SECTION 8: VENTING
WARNING
Carbon Monoxide Hazard
Heaters installed unvented must be interlocked with sufficient building exhaust.
Heaters must be installed according to the installation manual.
Failure to follow these instructions can result in death or injury.
WARNING
Cut/Pinch Hazard
Wear protective gear during installation, operation and service.
Edges are sharp.
Failure to follow these instructions can result in injury.
8.1 General Venting Requirements
This heater must be vented in accordance with the rules contained in this manual and with the following national codes and any state, provincial or local codes which may apply:
United States: Refer to National Fuel Gas Code NFPA 54/ANSI Z223.1 - latest revision.
Canada: Refer to Natural Gas and Propane Installation Code CSA B149.1 - latest revision.
Exhaust end of heater will accept a 4' (10 cm) vent pipe using the vent adapter (P/N 90502700). To prevent leakage of condensation, install the vent adapter with the seam on top and seal the joint using a high temperature silicone sealant.
Any portion of vent pipe passing through a combustible wall must have an approved thimble to conform with the above listed codes.
Vent pipe must be sloped downward away from the burner 1/2'' (1 cm) for every 20' (6 m).
The heater may be individually vented or common vented. When venting horizontally, a maximum of two heaters can be commonly vented. See Page 36, Section 8.9. When venting vertically, a maximum of four heaters can be commonly vented. See Page 37, Section 8.10.
The heater may also be installed unvented in certain circumstances according to building ventilation codes. Refer to the above codes and Page 34, Section 8.2 for further information. Unvented operation also requires compliance with the clearances to combustibles given on Page 8, Figure 12.
The bottom of the vent or air intake terminal shall not be located less than 1' (.3 m) above grade level.
The vent shall not terminate less than 7' (2.1 m) above grade where located adjacent to public walkways.
Vent terminal must be installed at a height sufficient to prevent blockage by snow and building materials protected from degradation by flue gasses.
Secure all joints with #8 x 3/8 sheet metal screws. Seal all joints with high temperature silicone sealant.
Vent terminal must be beyond any combustible overhang.
8.1.1 United States Requirements
Vent must terminate at least 3' (.9 m) above any forced air inlet located within 10' (3.1 m).
Vent must terminate at least 4' (1.2 m) below, 4'
(1.2 m) horizontally from, or 1' (.3 m) above any door, operable window, or gravity air inlet into any building.
8.1.2 Canadian Requirements
The vent shall not terminate within 6' (1.8 m) of a mechanical air supply inlet to any building.
The vent shall not terminate within 3' (.9 m) of a
window or door that can be opened in any building, any
8.2 Unvented Operation
Sufficient ventilation must be provided in the amount of 4 cfm per 1000 Btu/h firing rate (United States); 3 cfm per 1000 Btu/h firing rate (Canada).
Use of optional outside combustion air is not recommended with unvented heaters.
If exhaust fans are used to supply ventilation air, an interlock switch must be used to prevent the heater from coming on when the fans are off. This may be done using a pressure switch.
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