Commercial Pool Heaters
INSTALLATION Continued
2.On horizontal runs, do not install vent pipe with seams pointing down. Position vent pipe so that the seams are on the top side of the vent pipe.
3.Secure all joints with a minimum of three sheet metal screws or pop rivets. Apply aluminum foil duct tape or silicone sealant to all screws or rivets installed in the vent pipe.
4.Ensure that the air inlet pipes are properly supported.
WARNING: Properly seal all joints and seams in the inlet vent piping system. Failure to do so may result in flue gas recirculation, spillage of flue products, and carbon monoxide emissions. Carbon monoxide poisoning can cause severe personal injury or death.
Combined Combustion Air Inlet Points
You can combine the air inlet pipes from multiple pool heaters to a single common connection if the common air inlet pipe has a cross sectional area equal to or larger than the total area of all air inlet pipes connected to the common air inlet pipe.
Example: Two 8" (20.3cm) air inlet pipes (50.3 in2 [324.5cm2] area each) have a total area of 100.6 in2 (645.2cm2), requiring a 12" (30.5cm) (113.1 in2 [729.7cm2]) common air inlet pipe.
The air inlet point for multiple pool heater air inlets must be provided with an exterior opening which has a free area equal to or greater than the total area of all air inlet pipes connected to the common air inlet. This exterior opening for combustion air must connect directly to the outdoors. The total length of the combined air inlet pipe must not exceed a maximum of 50 (15.2m) equivalent feet. You must deduct the restriction in area provided by any screens, grills, or louvers installed in the common air inlet openings and some rooftop terminations. Screens, grills, or louvers installed in the common air inlet can reduce the free area of the opening from 25% to 75% based on the materials used.
Vertical and Sidewall Combustion Air Inlet
IMPORTANT: To prevent recirculation of flue products into the combustion air inlet, follow all instructions in this section.
WARNING: Locate and install the combustion air inlet termination correctly. Failure to do so can allow the discharge of flue products to be drawn into the combustion process. This can result in incomplete combustion and potentially hazardous levels of carbon monoxide in the flue products. This will cause operational problems and the spillage of flue products. Spillage of flue products can cause personal injury or death due to carbon monoxide poisoning.
You must locate the combustion air cap and the flue gas outlet on the same rooftop surface (vertical direct vent system) or sidewall surface (horizontal direct vent system) and in the same pressure zone as the vent termination. Follow all clearance requirements listed on pages 8 and 9.
Purchase and assemble the combustion air inlet cap to protect the air inlet from wind and weather.
Alternatively, assemble the combustion air inlet cap for the vertical rooftop air inlet from items purchased locally. The air inlet cap consists of two 90° elbows installed to the air inlet pipe (see Figure 26). Install the first 90° elbow on the rooftop at the highest vertical point of the air inlet pipe. Install the second 90° elbow on the horizontal outlet of the first elbow. The outlet of the second 90° elbow will be pointing down. You may use a 90° elbow and a 90° street elbow to make this assembly. If you use a straight piece of pipe between the two 90° elbows, it should not exceed 6" (51mm) in length.
Figure 26 – Vertical Rooftop Air Inlet
For horizontal direct vent termination of combustion air, you must use the termination cap from the pool heater manufacturer. The sidewall air inlet cap is available as part of a direct vent kit. See
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