Induced Draft Vent Pipe Pitch

JerseyJK

I have a gas hot water heater with a power vent.  The vent pipe is PVC and runs out the wall.  It does not share a vent with any other appliance.  The first 4' of the vent pipe runs with a slight (about 1.5" over 4') negative pitch to get around an obstacle before it pitches back upward for another 4' or so to exit out the exterior wall.



My question is, with a power induced draft vent system, does the vent pipe need a positive pitch or is the initial downward pitch ok? 

John Mills_5

not good

down then up creates a trap that could fill with condensate water. Doesn't sound deep enough that it could fully fill and block but it isn't right.

JerseyJK

Thanks

Makes perfect sense.  Thanks for the response.

icesailor

PV Water heaters

All the power vented water heaters I've seen woupdn't condense if they had to. The exhaust was too hot.