Operating instructions
22
WARNING
Vent extending through exterior wall shall not 
terminate adjacent to wall or below building 
extensions such as eaves, balconies, parapets or 
decks. Failure to comply could result in death or 
serious injury.
! 
6.4 Vent Pipe Installation
• Minimum and maximum combustion air and vent pipe 
lengths listed in Table 5. Pipe length counted from 
combustion air connector to termination.
• Install eld-sourced 2" to 3" transition, if used, in vertical 
section at combustion air inlet and vent connector.
• 90° elbows equivalent to 5.0 ft (1.6 m). 45° elbows 
equivalent to 3.5 ft (1.1 m). 2" to 3" transition has no 
equivalent length. See Table 6.
• Use exible Polyproplyene piping (PP) in a vertical 
position only. Check PP pipe manufacturer for details. 
Each foot of PP exible pipe is equivalent to 2⅝ feet of 
smooth pipe of same diameter.
• Slope vent pipes minimum 1/4" per foot (21 mm/m) 
back toward boiler. Support horizontal sections to 
prevent sags capable of accumulating condensate.
• Support piping in accordance with pipe manufacturer's 
instruction and authority having jurisdiction. In absence 
of manufacturer's instruction use pipe hooks, pipe 
straps, brackets, or hangers of adequate and strength 
located at intervals of 4 ft (1.2m) or less. Allow for 
expansion/contraction of pipe. 
• Combustion air and vent piping must be air tight and 
water tight.
• Certied vent system components must NOT be 
interchanged with other vent systems or unlisted pipe/
ttings.
• Canadian installations only. All venting material, primer 
and glue must be listed to ULC S636.
• Canadian installations only. First 3 ft (0.9 m) of 
plastic vent pipe from vent connector must be readily 
accessible for visual inspection.
6.5 Vent Termination
• Terminate combustion air and vent pipes with ttings or 
concentric vent kit.
A.  See "Parts, Kits and Optional Accessories" manual 
for concentric vent kit part numbers. 
B.  Use horizontal pipe for vent and 90° elbow for 
combustion air termination when using ttings.
• Terminate combustion air and vent pipes in same 
atmospheric pressure zone through exterior sidewall or 
roof.
• Locate combustion air termination as far as possible 
from swimming pool, swimming pool pump house, and 
other sources of airborne chlorine.
• Locate combustion air and vent terminals as required by 
authority having jurisdiction. 
Minimum/Maximum Vent Lengths
2” Pipe  3” Pipe 4” Pipe
Model 050 075/100 075/100 150/200 299 299
Min.
6 ft. 
(1.8 m)
6 ft. 
(1.8 m)
6 ft. 
(1.8 m)
6 ft. 
(1.8 m)
6 ft. 
(1.8 m)
6 ft. 
(1.8 m)
Max.
100 ft. 
(30.5 m)
50 ft. 
(15.2 m)
100 ft. 
(30.5 m)
100 ft. 
(30.5 m)
25 ft. 
(7.7 m)
100 ft. 
(30.5 m)
Table 5 - Combustion Air and Vent Piping Length
For Example: Boiler can be installed on outside wall and vented with one 90° elbow and 1 ft (0.30 m) of vent pipe.
Table 6 -Equivalent Length of Venting Components
Equivalent Length of Venting Components
Component Feet Meters
90° Elbow 5 1.6
45° Elbow 3 1/2 1.1
2" x 4" Adapter 0 0
3" x 4" Adapter 0 0
Concentric Vent Kit 5 1.6
Polypropylene Flexible Pipe per Foot 2 5/8 0.8
6 - COMBUSTION AIR AND VENT PIPING










