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LP- 428 REV. 9.2.14
Figure 16 – Unbalanced Venting
NOTE: Exhaust vent must always be piped vertically in an unbalanced venting configuration.
Take extra precaution to adequately support the weight of vent pipes terminating through the roof. Failure to properly support roof
terminated vent piping could result in property damage, serious personal injury, or death due to flue gas leakage.
All vent pipes must be glued, properly supported, and the exhaust must be pitched a minimum of ¼” per foot back to the boiler to allow
drainage of condensate. Exhaust connection insertion depth should be a minimum of 2 ½” for 500 models and 3” for 850. When placing
support brackets on vent piping, the first bracket must be within 1’ of the appliance and the balance at 4’ intervals on the vent pipe.
Boiler venting must be readily accessible for visual inspection for the first three feet from the boiler.