Samiel wrote:
On Tue, 11 Jan 2005 08:44:49 -0700, "Charles Spitzer"
wrote:

if it's got an exterior vent, and the house is particularly airtight, could
there be some sort of harmonic air pressure fluctuations going on? that
would force the water in the traps up and down.

I'm not sure that it could be something that odd. It just seems like
air is coming out of the drain continuously as the heater runs. Could
the heater and a drain use a common vent?

Electric heat (which you say you have in another post) doesn't have any vents.

Damn, you gotta a weird one here, that's for sure.