FURNACE VENTING
DEFINITIONS
"Vent" and "Chimney" refer to open passageways that convey vent gases from the furnace, or its vent connector, to the outside. Vents and chimneys usually run vertically or nearly vertically. When they serve only one gas appliance, they are called "dedicated" vents or chimneys. When they serve multiple gas appliances, they are called "common" vents or chimneys.
"Vent Connector" refers to a pipe or duct that connects the furnace to a vent or chimney. Vent connectors usually run from the furnace’s vent collar to the vent or chimney. Vent connectors may have vertical and horizontal runs.
"Venting System" refers to a continuous open passageway from the vent collar to the outside. Venting systems usually have a vent connector(s) and a vent or chimney. Venting systems commonly serve a single furnace, or a single furnace and a hot water heater. Other multiple appliance venting systems are less common.
"Fan Assisted Combustion System" refers to an appliance equipped with an integral mechanical means to either draw or force products of combustion through the combustion chamber and/or heat exchanger. This series furnace uses a draft inducer to draw combustion products through the heat exchanger and is considered to have a fan assisted combustion system. Category I furnaces with fan assisted combustion systems must not be vented into single wall metal vents.
DESIGN CONSIDERATIONS
The furnace is design certified as a Category I appliance, which means that the furnace relies on the buoyancy of combustion products to vent properly. Since buoyancy decreases proportionately with temperature, the chimney size and properties are very important. An oversized chimney, or one that is exposed to the cold will not maintain the required buoyancy as well as it should, and may allow excessive condensation to form.
IMPORTANT: Do not common vent the furnace with Cate- gory III or IV
The furnace must be vented in accordance with these instructions, the Venting Tables and rules published in the current editions of ANSI Z223.1 / NFPA 54, National Fuel Gas Code in the United States, or B149, Natural Gas and Propane Installation Code in Canada, and within the requirements of the codes of the local authority having jurisdiction.
Refer to section 5.3 of ANSI Z2213.1/NFPA 54 or sections 7.2, 7.3 or 7.4 of CSA B149 for venting requirements.
The furnace is not equipped with a draft hood to introduce dilution air to the chimney. The products of combustion will therefore have a higher concentration of water vapor within them. If the furnace is the only appliance served by the chimney, a tiled masonry chimney, regardless of tile size, must not be used without a suitably sized certified chimney liner and termination. Consider dedicated venting with a B Vent used as a liner in this case. See Dedicated Venting on page 11.
Multistory and common venting with other Category I gas fired appliances is permitted. The venting system must be in accordance with the National Gas Code, B149 in Canada, ANSI Z223.1/NFPA 54 in the United States, local codes, and approved engineering practices.
WARM AIR FURNACE
CAUTION
Combustion air must be free of acid forming chemicals such as sulphur, fluorine and chlorine. These elements are found in aerosol sprays, detergents, bleaches, cleaning solvents, air fresheners, paint and varnish removers, refrigerants, and many other commercial and household products.
When burned in a gas flame, vapors from these products form acid compounds. Acid compounds increase the dew point temperature of the flue products and are highly corrosive after they condense.
Any furnace failure caused by corrosive elements is excluded from warranty coverage.
The following types of installation sites (but not limited to the following) will require OUTDOOR AIR for combustion because of chemical exposures: commercial buildings, buildings with indoor swimming pools, furnaces installed in laundry rooms, furnaces in hobby or craft rooms, furnaces installed near chemical storage areas.
Exposure to the following substances in the combustion air supply (but not limited to the following) will also require OUTDOOR AIR for combustion:
•Aerosols, particularly CFC based or propelled aerosols
•Air fresheners
•Airplane Glue and similar adhesives and cements
•Ammonia, as commonly found in permanent wave solutions used in hair dressing salons
•Antistatic fabric softeners used in clothes dryers
•Carbon tetrachloride
•Chlorinated cleaners and waxes
•Chlorine and bromine based swimming pool chemicals
•Deicing salts or chemicals, e.g. rock salt, etc.
•Dry cleaning fluids such as perchloroethylene
•Fumes from curing polyurethane and similar substances
•Halogen based refrigerants including
•Hydrochloric acid, muriatic acid and other acid based masonry washing and curing materials
•Printer’s inks, paint removers, varnishes, varsol, toluene, etc.
•Water softener salt and chemicals
WARNING
SELECT APPROPRIATE VENTING MATERIALS AND ENSURE PROPER CLEARANCES TO COMBUSTIBLES. INADEQUATE VENTING OR FAILURE TO MAINTAIN PROPER CLEARANCES TO COMBUSTIBLES MAY ALLOW THE ACCUMULATION OF THE PRODUCTS OF COMBUSTION WITHIN THE BUILDING RESULTING IN FIRE, NAUSEA, OR ASPHYXIATION.
DO NOT USE AN UNLINED MASONRY CHIMNEY TO VENT THIS FURNACE. THE USE OF AN UNLINED MASONRY CHIMNEY INCREASES THE RISK OF CONDENSATE FORMATION, WHICH MAY CAUSE THE CHIMNEY TO DETERIORATE, ALLOWING COMBUSTION PRODUCTS AND CONDENSATE TO COLLECT IN THE BUILDING.
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