The new heater, which is certified for indoor use, was placed on the basement’s north wall to allow ventilation through the concrete foundation and kept the vent stack and gas service out of view from the outside of the building. Further, the unit has a sealed combustion chamber with supply air ducting directly to the heater and direct power venting to the outdoors.
Venting requirements for new heaters are quite different from what was required in the past. Although this process has become easier, the importance of proper venting is still critical. Improper installation and/or operation could result in insufficient venting of carbon monoxide gas and/or flue gases that could cause serious injury.
When venting heaters, it is important to maintain proper clearances (152 mm [6 in.]) from combustible surfaces on the top and side of the unit. When considering requirements with respect to how far a heater can be vented, or how far ductwork can run to pull intake air, each 90-degree elbow reduces the maximum horizontal polyvinyl chloride (PVC) air intake run by 3.6 m (12 ft). Each 45-degree elbow reduces the maximum run by 1.8 m (6 ft).
The minimum requirements for air supply specify the equipment room in which a heater is installed to be equipped with two permanent air supply openings: one commencing within 305 mm (12 in.) of the top and one commencing within 305 mm (12 in.) from the bottom of the enclosure for combustion air.
This installation procedure is in accordance with American National Standards Institute (ANSI) Z223.1, National Fuel Gas code, Canadian Standards Association (CSA) B149.1, Natural Gas and Propane Installation codes, as applicable, and any local codes that may apply.
Air supply openings should directly, or through a duct, connect to outdoor air. Therefore, for this particular installation, the heater was tested for a direct-air intake duct using 102-mm (4-in.) PVC pipe and separate vent pipes were installed. In the past, venting and air intake ducts had to be in balance and be the same length; however with these new heaters, they draw combustible air from outside the structure and flue gases are forced out.
The colour of the heater’s flame is a good indicator of whether or not the unit is receiving enough combustible air to function properly. A flame that is blue and clear indicates the unit is burning 100 per cent of the gas. If the flame is not getting enough air, it becomes orange and releases carbon that turns to soot and clogs heat exchangers.
One of the more common mistakes that occur when installing a new heater is upgrading the size of the unit without having a large enough supply of gas. For example, if the pool previously had a gas line for a 200,000-Btu heater and the new unit is rated 400,000 Btus, the gas line also needs to be bigger to accommodate the increased output.
