Lochinvar CF-CH(E)-i&s-08, 999 - 750, 399 Combustion Air Inlet Piping, Length of Air Inlet Pipe

Installation and Service Manual

TABLE - B

Flue and Air Inlet Pipe Sizes

Input	Flue	Air Inlet
Btu/hr	Size	Size*
399,999	6"	6"
500,000	6"	6"
650,000	8"	8"
750,000	8"	8"
990,000	10"	10"
1,260,000	12"	12"
1,440,000	12"	12"
1,800,000	14"	12"
2,070,000	14"	12"

*Minimum diameter for air inlet pipe. Installer may increase diameter one pipe size for ease of installation, if needed.

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 unit to supply combustion air. In most installations, the combustion air inlet pipe will be a dedicated system with one air inlet pipe per unit. You can combine multiple air inlets if the guidelines in Combined Air Inlet Points, page 15 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 unit.

In cold climates, 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.

Length of Air Inlet Pipe

The installed length of air inlet pipe from the unit to the outside air inlet cap must not exceed 50 equivalent feet (15.2m). 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 unit only. See TABLE–D, page 19, for kit numbers.

Locate the unit as close as possible to the sidewall where you will install the combustion air supply system.

FIG. 14 Sidewall Combustion Air Inlet

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