22
This furnace removes both sensible and latent heat from
the combustion gases. Removal of latent heat results in
the condensation of flue gas water vapor. This condensed
water vapor drains from the secondary heat exchanger
and out of the unit into the drain trap.
When installed as a non-direct vent furnace, only exhaust
piping is required and inside combustion air may be used.
Refer to the section on “
NON-DIRECT VENTING
.”
Direct vent installations require a dedicated combustion
air and venting system. All air for combustion is taken
from the outside atmosphere and all combustion products
are discharged to the outdoors.
Adequate facilities for providing air for combustion and
ventilation must be provided in accordance with Section
5.3, “Air for Combustion and Ventilation” of the National
Fuel Gas Code, ANSI Z223.1 (latest edition), in Canada
CSA B149.1; Canadian Natural Gas and Propane Installa-
tion Code and The National Fire Code of Canada, or ap-
plicable provisions for the local building codes, and not
obstructed so as to prevent the flow of air to the furnace.
IMPORTANT:
Air for combustion and ventilation must not
come from a corrosive atmosphere. Any failure due to
corrosive elements in the atmosphere is excluded from
the warranty coverage.
Combustion air must be free of acid-forming chemicals
such as sulfur, fluorine and chlorine. These elements are
found in aerosol sprays, detergents, bleaches, cleaning
solvents, air fresheners, paint and varnish removers, re-
frigerants and many other commercial and household
products. When burned in a gas flame, vapors from these
products form acid compounds. The acid compounds in-
crease the dew point temperature of the flue products and
are highly corrosive after they condense.
The following types of installations (but not limited to the
following) may require outdoor air for combustion (direct
vent) due to chemical exposures:
Commercial buildings
-
Buildings with indoor pools
-
Furnaces installed in laundry rooms
-
Furnaces in hobby or craft rooms
-
Furnaces installed near chemical storage
-
areas
If combustion air is exposed to the following substances
(but not limited to the following), it should not be used and
the furnace may require outdoor air for combustion (direct
vent).
Permanent wave solutions
-
Chlorinated waxes and cleaners
-
Chlorine-based swimming pool chemicals
-
Water softening chemicals
-
De-icing salts or chemicals
-
Carbon tetrachloride
-
Halogen type refrigerants
-
Printing inks, paint removers, varnishes etc.
-
Cleaning solvents (such as perchloroethyl-
-
ene)
Hydrochloric acid
-
Cements and glues
-
Antistatic fabric softeners for clothes dryers
-
Masonry curing and acid washing materials
-
Combustion air requirements are determined by whether
the furnace is in an open (unconfined) area or in a con-
fined space such as a closet or small room.
When the furnace is installed in the same space with
other gas appliances, such as a water heater, be sure
there is an adequate supply of combustion and ventilation
air for the furnace and the other appliances. Do not delete
or reduce the combustion air supply required by the other
gas appliances in this space. See Z223.1, National Fuel
Gas Code (NFPA 54), in Canada CSA B149.1; Canadian
Natural Gas and Propane Installation Code and The Na-
tional Fire Code of Canada, for determining the combus-
tion air requirements for gas appliances. An unconfined
space must have at least 50 cubic feet (volume) for each
1,000 BTUH of the total input of all appliances in the
space. If the open space containing the appliances is in a
building with tight construction (contemporary construc-
tion), outside air may still be required for the appliances to
burn and vent properly. Outside air openings should be
sized the same as for a confined space.
VENTING & COMBUSTION AIR REQUIREMENTS
GENERAL VENTING REQUIREMENTS AND
GUIDELINES
!
WARNING
READ AND FOLLOW ALL INSTRUCTIONS IN THIS
SECTION. FAILURE TO PROPERLY VENT THIS
FURNACE CAN CAUSE CARBON MONOXIDE POI-
SONING, OR AN EXPLOSION OR FIRE, RESULT-
ING IN PROPERTY DAMAGE, PERSONAL INJURY
OR DEATH.
!
WARNING
ALL FURNACE INSTALLATIONS MUST COMPLY
WITH THE NATIONAL FUEL GAS CODE, IN
CANADA CSA B149.
1; CANADIAN NATURAL GAS
AND PROPANE INSTALLATION CODE AND THE NA-
TIONAL FIRE CODE OF CANADA,
NFPA 54
AND
LOCA
L CODES TO PROVIDE ADEQUATE COMBUS-
TION AND VENTILATION AIR FOR THE FURNACE.
FAILURE TO DO SO CAN RESULT IN EXPLOSION,
FIRE, PROPERTY DAMAGE, CARBON MONOXIDE
POISONING, PERSONAL INJURY OR DEATH.
!
WARNING
THIS FURNACE AND ANY OTHER FUEL-BURNING
APPLIANCE MUST BE PROVIDED WITH ENOUGH
FRESH AIR FOR PROPER COMBUSTION AND
VENTILATION OF THE FLUE GASES. MOST
BUILDINGS WILL REQUIRE THAT OUTSIDE AIR BE
SUPPLIED INTO THE FURNACE AREA. FAILURE
TO DO SO CAN CAUSE PERSONAL INJURY OR
DEATH FROM CARBON MONOXIDE POISONING.
REFER TO SECTION TITLED “
NON-DIRECT VENT-
ING
” TO DETERMINE IF THE FURNACE MUST USE
OUTSIDE AIR FOR COMBUSTION.
Ve
nt
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