Section C - Raypak 122-322 Operating And Installation Instructions

SECTION C: COMBUSTION AND VENTILATION AIR
COMBUSTION AND VENTILATION AIR (Indoor Units)
The heater must be supplied with sufficient quantities of non-contaminated air to support proper combustion and equipment
ventilation. Combustion air can be supplied via conventional venting, where combustion air is drawn from the area immedi-
ately surrounding the heater, or via direct vent, where combustion air is drawn directly from outside. All installations must
comply with the requirements of NFGC (U.S.), B 149.1 and .2 (Canada), and all local codes.
CAUTION: Combustion air must not be contaminated by corrosive chemical fumes which can damage the heater
and void the warranty. See appendix A.
DIRECT COMBUSTION AIR
If outside air is drawn through the intake pipe directly to the unit for combustion:
1. Install combustion air direct vent in accordance with Section J of this manual.
CONVENTIONAL COMBUSTION AIR SUPPLY (FOR U.S. INSTALLATION ONLY)
(a) All Air from Inside the Building. The confined space shall be provided with two permanent openings communicating
directly with an additional room(s) of sufficient volume so that the combined volume of all spaces meets the criteria for an
unconfined space. The total input of all gas utilization equipment installed in the combined space shall be considered in
making this determination. Each opening shall have a minimum free area of 1 square inch per 1,000 Btu per hour (22 cm
kW) of the total input rating of all gas utilization equipment in the confined space, but not less than 100 in.² (645 cm
opening shall commence within 12 in. (30 cm) of the top, and one opening shall commence within 12 in. (30 cm) of the bottom,
of the enclosure. The minimum dimension of air openings shall be not less than 3 in. (8 cm) in any direction.
(b) All Air from Outdoors. The confined space shall communicate with the outdoors in accordance with methods 1 or 2. The
minimum dimension of air openings shall not be less than 3 in. (8 cm) in any direction. Where ducts are used, they shall be
of the same cross-sectional area as the free area of the openings to which they connect.
1. Two permanent openings, one commencing within 12in. (30 cm) of the top, and one commencing within 12in. (30 cm)
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 communicate with the outdoors.
a. Where directly communicating with the outdoors or where communicating to the outdoors through vertical ducts,
each opening shall have a minimum free area of 1 sq in. per 4000 Btu per hr (5.5 cm
equipment in the enclosure.
b. Where communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1
sq in. per 2000 Btu per hr (11 cm
2. One permanent opening, commencing within 12 in. (30 cm) of the top of the enclosure, shall be permitted where the
equipment has clearances of at least 1 in. (2.5 cm) from the sides and back and 6 in. (16 cm) from the front of the appliance. The
opening shall directly communicate with the outdoors or shall communicate through a vertical or horizontal duct to the
outdoors or spaces (crawl or attic) that freely communicate with the outdoors, and shall have a minimum free area of:
a. 1 sq in. per 3000 Btu per hr (7 cm
b. Not less than the sum of the areas of all vent connectors in the confined space.
WARNING: Do not use one permanent opening method if the equipment room is under negative
pressure condition or the equipment is common vented with other gas-fired appliances.
2 per kW) of total input rating of all equipment in the enclosure.
2 per kW) of the total input rating of all equipment located in the enclosure, and
11
2 per kW) of total input rating of all
2 per
). One
2