2.Through the ceiling/roof (see fig.3) or through a sidewall (see fig. 4). Type B-1 vent pipe (inch min. diameter) may be used when venting vertically through the roof, provided a one inch minimum clearance to combustible material is maintained throughout and the vent terminates into a listed wind cap above the roof.
3.Vented freely into the room or space where it is installed, provided that:
a)A Mechanical exhaust system is present in the space where the booster heater is installed.
b)An electrical interlock is provided (by others) so that the booster will not fire if the exhaust system is not providing adequate ventilation to the area.
c)The total BTU input rating of all the unvented gas appliances installed divided by
the total cubic foot volume of the room area (including any adjacent areas that cannot be physically closed off from the installation area) does not exceed 20 BTU’s per hour per cubic foot of space.
For sidewall venting, the booster heater should be located as close as possible to the wall being used. The minimum and maximum wall thickness is determined by the wall thimble available from the vent manufacturer. Refer to the vent manufacturer’s installation instructions.
All horizontal runs of vent pipe must have a minimum rise of 1/4 inch per foot of length and must be supported every 5 feet or less (3 feet in Canada) and at every elbow.
For horizontal venting: The total length of approved 4 inch diameter vent pipe can be a maximum of 40 feet, including two 90 degree elbows and one termination vent. For each elbow above two, reduce the total allowable vent length by ten feet. Minimum horizontal vent length is 2 feet.
For vertical venting: The maximum length of approved 4 inch diameter vent pipe is the same as above; the same requirements for elbows and termination vent apply; the minimum length for vertical venting is 5 feet. An auxiliary power vent kit is available for installations where the vent length must exceed these lengths. Call the factory for assistance. Additional requirements when venting through a sidewall:
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