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10
Combustion Air
Caution:
Air for combustion must not be contaminated by halogenated hydrocarbons, which include fluoride,
chloride, bromides and iodide. These elements are found in aerosol sprays, detergents, bleaches,
cleaning solvents, salts, air fresheners, and other household products. Humidifier warranty is voided
when failure of gas equipment is due to operation in a corrosive atmosphere.
Caution:
If the humidifier is installed in an unconfined space within a building of conventional frame, masonry
or metal construction, infiltration air is normally adequate for proper combustion and ventilation. If
the humidifier is installed in a confined space provisions for combustion air must be made. Any
ventilation equipment located in immediate proximity of the humidifier could cause a negative
pressure condition at the humidifier. Appropriate make-up air must be supplied to compensate for all
other ventilation equipment in addition to that required by the humidifier.
Proper operation of the Series GFH requires air for combustion and ventilation. Provisions for combustion
and ventilation air must comply with Section 5.3, Air for Combustion and Ventilation, of the National Fuel Gas
Code, ANSI Z223.1-1988, or acceptable provisions for the local building codes. Canadian installations must
be installed in accordance with sections 7.2, 7.3 and 7.4 of the CAN/CGA.B149 Installation Codes, and all
authorities having jurisdiction.
Do not
block or obstruct any openings on the appliance, spaces around the appliance, or air openings
adjacent to the appliance area.
Do not
block the flow of combustion or ventilation air. Openings must be provided for necessary combustion
air to enter the area where the humidifier is located from an outside source. Any enclosed space, such as
mechanical rooms, must be ventilated to provide the proper supply of fresh air for burner combustion. The
size of the opening is dependent upon the rating of the burner.
Sealed Combustion Air
All models in the GFH family will be capable of sealed combustion with the installation of the sealed
combustion kit. This kit will facilitate combustion air being drawn thru 4” PVC pipe for a distance up to 40
feet equivalent piping from an outdoor air source.
A confined space is one having a volume of less than 50 cubic feet per 1000 BTU/hr of the aggregate
input of all appliances within that space.
The air is to be supplied by two equal size openings, one within 12” below the ceiling, and one within 12”
above the floor.
An opening must be provided not less than one square inch per 1000 BTU/hr of the total input rating of all
the appliances sharing the enclosure. The minimum opening is to be 100 square inches.
Buildings of unusually tight construction must have the combustion and ventilation air supplied from
outdoors, or a freely ventilated attic or crawl space.
If air is supplied from outdoors, directly or through vertical ducts, there must be two openings sized at not
less than 1 square inch per 4000 BTU/hr of total input rating of all appliances sharing the enclosure.
If horizontal ducts are to be used, each opening must be sized at not less than 1 square inch per 2000
BTU/hr of the total input rating of all the appliances sharing the enclosure.
If the duct openings are to be covered with a protective screen or grill, the mesh will not be smaller than
¼” to prevent clogging by lint or other debris.
