Gas Furnace exhausts water?

Old 12-27-00, 05:36 AM
Visiting Guest
Posts: n/a

My natural gas fired furnace exhaust vent/pipe (PVC) was gurgling. I drilled a 1/4" hole in the bottom of it and a 1/2 gallon of water poured out! Since then, whenever the furnace is on, water drips from the hole. Is water used or produced by the combustion process? If so, what do I do?
(other than add a 'water feature' to my basement when I finish it!)
Thx. Steve
Old 12-27-00, 05:42 PM
Sharp Advice's Avatar
Admin Emeritus
Join Date: Feb 1998
Location: The Shake and Bake State USA
Posts: 9,927
Upvotes: 0
Received 7 Upvotes on 6 Posts


Your mention of a PVC vent pipe suggests to me your furnace is the ultra high efficiency model. Therefore, it's possible to accumulate moisture in the vent pipe.

Your correct. Part of the combustion process produces water vapor. This is normal. Natural gas is no exception. However, the amount you found in the pipe could be an accumulation over a long period of time and may not be from this season's useage only.

It's also possible the pipe is plugged somewhere's down stream from where you drilled the hole. could also be condensation is accumulating in the line after the furnace shuts down, since it's in a cold basement.

You didn't mention how long the furnace has been installed. If it's still under warranty or recently installed, contact the installers and ask them if a drainline was suppose to be installed on that model do to it's basement location.

If the unit is more then 5 years old, contact the manufacturer and inquire about that model needing a condensation drainline. Might also be a good idea to have a service dealer inspect the unit.
Old 12-27-00, 07:44 PM
Visiting Guest
Posts: n/a

Thanks Tom!
I'll try contacting the manufacturer for info on retrofitting it with a condensation drainline. It is a high efficiency model (about 2 1/2yrs old).
Thanks again, Steve.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: