UHA LOW PROFILE UNIT HEATER INSTALLATION OPERATION AND SERVICE MANUAL
SECTION 6: VENTING
WARNING
Carbon Monoxide Hazard
Heaters may be installed vented or unvented.
Vented heaters must be vented outdoors.
Unvented heaters must be installed in buildings with ventilation rates as per section 6.4.
Failure to follow these instructions can result in death or injury.
6.1 Changing Vent and Air Intake Orientation
The heater is sold with rear horizontal vent and air intake connections as standard (only separated combustion models have air intake connection). If vertical vent and air intake connections are required, follow the instructions on Page 46, Section 14.6.
6.2 Venting
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 NFPA54/ANSI Z223.1 - latest revision, National Fuel Gas Code; Canada: Refer to CSA B149.1 Natural Gas and Propane Installation Code.
Any portion of vent pipe passing through a combustible wall must have a listed thimble to conform with the above codes.
The heater may be installed unvented in certain circumstances according to building ventilation codes. Refer to the above codes and Page 15, Section 6.4 for further information. Unvented operation also requires compliance with the clearances to combustibles given on Page 7, Figure 4.
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.
Vent terminal must be beyond any combustible overhang.
Secure all joints with corrosion resistant #8 x 3/8"
sheet metal screws.
For single wall venting, pressure sensitive aluminum tape or silicone sealant must be used to seal all joints.
Aluminum tape shall have a minimum temperature rating of 400° F (204° C) and meet SMACNA AFTS-
6.2.1 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.
NFPA 54/ANSI Z223.1 - latest revision, National Fuel Gas Code specifies a 4' (1.2 m) horizontal vent terminal clearance from gas and electric meters, regulators and relief equipment.
6.2.2 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
6.3 Vent Installation
Maintain clearences to combustibles at all times for safety. Clearences are the required distances that combustible objects must be away from the heater to prevent serious fire hazard. See Page 7, Figure 4. For vented units, the vent must terminate outside of the building.
Vents must be fully sealed and correctly sized for the model. If the vent passes through a wall or ceiling of combustible material, it must be enclosed by a listed thimble and be separated from the thimble by at least a 2" (5 cm) air gap.
For separated combustion models, vents and air intakes must be a fully sealed system and correctly sized for the model. Vent should be assembled as detailed on Page 17, Figure 9 through Page 20, Figure 14. The joints between the vent terminal and the roof or wall must be properly sealed. If the vent passes through a wall or ceiling of combustible material, it must be enclosed by a listed thimble and be separated from the thimble by at least a 2" (5 cm) air gap.
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