In Canada construct all combustion air and vent pipes for this unit of CSA or ULC certified
3.Combustion air and vent piping connections on boiler are sized for 2" pipe. Any pipe size change (to 3") must be made outside of the boiler casing in a vertical run of pipe to allow for proper drainage of vent condensate. Due to potential for flue gas temperatures over 155°F, the first five (5) feet of vent pipe must be CPVC, the remaining vent pipe can be PVC. If any elbows are employed within the first 5 feet of vent, they must be CPVC too. Two (2) - 30" pieces of 2" CPVC pipe are furnished with the boiler.
NOTE: The transition from 2" pipe to 3" pipe must be made in a vertical run.
4.Combustion air and vent piping lengths,
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The first 5 feet of “TOTAL EQUIVALENT LENGTH” of vent piping run must be CPVC:
The length of pipe is counted from the boiler jacket (air intake pipe) or from vent tee (vent pipe).For additional elbows, reduce the maximum vent length as shown:
2" 90 degree elbow
Example: To add 2 additional 90 degree elbows to a 3" pipe for a 75 boiler. Each elbow is 3 additional feet per 90 degree elbow for a total of 6 feet. (1 elbow @ 3 feet + 1 elbow @ 3 feet = 6 additional feet of pipe) The total additional pipe is then subtracted from the maximum allowable pipe length to give the new maximum length of 94 feet with 6, 90 degree elbows. (“TOTAL EQUIVALENT LENGTH”: Original 100 feet max. - 6 feet for 2 additional elbows = new 94 feet maximum length).
5.Combustion air and vent piping to be pitched back to boiler at minimum ¼” per foot from intake and vent terminals so that all moisture in combustion air and vent piping drains to boiler. Pipes must be pitched continuously with no sags or low spots where moisture can accumulate and block the flow of air or flue gas. Combustion air and vent pipes must be airtight and watertight.
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