Raypak 122-322 manual Water Piping, Canadian Installations, General, Relief Valve Piping

Btu per hr (11 cm2 per kW) of total input rating of all equipment in the enclosure.

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 out- doors 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 cm2 per kW) of the total input rating of all equipment located in the enclosure, and

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 conditions or the equipment is common vented with other gas-fired appliances.

Canadian Installations

CAUTION: All combustion air must be drawn from the air outside of the building; the mechanical equip- ment room must communicate directly with the outdoors.

1.Ventilation of the space occupied by the heater shall be provided by an opening(s) for ventilation air at the highest practical point communicating with outdoors. The total cross-sectional area of such an opening(s) shall be at least 10% of the area required in (2) and (3), but in no case shall the cross-sectional area be less than 10 sq. in. (6500 sq. mm.).

2.For heaters using a barometric damper in the vent system, and when air supply is provided by natu- ral air flow from the outdoors for natural draft, partial fan assisted, fan-assisted or power draft- assisted burners, there shall be a permanent air supply opening(s) having a cross section area of not less than 1 sq. in. per 7000 BTUH (310 sq. mm per kW) up to and including 1 million BTUH, plus 1 sq. in. per 14000 BTUH (155 sq. mm per kW) in excess of 1 million BTUH. This opening(s) shall be either located at or ducted to a point neither more

than 18 in. (450 mm) nor less than 6 in. (150 mm) above the floor level. The duct can also "Goose Neck" through the roof. The duct is preferred straight down 18” from floor, but do not place near piping. This air supply opening requirement shall be in addition to the air opening for ventilation air required in (1).

3.For heaters not using a barometric damper in the vent system, and when air supply is provided by natural air flow from outdoors for a power burner and there is no draft regulator, drafthood or similar flue gas dilution device installed in the same space, in addition to the opening for ventilation air required in (1), there shall be a permanent air sup- ply opening(s) having a total cross-sectional area of not less than 1 sq. in. for each 30,000 BTUH (70 sq. mm per kW) of total rated input of the burn- er(s), and the location of the opening(s) shall not interfere with the intended purpose of the open- ing(s) for ventilation air referred to (1). This opening(s) can be ducted to a point neither more than 18 in. (450 mm) nor less than 6 in. (150 mm) above the floor level. The duct can also "Goose Neck" through the roof. The duct is preferred to be straight down 18” from floor, but do not place near piping.

4.Refer to the latest version of the B149 for addition- al information.

Water Piping

General

The heater should be located so that any water leaks will not cause damage to the adjacent area or struc- tures.

CAUTION: This heater requires forced water circulation when the burner is operating. See Table F and Table G for minimum and maximum flow rates and water pump selection. The pump must be interlocked with the heater to prevent heater operation without water circulation.

Relief Valve Piping

WARNING: Pressure relief valve discharge piping must be piped near the floor and close to a drain to eliminate the potential of severe burns. Do not pipe to any area where freezing could occur. Refer to local codes.

12