Raypak 992B manual Water Piping, Canadian Installations, General, Reversing Water Connections

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 the outdoors. The total cross-sectional area of such an opening(s) shall be at least 10% of the area required in 2. and 3. (below), but in no case shall the cross-sectional area be less than 10 in.2 (65 cm2).

2.For heaters using a barometric damper in the vent system there shall be a permanent air supply opening(s) having a cross section area of not less than 1 in.2 per 7,000 BTUH (320 mm2 per kW) up to and including 1 million BTUH, plus 1 in.2 per 14,000 BTUH (160 mm2 per kW) in excess of 1 million BTUH. This opening(s) shall be either located at or ducted to a point not more than 18 in. (450 mm) nor less than 6 in. (152 mm) above the floor level. The duct can also “goose neck” through the roof. The duct is preferred to be straight down and terminated 18 in. (450 mm) from the floor, but not near piping. This air supply opening require- ment shall be in addition to the air opening for ventilation air required in 1. (above).

WARNING: Care must be taken to ensure that the equipment room is not under negative pressure conditions or that the equipment is not common- vented with other gas-fired appliances.

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 in.2 for each 30,000 BTUH mm2 per kW) of total rated input of the burner(s), and the location of the opening(s) shall not interfere with the intended purpose of the opening(s) for ventilation air referred to in (1). This opening(s) can be ducted to a point not more than 18 in. (450

mm) nor less than 6 in. (152 mm) above the floor level. The duct can also “goose neck” through the roof. The duct is preferred to be straight down 18 in. (450 mm) from the floor, but not near piping.

4.Refer to B149 Installation code for additional infor- mation.

Water Piping

NOTE: For 87%-efficiency boilers, see special instructions on page 45.

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 G and Table H 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.

NOTE: Minimum pipe size for in/out connections is 2 1⁄2 in. Verify proper flow rates and ΔT as instructed in this manual.

Reversing Water Connections

Follow these instructions to change the water connec- tions from the left-hand side (standard) to the right-hand side.

1.Disconnect all electrical power from the heater (if applicable).

2.Label all electrical connections and conduit lines. This may include the flow switch, low water cut-off probe and/or pump.

3.Disconnect or isolate the main gas pipe from the heater (if applicable).

4.Remove both in/out and return header access panels by removing all sheet metal screws.

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