# Gas furnace exhaust vent question



## nowell (Mar 13, 2005)

Our 5-yr old home has a Heil high-eff gas furnace installed in our basement. The exhaust vent duct (3" PVC pipe) runs about 35' across under the floor joists and exits the foundation wall. There is a considerable amount of condensation that drops from this vent pipe. Now that we have a finished basement, this condensation keeps our new suspended ceiling tiles wet & stained. I don't know why the furnace was not vented going up through the house to the roof top like our gas water heater that is right beside the furnace. Any suggestions? Would replacing the plastic 3" vent with metal dual walled pipe better insulate & eliminate the condensation? Can the furnace be vented to the water heater exhaust? Thanks.


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## rabadger (Feb 24, 2005)

No, the furnace must be vented on it's own. At closing you should have recieved all the paperwork that came with the furnace. Part of the paperwork is called the installation instructions. In the instaructions is a chapter dedicated to Venting. Their are restrictions to what you can do. If you do not have the instructions get the model number and serial number and call technical assistance at the factory. 

Look at the large copper line that runs from the A/C indoor section and outdoor section. The black product the pipe is in keeps it from sweating. That might work. Check with the factory first.

Richard


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## FWV (Jan 26, 2011)

*Gas Heater Vent*

I am wondering why a gas furnance vent has condensation in it and how to fix it?


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## hvactech126 (Nov 11, 2010)

> I am wondering why a gas furnance vent has condensation in it and how to fix it?


what efficiency furnace do you have? Metal or PVC flues? ALL GAS FIRED APPLIANCES have water vapor in the flue gasses. If the furnace utilizes a metal flue and you getting condensation, then it may be oversized for the connected appliances.

If your furnace uses PVC flues then it is designed to have condensation in the exhaust pipe.


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## kenmac (Feb 26, 2009)

the PVC shouldn't be leaking. the joints are possibly bad and need to be re glued


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## Jackofall1 (Dec 5, 2010)

kenmac said:


> the PVC shouldn't be leaking. the joints are possibly bad and need to be re glued


You got that one right on the nail head, my guess there is a coupleing not even glued. Glue the joints and there you go, fixed.


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## hvactech126 (Nov 11, 2010)

kenmac said:


> the PVC shouldn't be leaking. the joints are possibly bad and need to be re glued


don't know if you noticed that the question I answered was the post from today, the other post you were referring to was from 2005


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## bulls847 (Jan 30, 2012)

*heat from furanceexhaust*

.....


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