SECTION 8: VENTING
8.11 Outside Combustion Air Supply
IMPORTANT: If the building has a slight negative pressure or corrosive contaminants such as halogenated hydrocarbons are present in the air, an outside combustion air supply to the heater is required. Seal all combustion air pipe joints.
The air supply duct may have to be insulated to prevent condensation on the outer surface. The outside air terminal must not be more than 1' (31 cm) above the vent terminal.
Use of optional outside combustion air is not recommended with unvented heaters.
8.11.1 Length Requirements
Follow the constraints listed on Page 32, Section 8.6.
8.11.2 Vertical Outside Air Supply for Single Heater Installation
SIDE VIEW
Description | Part Number | |
Vent Cap 4" (10 cm) for 80,000 Btu/h | 90502300 | |
and 115,000 Btu/h models | ||
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Vent Cap 5" (13 cm) for 150,000 Btu/h | 90502301 | |
and 200,000 Btu/h models | ||
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8.11.3 Horizontal Outside Air Supply for Single Heater Installation
SIDE VIEW
Vent Cap
Wall
4" (10 cm)
Min.
For 80 and 115 models,
4" (10 cm) Single Wall Pipe. For 150 and 200 models, 5" (13 cm) Single Wall Pipe.
Flex Hose
(Recommended)
Burner |
Band Clamp 
(Recommended)
Description | Part Number | |
Vent Cap 4" (10 cm) for 80,000 Btu/h | 90502300 | |
and 115,000 Btu/h models | ||
| ||
|
| |
Vent Cap 5" (13 cm) for 150,000 Btu/h | 90502301 | |
and 200,000 Btu/h models | ||
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