Exhaust vent slope - sealed combustion boiler

Bob_Engelhardt

I'm installing a Weil McLain CGs boiler (sealed combustion).  The exhaust vent is supposed to slope back to the boiler where a condensate drain is the first horizontal fitting.



It would be REALLY convenient to slope the vent away from the boiler and have the drain just before the exterior wall.  Is there a good reason why I shouldn't do this?



Thanks,

Bob



BTW: the vent is vertical for 4' then horizontal for about 8'.

Henry

Certified I&O manual

You must follow the certified Installation & Operation manual that comes with the boiler. There are several good reasons for that. The manufacturer has tested and certified the venting. Not following the instructions could lead to loss of warranty, tagging by the OHJ, lawsuits etc...

Tim McElwain

Simple answer is

the condensate will freeze and eventually plug the exhaust.

Bob_Engelhardt

Thanks

"You must follow the certified Installation & Operation manual ..."  Yeah, I knew that ... just hoping for the answer that I wanted  



I'm still curious as to why it would pitch back, rather than away.  Away seems better - if the drain becomes clogged, "away" would overflow outside, where "back" would go into the boiler.  Also, wind-driven rain would not have to be handled by the drain.



Thanks,

Bob

Bob_Engelhardt

Wouldn't freeze because ...

the drain would be inside, just before the wall.

John Mills_5

It could

Cold air from outside will come in during the off cycle. If it is done, put the needed trap as low as possible from the vent and maybe the water in the trap won't freeze.