Installation and Service Manual
Figure 7 – Outside Combustion Air - Two Openings
2. Outside Combustion Air, Using Ducts
You can direct outside combustion air to this pool heater using two air ducts to deliver the air to the mechanical room. Each of the two openings must have a minimum free area of one square inch per 2000 Btu input (11cm2 per kW).
Figure 8 – Outside Combustion Air Through Ducts
3. Outside Combustion Air, Using Direct Venting
With this option, you can connect combustion air vent piping directly to the pool heater. See the information under Direct Venting starting on page 21 for specific information regarding this option.
4. Combustion Air from Interior Space
You can direct combustion air to this pool heater using air from an adjoining interior space. You must provide two openings from the mechanical room to the adjoining room.
Each of the two openings must have a net free area of one square inch per 1000 Btu input (22cm2 per kW), but not less than 100 square inches (645cm2).
Figure 9 – Combustion Air from Interior Space
All dimensions are based on net free area in square inches. Metal louvers or screens reduce the free area of a combustion air opening a minimum of approximately 25%. Check with louver manufacturers for exact net free area of louvers. Where two openings are provided, one must be within 12" (30 cm) of the ceiling and one must be within 12" (30 cm) of the floor of the mechanical room. Each opening must have a minimum net free area as specified in
The combustion air supply must be completely free of any flammable vapors that may ignite or chemical fumes which may be corrosive to the pool heater. Common corrosive chemical fumes which must be avoided are fluorocarbons and other halogenated compounds, most commonly present as refrigerants or solvents, such as Freon, trichlorethylene, perchlorethylene, chlorine, etc. These chemicals, when burned, form acids which quickly attack the heat exchanger finned tubes, headers, flue collectors, and the vent system. The result is improper combustion and a
Exhaust Fans
Any fan or equipment which exhausts air from the mechanical room may deplete the combustion air supply and/or cause a downdraft in the venting system. Spillage of flue products from the venting system into an occupied living space can cause a very hazardous condition that must be immediately corrected. If a fan is used to supply combustion air to the mechanical room, the installer must make sure that it does not cause drafts which could lead to nuisance operational problems with the pool heater.
Vertical DirectAire™ and Horizontal DirectAire™ venting systems have specific requirements for combustion air ducts from the outside which are directly connected to the pool heater. See the requirements for combustion air duct in the venting section starting on page 12.
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