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Megan
Fireplace Pipe Dripping
Megan

We had a direct vent fireplace installed and they ran the pipe up through the larger existing pipe that was there for the wood burning fireplace. The problem is the larger pipe keeps dripping. We have enclosed the space with dry wall but I can hear it drip and if I remove the thermostat box I can see small puddles of water. The company has been out 3 times to seal various thing on the pipe extending out the roof and place larger collars but it is still dripping. Is there a chance there is enough condensation building up to cause that much water? It is dripping today but there is no snow on the roof. I am at my wits end! Any feedback would be greatly appreciated

Sombreuil_mongrel
Re: Fireplace Pipe Dripping
Sombreuil_mongrel

The water vapor in the pipe is cooling and condensing. You either install insulated pipe or shorten the run to the outside. An inline booster fan would help, but IDK if you can legally do that.
Casey

Megan
Re: Fireplace Pipe Dripping
Megan

I don't think we can do the booster fan and considering the pipe is well attached is there a way to just insulate the pipe itself or would we be looking at an entire new section of insulated pipe? I know very little about these things but I am capable enough and know where Home Depot is. Thanks again for your reply!

Sombreuil_mongrel
Re: Fireplace Pipe Dripping
Sombreuil_mongrel

I don't know but "condensing" (high efficiency) water heaters and furnaces vent outside through a horizontal pipe made out of PVC (like plumbing) so they also may drain out the water and cannot rust. The exhaust temp is very low, because of the high efficiency; the warmth stays inside where it's needed. For that reason the air cannot carry very much water vapor, and there is not enough leftover heat to warm up a long section of vertical piping warmer than the dewpoint where vapor naturally condenses back into liquid.

Megan
Re: Fireplace Pipe Dripping
Megan

After reading the advice my husband and I went and bought some insulation and wrapped the larger pipe in the attic. It seemed to work but as I sit here typing this I can still here dripping. We did not run the fireplace yesterday or this morning. The current temperature is 25 degrees with 78% humidity outside. So either the insulation is not preventing the condensation or...? I am at a loss!

dj1
Re: Fireplace Pipe Dripping
dj1

Can you load up pictures of the vent on the roof? You can load your pics on photobucket and then post the link here.
We would like to see the flashing on the old chimney.

Is it raining when you hear the dripping water?

Megan
Re: Fireplace Pipe Dripping
Megan

http://s1156.photobucket.com/user/mtallon4/library/Fireplace

Above is the URL for pictures. It rained heavily last week and there was no dripping. There has been no snow accumulation on the roof for a week either.

Megan
Re: Fireplace Pipe Dripping
Megan
dj1
Re: Fireplace Pipe Dripping
dj1

Your roof top picture doesn't give a bird's eye view, but I would guess that this arrangement up there is leaking.
Get some roofers to go up on the roof, inspect it and offer their opinions. See if one of them can re-tar, or replace it.

Important question: where does the flex vent stop and the rigid vent start? How are the two put together? You could have warm air escape at this junction causing condensation.

I once had a phantom leak that lasted 2 years - it would leak and not leak, at the same time!?!?. Drove me nuts. It turned out to be a pin hole leak from the water heater vent flashing. I used silicone, not tar, to seal it. In my city tar dries up and cracks in 1 or 2 summers.

Benjamin
Re: Fireplace Pipe Dripping
Benjamin
Molly4 wrote:

After reading the advice my husband and I went and bought some insulation and wrapped the larger pipe in the attic. It seemed to work but as I sit here typing this I can still here dripping. We did not run the fireplace yesterday or this morning. The current temperature is 25 degrees with 78% humidity outside. So either the insulation is not preventing the condensation or...? I am at a loss!

You cannot wrap insulation around a chimney pipe is is a fire hazard

Megan
Re: Fireplace Pipe Dripping
Megan

The pipe the insulation is wrapped around does not get any heat from the flex pipe from the fireplace. There is a good 3 inches of clearance so I doubt it is a fire hazard.
If you are asking about the flex pipe it runs up through the middle of the old rigid pipe. I am not sure what you mean by the flex vent. It seems that when the temperature gets in the 20's is when the dripping happens. Snow or rain on the roof does not make it drip. So there has to be a condensation issue somewhere along the line. No idea how to figure out where.
And the idea that it might take 2 years to resolve makes me want to move!

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