Installing the water heater.
Inspect Shipment
Inspect the water heater for possible damage. Check the markings on the rating plate of the water heater to be certain the type of gas supplied corresponds to the water heater requirements.
Combustion and Ventilation Air
CAUTION: For COMMERCIAL models ONLY - Large exhaust fans can lower the air pressure inside a building or room and interfere with proper venting and operation. Commercial kitchens or other locations that must maintain a high flow of exhaust air should have the water heater installed in a separate room with combustion and ventilation air supplied directly from outside as described to the right.
Proper operation of the water heater requires air for combustion and ventilation. Provisions for combustion and ventilation air must comply with referenced codes and standards.
NOTICE: If the water heater 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 water heater is installed in a confined space, provisions for combustion and ventilation air must be made.
A confined space is one having a volume of less than 50 cubic feet (1.4 cubic metres) per 1000 Btuh of the aggregate input of all appliances within that space.
The air must be supplied through two permanent openings of equal area. One is to be located within 12” (30.5cm) above the floor and the other is to be located within 12” (30.5cm) from the ceiling.
The minimum net free area of each opening must not be less than one square inch (6.5sq. cm) per 1000 Btuh of the total input rating of all the appliances in the enclosure (but not less than 100 square inches (650sq cm)), if each opening communicates with other unconfined areas inside the building.
Buildings of unusually tight construction shall 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 located as specified above and each must have a minimum net free area of not less than one square inch
(6.5sq. cm) per 1000 Btuh of the total input rating of all the appliances in the enclosure.
If horizontal ducts are used to communicate with the outdoors, each opening must have a minimum net free area of not less than one square inch (6.5sq. cm) per 2000 Btuh of the total input rating of all the appliances in the enclosure. If ducts are used, the minimum dimensions of rectangular air ducts shall not be less than 3” (7.62cm).
NOTICE: If the duct openings which supply combustion and ventilation air are to be covered with a protective screen or grill, the net free area (openings in the material) of the covering material must be used in determining the size of the openings. Protective screening for the openings MUST NOT be smaller than 1/4” (0.64cm) mesh to prevent clogging by lint or other debris.
NOTICE: The water heater should not be installed near an air supply containing halogenated hydrocarbons.
Corrosive Atmospheres
The air in beauty shops, dry cleaning establishments, photo processing labs, and storage areas for liquid and powdered bleaches or swimming pool chemicals often contain such halogenated hydrocarbons.
An air supply containing halogenated hydrocarbons may be safe to breathe, but when it passes through a gas flame corrosive elements are released that will shorten the life of any gas burning appliance.
Propellants from common spray cans or gas leaks from A/C and refrigeration equipment are highly corrosive after passing through a flame.
The water heater warranty is voided when failure of the heater is due to operation in a corrosive atmosphere.
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