On Wed, 10 Aug 2011 09:05:28 -0700 (PDT), Mikepier
wrote:



The water heater is vented through an exterior brick chimney. The
attic fan is on the opposite side of the house.


You just put that water heater in, right?
Think you posted pictures and we were talking here about vent
placement.
Did the old heater have 4" vent pipe?
How many inches did you stick in the chimney?
Did you put in under the furnace vent instead of side by side or
under?
I think I said my 4" water heater vent was a few inches directly over
the 8" furnace vent. I checked just now and that's how it is.
Don't know if this means anything, but something to consider since as
I recall you changed the setup.

--Vic