENT GRAVITY GAS WALL HEATER
BASIC MATERIALS NEEDED
Pipe and fittings to make gas connections to the furnace.
Vertical venting materials. See page 15, Figure 8.
Pipe joint compound resistant to propane.
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
Blower Accessories 2901, 2907 - May be used on all models and
mounts on top of a furnace. This blower increases circulation of warm
air through the heated space. A 115V outlet adjacent to the furnace
is required.
Trim Strip Kit 4701 - Provides a finished edge for sides of the
wall furnace.
Free Standing Accessory 4901 - May be used with single&sided
models. This accessory allows the furnace to be mounted on the
surface of a wall.
Vent Adapter Kit 9902, 9910 - Optional vent adapter, typically used
when the furnace is vented into a properly lined chimney.
Rear Outlet Registers 6901, 6919, 6920 - May be used with
single&sided models 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&3own plate that starts the venting from the top of furnace. See
Vent Installation on page 15 for additional items you will need.
Plaster Ground Kit 6905 - Used for 6901 or 6919 Rear
Outlet Registers.
Gas Conversion Kits - See page 17.
Thermostat - See page 20.
INTRODUCTION

COZY TOP VENT GRAVITY GAS WALL HEATER 7
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 2 1/2-inches, ceiling
16- inches, side wall 1-inch.
4. Provide enough combustion and ventilation air.
LOCATING WALL FURNACE & THERMOSTAT (NOT INCLUDED)
The furnace is installed between 2 x 4 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 2 1/2-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 1 1/2- 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 (not included) 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 (not included) 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
CLOSEST
SIDE WALL
WALL
FURNACE
WALL
APPROX. 2 1/2"
CEILING 16" MIN.
INSTALLING YOUR FURNACE

8COZY TOP VENT GRAVITY GAS WALL HEATER
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.
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.
INSTALLING YOUR FURNACE

COZY TOP VENT GRAVITY GAS WALL HEATER 9
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)
VENT PIPE
TYPICAL WATER
HEATER
VENT PIPE
WALL
FURNACE
DRAFT HOOD
OPENING
(match or
smoke pen)
HOLE PLACEMENT - EXAMPLE
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
INSTALLING YOUR FURNACE

10 COZY TOP VENT GRAVITY GAS WALL HEATER
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.
4,000 BTU/hr. per
square inch opening
Round duct dia.
4"
4"
4"
4"
4"
4 1/2"
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 ventilation 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
EXAMPLES OF AIR INLETS AND OUTLETS
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.
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 BTU/hr.
100 SQ
INCHES
EACH
1 SQ INCH
PER 4,000 BTU/hr.
MAX
12
INSTALLING YOUR FURNACE
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.
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.

COZY TOP VENT GRAVITY GAS WALL HEATER 11
FIGURE 5 - RECESSED WALL MOUNT INSTALLATION
2" x 4" STUDS
TOP OF
HEATER
FINISHED
FLOOR
2 X 4
FLOOR
PLATE
14 3/8"
66 1/8"
GAS STUB
LOCATION
RECESSED WALL MOUNT INSTALLATION
Recessed wall mount installation on models:
C255H / C256H / C355H / C356H / C505H / C506H
The maximum recess depth from rear of furnace forward
is 4 1/2-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 14 1/2-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 14"-inches wide and 66"-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 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 1 1/2-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.
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"
INSTALLING YOUR FURNACE

12 COZY TOP VENT GRAVITY GAS WALL HEATER
CLOSE OFF STUD SPACE (IF REQUIRED)
If studs are not on 16-inch centers, cut the hole for the
furnace next to an existing stud and frame in the other
side using a 2 x 4 and spacer blocks as required. Figure 6
CEILING PLATE OPENING
Cut away the ceiling plate between the studs where the furnace is to
be installed. Work from the top in the attic. If there is no access to the
top, remove the wall covering between the two wall studs all the way
to the ceiling. Work through this opening. Cut out the entire plate
so the plate edges will be even with the inner face of the
2 x 4 studs. Figure 7
INSTALL VENT BASE PLATE (HOLD-DOWN PLATE)
Position base plate on top of header plate and fasten with screws.
Note: Hold down plate is not included.
HEADER PLATE (VENT SUPPORT)
Measure upward 62¼-inches from the top of the floor plate. Place a
mark on each stud at this distance. Figure 5. Place the header plate
between the studs with the lower edges even with marks on the
studs. Make sure header plate is level.
Locate rear edge of nailing tabs at back of the header. Nail header
plate to the 2 x 4 studs which will center the vent collar in the wall.
Figure 5
INSTALL CEILING PLATE SPACER
Nail the ceiling plate spacers either across or in between the cut out
section of ceiling plate. If nailed between, ends must be bent at 90
degrees. They must be fastened along each long edge of the ceiling
plate hole to hold the oval vent pipe in the center of the hole. Ceiling
plate spacers preserve structural strength and position oval vent pipe
in the center of the cut out opening. Ceiling plate spacers are not
included. Figure 7
FIGURE 6 – CLOSE OFF STUD SPACE
FIGURE 7 – CEILING PLATE OPENING
CEILING PLATE
EXISTING STUD
FLOOR PLATE
EXISTING STUD
NEW STUD
SPACER
BLOCKS
AS REQ'D
14 3/8"
CEILING PLATE
SPACERS NAILED
IN BETWEEN
CEILING PLATES
OR ACROSS FACE
IF ACCESSIBLE
PLATE SPACER
CEILING PLATE 14 3/8"
2 X 4 STUD
2 X 4 STUD
SURFACE MOUNT INSTALLATION
The use of the optional Free Standing Accessory No. 4901 allows
single-sided furnaces to be surface mounted instead of recessed
into a wall. This is ideal for remodeling existing masonry wall
construction or when studding is substandard. This kit drastically
cuts installation time and eliminates the expense of cutting into the
walls and ceiling plates. Be sure this accessory is of the type and
design required for the use with your furnace.
NOTE: After picking a location that meets the requirements, check
the wall, 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.
FIND THE WALL STUDS OR CEILING JOISTS
Find two studs or joists at the spot where the furnace is to be
located. Use a stud locater or small finishing nails. Repeatedly
drive and remove a nail into the wall or ceiling in the area of the
stud or joust until you find it. Then find the its side and leave the
nail there. Drive another nail just on the other side other the same
stud or joist.
The inside of the next stud or joist should be about 14 1/2 inches
from the first one found. Drive a nail on the inside of this stud or joist.
Using the nails as a guide, draw two lines down the side of
the wall from the ceiling to locate the furnace and ceiling
hole cutout for venting.
FREE STANDING ACCESSORY ASSEMBLY & INSTALLATION
1. Attach the base plate panel as shown in Figure A to the
bottom of the side rails with four (4) # 6, 3/8" screws.
2. Attach the header plate, (included with the furnace), to
the side rails using four (4) #8, 3/8’ screws. Flanges of the
header plate go against the wall. Figure A
3. Install extension side rails as shown in Figure A, by
telescoping them inside the lower side rails. Adjust the
extension side rails by sliding them up or down to
ceiling height. Maximum: 8 feet 9 inches, Minimum:
7 feet 9 inches.
INSTALLING YOUR FURNACE

COZY TOP VENT GRAVITY GAS WALL HEATER 13
4. If the wall has a baseboard, cut the baseboard out to fit
against the side rails. Stand the side rails against the wall and
fasten them to the wall securely with screws or bolts in the
holes provided. Use a level to assure the enclosure is plumb.
Screws and bolts for wall fastening are not included.
5. After positioning the enclosure, cut a 3 1/2 X 14 inch hole in
the ceiling, centered between the studs or joists as shown
in Figure B.
6. Cut ¼ inch off each end of the ceiling spacer plate. Place the
ceiling spacer plate to the back of the wall and centered in the
enclosure as shown in Figure C.
7. Install Type B/W vent though the roof and studs or joists
in accordance with the installation instructions packed with the
furnace and local codes. See Vent Installation, page 15.
8. Set the furnace body into position. Figure 9 page 16. The
furnace legs will rest on the bottom of the base plate panel.
Utilizing the holes provided in the furnace legs, secure the
furnace to the brackets attached to the bottom panel with
two (2) #10, 3/4" screws.
9. Install the vent enclosure panel, fastening it to the side rails
with six (6) #6, 3/8" screws. Trim the bottom of the panel to
fit the header plate.
10. Install gas inlet through the back wall or one of the two
holes provided in the bottom base plate panel. Figure D
Connect gas line to furnace. See Gas supply and Piping,
page 17.
11. Install furnace face panel. See Front Panel Installation,
page 19. NOTE: The panel recesses ¼-inch between the
vertical edges of the enclosure.
FIGURE A
HEADER PLATE
SIDE RAIL
SIDE RAIL
BASE PLATE PANEL
INSTALLING YOUR FURNACE
FIGURE B
STUD WALL
CENTERED
14"
3 - 1/2"
FIGURE C
STUD WALL
STUD WALL
16"
4 - 7/16"
A
PLUMBERS
TAPE
B-W VENT PIPING
CEILING PLATE SPACER
FIGURE D
STUD WALL
GAS STUB LOCATIONS

14 COZY TOP VENT GRAVITY GAS WALL HEATER
VENT INSTALLED
FRONT PANEL INSTALLED
VENT
HOLD DOWN
PLATE
HEADER
FURNACE
SIDE RAIL
BASE PLATE
PANEL
FIGURE 8 – TYPICAL VENT INSTALLATION
VENT CAP MUST BE MINIMUM 2 FEET
HIGHER THAN ANY POINT WITHIN
10 FEET OF THE VENT CAP
10 FEET
LISTED
VENT CAP
STORM
COLLAR
ROOF
FLASHING
HEIGHT FROM HEADER PLATE
TO THE VENT CAP TOP MUST
BE 6 FEET MINIMUM
1 INCH MIN. CLEARANCE TO COMBUSTIBLES
LISTED 4"ROUND B VENT
OVAL TO ROUND
ADAPTER
OVAL B/W VENT
(DOUBLE WALL)
PLATE SPACER
(RECESSED MOUNT)
2 REQUIRED
BASE PLATE (HOLD DOWN) OR
STARTER PLATE SCREWED
DOWN TO HEADER PLATE
NOTE: THESE PARTS ARE SUPPLIED WITH THE FURNACE
GASKET
HEADER PLATE AND GASKETS
PROVIDED WITH FURNACE
50,000 BTU/hr. MODEL SERIES AND HEADER NOT SHOWN
FLUE COLLAR GASKET NOT REQUIRED ON 500 MODEL SERIES
TAKE CARE NOT TO DISTURB
GASKET GLUED TO THE HEADER
UNDERSIDE. GASKET MAT4RIAL
MUST NOT BLOCK THE FLUE
EXTENSION.
FLUE COLLAR
GASKET
INSTALLING YOUR FURNACE

COZY TOP VENT GRAVITY GAS WALL HEATER 15
VENT INSTALLATION
The vent installation must comply with all local codes and ordinances.
If in doubt, consult your local codes or inspector.
The furnace vent must be directed to the outdoors so that harmful
combustion gases will not collect inside the building.
This furnace must not be connected to a chimney flue
serving a separate solid-fuel burning appliance.
This product is design certified to ANSI Z21.86. It must be installed
with a U.L. tested and listed type ’B’ approved vent and type
’B/W’ approved vent Figure 8 Older style terracotta, transite
pipe, clay, concrete or masonry type vent pipe cannot be used
with this appliance. These types of vent pipe will not heat fast
enough to establish a draft, which will result in improper venting
of combustion products. Consequently, this could cause the vent
safety control system to shut down the furnace.
FIGURE 8 – ALTERNATIVE VENTING
IF VENT EXTENDS OVER 5 FEET
ABOVE ROOF, GUY OR BRACE.
SEAL AROUND COLLAR
AND FLASHING
MAINTAIN LISTED
CLEARANCE
LOCK JOINTS
SUPPORT LATERALS
MAXIMUM VERTICAL RISE
MAINTAIN
LISTED
CLEARANCE
SUPPORT IF
NECESSARY
TYPE B ROUND OR OVAL
INSULATION SHIELD,
IF ATTIC IS INSULATED
ATTACH
HEADER
PLATE
MINIMUM
HEIGHT
12 FEET
FIRE STOP
SPACE
MULTISTORY
UPPER FLOORS
SHEET
METAL
SLEEVE
CEILING
SPACER
SINGLE STORY
OR FIRST FLOOR
OF MULTISTORY
SEAL AND
BASE PLATE
HEATER HEADER
PLATE
INSTALLING YOUR FURNACE
The area above header within the stud space MUST be kept clear
of any attic insulation to allow the free circulation of air around the
oval vent piping. In some areas the building code requires the use
of an attic shield.
The B/W vent must extend through the ceiling and roof terminating
at least 12-feet above the finished floor on
which the furnace rests.
INSTALL FURNACE VENT
Attach a 4-foot length of oval, double-wall vent pipe through the
plate spacers to the hold-down plate. Push the vent pipe into the
hold-down plate until it is completely seated. The hold-down cleat
will engage the groove in the vent pipe.
COMPLETE THE VENTING
Type B/W gas vent shall extend from the header plate of the
furnace to a point above the highest ceiling plate within the stud
space through which the vent passes, without any offsets or
crossovers. The first vent pipe offset, (if required), may not be any
closer than 2-feet from the header and needs to extend past the
ceiling plate. After a type B/W gas vent passes through the highest
ceiling plate within a stud space above the furnace to which it
serves, the vent system may be completed with a Type B gas vent,
from the SAME manufacturer (do not mix brands of pipe). Offsets
cannot be greater than 45 degrees from vertical. Refer to The
Uniform Mechanical Code.
Install the oval-to-round adapter. Complete the piping extending it
through the roof. Use a 4-inch round, double-
wall (Type B) vent pipe, roof flashing, storm collar and vent
cap as shown. The vent cap must be at least 2-feet higher
than any point that is within 10- feet of the vent cap. There
must be at least a 1-inch clearance between the vent pipe
and any combustible material.
CAUTION: To avoid damage to wiring, be sure to route the
wires away from the path of the furnace vent.
ATTACHING YOUR FURNACE
Clear the wall recess of all debris, remove any wood or plaster.
Stand the furnace in front of recess, holding the furnace body at
an angle. Insert flue collar into the opening in the header plate and
raise furnace carefully Figure 9. Swing bottom of furnace into wall
recess with front edges of legs flush with 2x4 floor plate. In the holes
provided, nail through the legs into studs or floor plate. Figure 10
Do not damage gasket glued to underside of header plate when
placing furnace in wall. Avoid nailing the legs so tightly that it disturbs
the inner furnace casing. Do not try to force the furnace into a
smaller-than-specified recess.
If an existing gas line is preventing the installation of a Cozy furnace,
a cut-out may be made using tin snips on one of the legs to clear this
existing gas line. This cut-out will be on one side of the unit on the
rear side of the leg and only if necessary.

16 COZY TOP VENT GRAVITY GAS WALL HEATER
FIGURE 9 – INSERT FURNACE
FIGURE 10 – NAIL PLACEMENT
FIGURE 11 – REMOVE KNOCKOUT PLATES
REAR OUTLET KIT INSTALLATION (OPTIONAL)
If a Rear Outlet Register Accessory is used, the following procedure
must be completed before placing furnace body into wall recess.
Figure 11 Attach speed nuts to outer shield and remove knockout
plates from both the outer and inner shields as follows:
1. Punch in the lower corners with a screwdriver blade.
2. Break the knockout side and bottom connecting tabs
by holding a screwdriver blade sideways against the
tab and striking the head of the screwdriver lightly with
a hammer.
3. Swing the plate outward; bend it back and forth to
break the top tabs. Use caution when handling sharp
metal edges.
CAUTION: Do not install rear outlet kit where grille may be
blocked by a door, curtains, or any other obstruction.
25,000 - 35,000 BTU/hr. MODELS
B/W VENT
INNER SHIELD
KNOCKOUT PLATE
ON OUTER SHIELD
HOLD SCREWDRIVER
SIDEWAYS AGAINST
TABS AND STRIKE
LIGHTLY WITH
HAMMER
10 - 24 SPEED NUT
BOTTOM OF
FURNACE
NAIL FURNACE LEG TO STUD
OR FLOOR PLATE
(SEE DETAIL BELOW)
FLOOR PLATE
LEG
NAIL AT ANGLE
BOTTOM OF FURNACE
After furnace is in position, install rear outlet register as shown
in Figure 12. Have damper in open position when inserting the
assembly. Secure the rear outlet register to speed nuts with the
machine screws furnished.
FIGURE 12 – MOUNTING REAR OUTLET REGISTER
FURNACE SHIELDS
REAR REGISTER
OUTLET
PLASTER GROUND
INSTALLING YOUR FURNACE
WARNING: Never shear or cut the furnace legs.

COZY TOP VENT GRAVITY GAS WALL HEATER 17
GAS SUPPLY AND PIPING
The gas control valve, in the furnace, is shipped with a seal over
the gas inlet tapping. Do not remove the seal until ready to connect
the piping.
WARNING: Danger of property damage, bodily injury
or death. Make sure the furnace is equipped to operate
o the type of gas available. Models designed as natural
gas are to be used with natural gas only. Models
designed for use with liquefied petroleum propane gas
have orifices sized for commercially pure propane gas.
They cannot be used with butane or a mixture of butane
and propane.
GAS SUPPLY
For propane gas the minimum inlet gas supply pressure for the
purpose of input adjustment is 11-inches water column. The
maximum inlet gas supply pressure is 13-inches water column.
For natural gas, the minimum inlet gas supply pressure for the
purpose of input adjustment is 5-inches water column. The
maximum inlet as supply pressure is 7-inches water column.
Gas pressure and input to the burners must not exceed the
rated input and pressure shown on the nameplate. The natural
gas manifold pressure should be 4-inches water column. The
manifold pressure should be 10-inches water column for propane
gas. For operation in elevations above 2,000 feet, a burner orifice
change may be required to suit the gas supplied. Check with your
local gas supplier.
ORIFICE SIZES
The efficiency rating of this appliance is a product thermal
efficiency rating determined under continuous operating
conditions and was determined independently of any installed
system. For elevations above 2,000 feet, reduce ratings 4% for
each 1,000 feet above sea level.
INSTALLING YOUR FURNACE
FURNACE TECHNICAL INFORMATION
MODEL
NUMBER
GAS
TYPE
INPUT
RATING
BTU/hr.
HEATING
CAPACITY
RATING
BTU/hr.
MAIN BURNER ORIFICE
DRILL DECIMAL
QUANTITY
C255H NATURAL 25,000 17,870 #43 0.089 1
C256H PROPANE 25,000 17,870 .057" 1
C355H NATURAL 35,000 23,700 #36 0.106 1
C356H PROPANE 35,000 23,700 .069" 1
C505H NATURAL 50,000 36,900 .091" 2
C506H PROPANE 50,000 36,900 .058" 2
GAS CONVERSION KITS
NATURAL GAS TO PROPANE GAS
8913 255H / 256H SERIES
8914 355H / 356H SERIES
8909 505H / 506H SERIES
PROPANE GAS TO NATURAL GAS
8915 255H / 256H SERIES
8916 355H / 356H SERIES
8912 505H / 506H SERIES
GAS PIPING
The gas supply line must be of adequate size to handle the Btu/hr.
requirements and length of the run for the unit being installed.
Determine the minimum pipe size from Figure 13, based on the
length of the run from the gas meter to the unit.
All piping must comply with local codes and ordinances or with the
National Fuel Gas Code (ANSI Z223.1 NFPA No. 54), whichever
applies. (In Canada: CAN/C.GA B149). Refer to FIGURE 14 for the
general layout of the unit. It shows the basic fittings needed.
The following rules apply:
1. Use new, properly reamed steel or black iron pipe and
fittings free of metal chips and debris that are approved by
local codes. Metal chips and debris can damage the valve.
2. Do not thread pipe too far. Valve distortion or malfunction
may result from excess pipe within the gas control valve.
Apply a moderate amount of good quality dope to the
pipe only. Leave the two end threads bare. Figure 15
3. Use ground joint unions.
4. Install a drip leg (sediment trap) to trap dirt and moisture
before it can enter the gas valve. The nipple must be a
minimum of 3-inches long.
5. Install a manual shutoff valve.
6. Provide a 1/8’ NPT test gauge connection immediately
before the gas supply connection to the furnace.
FIGURE 13 - PIPE CAPACITY - BTU/hr. WITH FITTINGS
NATURAL GAS
LENGTH OF
PIPE FEET
PIPE SIZE
1/2"
3/4" 1"
20
40
60
92,000
63,000
50,000
190,000
130,000
105,000
350,000
245,000
195,000
PROPANE
LENGTH OF
PIPE FEET
PIPE SIZE
1/2"
3/4" 1"
20
40
60
189,000
129,000
103,000
393,000
267,000
217,000
732,000
504,000
409,000

18 COZY TOP VENT GRAVITY GAS WALL HEATER
FIGURE 14 – GAS PIPING
FIGURE 15 – PROPER PIPING PRACTICE
PROPER PIPE
THREADING
INCORRECT
THREADING
2 THREADS EXPOSED
SEALANT THIN
ENOUGH TO SHOW
THREADS
OVER-THREADED
SEALANT
TOO THICK
SEALANT
PAST TIP
DAMAGED
THREADS
INSTALLING YOUR FURNACE
GAS CONNECTION
If the installation is for propane gas, have the propane installer use
a two stage regulator and make all the connections from the storage
tank.
Use two pipe wrenches when making the connection to the valve to
prevent turning and/or damage to the valve.
Connections between the manual shutoff valve and burner control
assembly can be made with an A.G.A./C.G.A. design certified flexible
connector if allowed by local codes. Drip leg and ground joint unions
are still required.
Tighten all joints securely.
Test all piping for leaks. When checking gas piping to the furnace
with gas pressure less than 1/2 PSI, shut off manual gas valve to the
furnace. If gas piping is to be checked with the pressure at or above
1/2 PSI, the furnace and manual shutoff valve must be disconnected
during testing. (SEE WARNING). Apply soap solution (or a liquid
detergent) to each joint. Bubbles forming indicate a leak. Correct
even the slightest leak at once.
WARNING: Danger of property damage, bodily injury
or death. Never use a match or open flame to test for
leaks. Never exceed specified pressures for testing.
Higher pressures may damage the gas valve and
cause over-firing which may result in component(s)
failure. Never attempt start-up of unit before thoroughly
ventilating the area and smelling near the floor for
gas odor.
MANUAL SHUT-OFF VALVE
1/8"NPT
PLUGGED
HOLE FOR
TEST
GAUGE
PIPED GAS SUPPLY
CAUTION: Shut off the main gas supply before removing the end cap to prevent gas from
filling the work area. Test for gas leakage when installation is complete.
CAUTION: All bends in metal tubing must be smooth.
HORIZONTAL
MANUAL SHUT-OFF VALVE
TEE
FITTING
HORIZONTAL
DROP
GROUND JOINT UNION
GAS
VALVE
GAS
VALVE
GAS
VALVE
PIPED GAS SUPPLY
TUBING GAS SUPPLY
2
1
2CAP
2CAP
2CAP
1
3" (76.2 MM) MINIMUM
3" (76.2 MM)
MINIMUM
3" (76.2 MM) MINIMUM
MANUAL
SHUT-OFF VALVE
NIPPLE
NIPPLE
TEE
FITTING
NIPPLE
RISER
RISER
DROP
GROUND JOINT
UNION
GROUND JOINT UNION

COZY TOP VENT GRAVITY GAS WALL HEATER 19
FRONT PANEL INSTALLATION
Place the front panel top over the channel on the header plate, as
shown in Figure 16. Press the panel tight against wall, and secure
it to the header channel with the screw provided in final assembly
package. Open the control door at bottom of panel and fasten the
panel at each side through slots in flanges with screws provided.
Attach handle to the front panel door with the screw provided.
Install the second face panel in same manner for 500
Series models.
FIGURE 16 – PANEL PLACEMENT
INSTALLING YOUR FURNACE
THERMOSTAT INSTALLATION (Sold Separately)
Use Cozy thermostat P322016 or any millivolt thermostat. Current
to the thermostat is supplied by the pilot generator. Do not connect
it to electricity. Anticipator settings are not required.
1. Use of existing wire is acceptable if it is in a satisfactory location
and the wire is in good condition. When in doubt,use new wiring.
2. If a new location is chosen or if this is a new installation,
thermostat wire must first be run to the location selected. All wiring
must agree with local codes and ordinances. These instructions
cover bringing the wire down from the attic but it may be run from
a basement or crawl space using similar methods.
3. Before drilling a hole in the wall at the selected location,
drive a small finish nail through the ceiling in the corner of
the wall and ceiling above the thermostat location. Pull
the nail out and push a small, stiff wire through the hole
so it can be found in the attic. Drill a 1/2-inch hole through
the ceiling wall plate.
4. Probe for obstructions in the partition. Then, drill a 1/2-inch hole
through the wall at the selected location for the thermostat.
5. From the attic, feed the thermostat wire through the wall until
even with the thermostat location.
6. Snag the thermostat wire through the hole and pull the wire
through the hole in the wall so that 6-inches of the wire protrude.
7. Route wires to the furnace.
8. Never use nails or staples across the thermostat wires.
CAUTION: Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and dangerous
operation. Verify proper operation after servicing. Refer to
installation instructions packed in the thermostat carton if you
have any doubt about the above procedures.
WALL-MOUNTED THERMOSTAT INSTALLATION
1. To remove the thermostat cover, squeeze both sides and lift.
2. Connect the thermostat wires to the terminal screws on
the base of thermostat.
3. Push any excess wire back through hole in the wall and plug
hole with insulation to prevent drafts from affecting
thermostat operation.
4. Be sure to level the thermostat for best appearance. Fasten
thermostat base to the wall through mounting holes with
screws provided.
5. Replace the thermostat cover.
6. Do not run wire in any location where it might be damaged.
Avoid splicing the thermostat wires unless the spliced wires are
properly cleaned, soldered and taped.
7. Use the 18-gauge wire as supplied for a maximum length of
20-feet. If a longer length is needed, use 16-gauge wire to a
maximum length of 25-feet.
8. Connect the thermostat wires to the control valve as
shown in Figure 17.
FIGURE 17 – THERMOSTAT WIRING

20 COZY TOP VENT GRAVITY GAS WALL HEATER
START-UP PROCEDURE
WARNING: Danger of property damage, bodily injury or
loss of life. propane gas is heavier than air and may settle
in any low area, including open depressions and may
remain there unless area is ventilated. Never attempt
start&up of unit before thoroughly ventilating the area.
Check the furnace operation as outlined in the following
instructions. If any sparking, odors or unusual noises are
encountered, shut off electric power immediately. Recheck for
wiring errors or obstructions in or near fan motor (if equipped).
WARNING: Natural gas heating value (BTU per cubic
foot) can vary significantly. Therefore, it is the installer’s
responsibility to see that BTU/hr. input to the furnace
is adjusted properly. Failure to do so could cause
combustion chamber failure, asphyxiation, fire or
explosion resulting in damage, bodily injury or death.
Refer to the National Fuel Gas Code (NFPA 54) to be
sure the furnace is burning fuel at the proper rate.
CHECK GAS INPUT AND PRESSURES
For furnaces located at elevations between sea level and 2,000
feet, the measured input must not be greater than the input
shown on the nameplate of the furnace. For elevations above
2,000 feet, the measured input must not exceed the input on
the nameplate reduced by 4 percent for each 1,000 feet that the
furnace is above sea level.
Gas supply pressure and manifold pressure with the burner(s)
operating must also be as specified on the nameplate.
Rated input will be obtained on a heating value of 2,500 BTU/
hr. for propane at 10-inches manifold pressure with factory-
sized orifices. If propane gas having a different heating value
is supplied, orifices must be changed by a qualified service
technician before the furnace is operated.
CHECK THE MANIFOLD GAS PRESSURE
A tapped opening is provided in the gas valve to facilitate
measuring manifold gas pressure. A water column manometer
having a scale range from 0 to 12-inches of water column should
be used for this measurement. The manifold pressure must be
measured with the burner and pilot operating. Any major changes
in the flow must be made by changing the size of the burner
orifice.
CHECK THE GAS INPUT (NATURAL GAS ONLY)
Under firing could cause inadequate heat, excessive
condensation or ignition problems. Over firing could cause
shooting flame impingement or overheating of the combustion
chamber. Before starting natural gas input check, obtain the
heating value of gas (BTU per cubic foot) at standard conditions
from your local gas supplier.
To measure the input, using the gas meter, proceed
as follows:
1. Turn off gas supply to all other appliances except
the furnace.
2. With the furnace operating, time the smallest dial on the
meter for one complete revolution. If this is a 2-cubic-
foot dial, divide the seconds by 2. If it is a 1-cubic-foot
dial, use the time in seconds as is. This gives the seconds
per cubic foot of gas being delivered to the furnace.
3. Assuming natural gas with a heating value of 1,000 BTU
per cubic foot and 34-seconds per cubic foot used as
TYPE OF GAS MANIFOLD PRESSURE, IN. W.C.
NATURAL 4.0
PROPANE 10.0
FIGURE 18 – THERMOSTAT MOUNTING PANEL
FACE PANEL-MOUNTED THERMOSTAT INSTALLATION
1. Before removing the face panel, disconnect the
thermostat wires at the gas valve.
2. Locate the knockout on the right side of the furnace
to mount the thermostat. Remove the knockout by
tapping it lightly with a screwdriver Figure 18 It will
also be necessary to cut a 1/2 inch hole in the inside
panel insulation for clearance to the knockout.
3. Cut the thermostat wire to 56 inches.
4. Connect the thermostat wires to terminal screws on
the thermostat base.
5. Feed the thermostat wires through the knockout and
route them through the metal clip to the gas valve.
6. Mount the thermostat to the side of the cabinet with
screws provided.
7. Replace the thermostat cover.
8. Connect the thermostat wires to the control valve as
shown in Figure 17.
IMPORTANT: Keep the thermostat wires away from the
combustion chamber.
INSTALLING YOUR FURNACE