Raypak 300, 850 Conventional Combustion Air Supply, Combustion Air Filter, Direct Vent

Combustion Air Filter

This heater is supplied with an integral combustion air filter. This filter will reduce the amount of particulates that pass through the combustion system and heat exchanger but will not protect against chemical inside air contamination (See Appendix). The filter must be checked periodically to verify that adequate combus- tion air is being supplied to the heater. See the Maintenance section of this manual for information on checking the filter and establishing service intervals.

Direct Vent

If outside air is drawn through the intake pipe directly to the unit for combustion:

1.Install the combustion air ducting kit.

2.Install combustion air direct vent in accordance with Fig. 23 (horizontal) or Fig. 24 (vertical) of this manual.

3.Provide adequate ventilation of the space occu- pied by the heater(s) by an opening(s) for ventilation air at the highest practical point com- municating with the outdoors. The total cross-sectional area shall be at least 1 in.2 of free area per 20,000 BTUH (111 mm2 per kW) of total input rating of all equipment in the room when the opening is communicating directly with the out- doors or through vertical duct(s). The total cross-sectional area shall be at least 1 in.2 of free area per 10,000 BTUH (222 mm2 per kW) of total input rating of all equipment in the room when the opening is communicating with the outdoors through horizontal duct(s).

4.In cold climates, and to mitigate potential freeze- up, Raypak highly recommends the installation of a motorized sealed damper on the air intake to prevent the circulation of cold air through the heater during the non-operating hours.

TruSeal™ Combustion Air

In addition to the 4 previous steps, combustion air may be ducted directly to the heater by using PVC, CPVC or sealed single-wall galvanized ducting. The duct will attach directly to the air collar located on the rear of the heater when the combustion air ducting kit is installed, using three or four sheet metal screws (not supplied) equally positioned around the circumference of the duct. The screws and duct connection point must be sealed with RTV (not supplied). TruSeal is generally used when damaging contaminants are present in the

mechanical room. All ducting must be self-supported. CAUTION: Use TruSeal combustion air if damaging airborne contaminants are or may be present in the boiler area. See the Appendix of this manual regarding air contamination.

Conventional Combustion Air Supply

U.S. Installations

All Air from Inside the Building

The confined space shall be provided with TWO per- manent openings communicating directly with an additional room(s) of sufficient volume so that the com- bined volume of all spaces meets the criteria for a room large in comparison (NFGC). The total input of all gas utilization equipment installed in the combined space shall be considered in making this determina- tion. Each opening shall have a minimum free area of 1 in.2 per 1,000 BTUH (2,225 mm2 per kW) of the total input rating of all gas utilization equipment in the con- fined space, but not less than 100 in.2 (645 cm2). One opening shall commence within 12 in. (305 mm) of the top, and one opening shall commence within 12 in. (305 mm) of the bottom of the enclosure. The mini- mum dimension of air openings shall be not less than 3 in. (76 mm) in any direction.

All Air from Outdoors

The confined space shall communicate with the out- doors in accordance with one of the methods below. The minimum dimension of air openings shall not be less than 3 in. (76 mm) in any direction. Where ducts are used, they shall be of the same cross-sectional area as the net free area of the openings to which they connect.

1.Two permanent openings, one commencing within 12 in. (305 mm) of the top, and one com- mencing within 12 in. (305 mm) of the bottom of the enclosure, shall be provided. The openings shall communicate directly, or by ducts, with the outdoors or spaces (crawl or attic) that freely com- municate with the outdoors.

a.Where directly communicating with the out- doors or where communicating to the outdoors through vertical ducts, each open- ing shall have a minimum free area of 1 in.2 per 4,000 BTUH (550 mm2 per kW) of total input rating of all equipment in the enclosure.

11