Lochinvar GAS HEATER FOR COMMERICAL POOL APPLICATIONS service manual Combustion Air Inlet Piping

Commercial Pool Heaters

INSTALLATION Continued

Combustion Air Inlet Piping

￿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 Mechanical Room

		Combustion Air Source
Boiler Input	Outside Air*/2 Openings		Outside Air*/1 Opening		Inside Air/2 Openings
500,000	125 in2 (806 cm2)		167 in2 (1077 cm2)		500 in2		(3226 cm2)
650,000	163 in2 (1052 cm2)		217 in2 (1400 cm2)		650 in2		(4194 cm2)
750,000	188 in2 (1213 cm2)		250 in2 (1613 cm2)		750 in2		(4839 cm2)
990,000	248 in2 (1,600cm2)		330 in2 (2,129 cm2)		990 in2		(6,388 cm2)
1,260,000	315 in2	(2,032cm2)	420 in2	(2,710 cm2)	1260 in2		(8,130 cm2)
1,440,000	360 in2	(2,323cm2)	480 in2	(3,097 cm2)	1440 in2		(9,291 cm2)
1,800,000	450 in2	(2,903cm2)	600 in2	(3,871 cm2)	1800 in2 (11,614 cm2)
2,070,000	518 in2	(3,342cm2)	690 in2	(4,452 cm2)	2070 in2	(13,356 cm2)

*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.

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