Is this a late model efficient furnace? They have drainage systems for
condensation. Does yours have a condensate pump or is it high and have a
condensate drain? Maybe it is plugged and condensate is backing up though
usually if that happens the furnace shuts down. Hard to know what is going
on without seeing the instulation.


"Juping Jin" wrote in message
om...
I can hear water drops on wood (one drop in about a minute) in the dry
wall when furnace is working, and even in the first few minutes after
furnace stops. Last week, I had a person to perform furnace
maintenance and asked him this question. He said that was normal,
still, it causes my concern. The only thing I can think of is moisture
condense on some pipe and then drop down from pipe. Even that, I feel
it is not normal to have water drop down.

Your advice will be sincerely appreciated.

Thanks.

andrew.