Dripping sound in ductwork

[r2828]

My furnace is up in the attic. Whenever the furnace is going to come on there is a loud dripping sound that echos in my kitchen, bathroom and bedroom for about 10 seconds before the heat comes on. We checked upstairs and there's no water dripping anywhere and can't figure out where the dripping noise is coming from. We asked a heating guy and he said that it might be the ductwork going from cold to hot. Anyone have any ideas as to what it might be or how to resolve this problem. It's driving me crazy.

[Ed Imeduc]

Where you are and how cold helps. Also what kind of furnace .Gas can the drip come from the flue pipe.Any metal duct work there in the attic on the furnace not insulated ???? Check them out and come on back in the same post . Some one here might be able to help.

ED ;)

[Jay11J]

It maybe the duct or the heat exchanger cracking from the heat/cold expansion.. Sometimes there is nothing can be done about it..

They say on older system, that you remove the fan from the control, and heat the exchanger pretty hot to "break in" the metal.