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Commercial Pool Heaters
Combustion Air Inlet Piping
ƽ WARNING: Locate and install the combustion
air inlet cap 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.
The sidewall or vertical rooftop DirectAire™ combustion air supply
system has specific vent material and installation requirements. The
air inlet pipe connects directly to the pool heater to supply
combustion air. In most installations, the combustion air inlet pipe
will be a dedicated system with one air inlet pipe per pool heater.
You can combine multiple air inlets if the guidelines in Combined
Air Inlet Points, page 13 are followed. The air inlet pipe will be
connected to a combustion air inlet cap as specified in this section.
For normal installations, this system uses a single-wall pipe to
supply combustion air from outdoors directly to the pool heater.
Where overnight temperatures reach 40°F, use a Type-B double-wall
vent pipe or an insulated single-wall pipe for combustion air. This
will help prevent moisture in the cool incoming air from
condensing and leaking from the inlet pipe.
Note:
When the use of the DV box adapter in the following venting
systems is not practical, contact the manufacturer for an “in-line”
filter to address problems.
Length of Air Inlet Pipe
The installed length of air inlet pipe from the pool heater to the
outside air inlet cap must not exceed 50 equivalent feet (15.2m).
Upsizing air inlet pipe diameters is permitted to meet increased
length requirements. Subtract 5 feet (1.5m) of equivalent length
for each 90° elbow. Subtract 2.5 feet (0.7m) of equivalent length for
each 45° elbow.
Do not exceed the limits for the combustion air inlet piping lengths.
Sidewall Air Inlet
The sidewall air inlet cap is supplied in the Horizontal DirectAire™
Vent Kit. Order the kit from the appliance manufacturer. This
sidewall cap supplies combustion air for a single pool heater only.
See TABLE–D, page 17, for kit numbers.
Locate the pool heater as close as possible to the sidewall where you
will install the combustion air supply system.
TABLE-C
Minimum Recommended Combustion Air Supply to Equipment Room
Combustion Air Source
Boiler Input Outside Air*/2 Openings Outside Air*/1 Opening Inside Air/2 Openings
500,000 125 in
2
(806 cm
2
) 167 in
2
(1,077 cm
2
) 500 in
2
(3,226 cm
2
)
650,000 163 in
2
(1,052 cm
2
) 217 in
2
(1,400 cm
2
) 650 in
2
(4,194 cm
2
)
750,000 188 in
2
(1,213 cm
2
) 250 in
2
(1,613 cm
2
) 750 in
2
(4,839 cm
2
)
990,000 248 in
2
(1,600cm
2
) 330 in
2
(2,129 cm
2
) 990 in
2
(6,388 cm
2
)
1,260,000 315 in
2
(2,032cm
2
) 420 in
2
(2,710 cm
2
) 1260 in
2
(8,130 cm
2
)
1,440,000 360 in
2
(2,323cm
2
) 480 in
2
(3,097 cm
2
) 1440 in
2
(9,291 cm
2
)
1,800,000 450 in
2
(2,903cm
2
) 600 in
2
(3,871 cm
2
) 1800 in
2
(11,614 cm
2
)
2,070,000 518 in
2
(3,342cm
2
) 690 in
2
(4,452 cm
2
) 2070 in
2
(13,356 cm
2
)
* Outside air openings shall directly communicate with the outdoors. When combustion air is drawn from the outside through a duct, the net free
area of each of the two openings must have twice (2 times) the free area required for Outside Air/2 Openings. The above requirements are for the
boiler only, additional gas fired units in the boiler room will require an increase in the net free area to supply adequate combustion air for all
units. Combustion air requirements are based on the latest edition of the National Fuel Gas Code, ANSI Z223.1, in Canada refer to CAN/CGA-B149
Installation Code. Check all local code requirements for combustion air.