White Powder on Furnace Exhaust After New Roof

[Jim Katen]

Originally posted by Chad Fabry

It isn't in any code and, as far as I know, single wall pipe doesn't come with any instructions. It just seems obvious to me. If you do it with the male on the bottom, the joint will leak....

...harmlessly to the outside of the flue and not drip into the furnace?

That's always been the logic I applied.

The funny thing is, the longer it stays in the vent, the greater the chance that it'll evaporate into the steadily warming exhaust and not drip anywhere.

If you're getting enough to cause harm by dripping into the furnace, there's a bigger problem.

- Jim Katen, Oregon

[charlieb]

Originally posted by Jim Katen

Oh, and carbon monoxide alarms are cheap. Get some and install them.

Good ones are not cheap. "CO Experts model 1070" Replace every 2 years. The great pan maker Brian G. has shared this on several occasions.

[brianross]

An update: We now have heat.

Found a good HVAC guy and he confirmed that furnace exhaust blowing out the top of your hot water heat vent is not a good way to raise a healthy family. Long story short is that the furnace flue was not chock full of squirrels, birds or other foreign matter (we checked it from the bottom up and from the roof down). However, the roofers had installed a cosmetically nice vent cap which was preventing the flue to draft.

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For now there is no vent cap and plenty of good draft. My HVAC guy noted that over half of my neighbors have the same vent cap (same roofing company replaced most of the roofs after a May storm) and wondered aloud if most people would even notice anything like I did. Thoughts on this? I could see this being somewhat common - most roofing crews aren't considering proper venting while they are slapping down the hot tar up there.

Roofer actually called back and said he would be right over. Must have gotten in an accident or something because he never made it. I hope he is OK! I still need to rule out a leak at the storm collar and will keep on the roofer (not to mention I would like to cap the flue before I actually have birds in there), but I think my main intention for this post is resolved so I probably will not update further unless there is interest.

Again, thanks to all on this site. I found it fun and informative to interact with you guys.

B

[msteger]

Thanks for sharing your story with us and keeping us updated. Its always fun watching contractors from one discipline screw up a system of another discipline.

[hausdok]

Hi,

Perhaps a letter to the manufacturer of the pretty vent bonnet would be a good idea. They should know about this sort of thing before it kills someone.

OT - OF!!!

M.

[bd]

Originally posted by brianross

An update: We now have heat.

Found a good HVAC guy and he confirmed that furnace exhaust blowing out the top of your hot water heat vent is not a good way to raise a healthy family. Long story short is that the furnace flue was not chock full of squirrels, birds or other foreign matter (we checked it from the bottom up and from the roof down). However, the roofers had installed a cosmetically nice vent cap which was preventing the flue to draft.

Image Insert:

44.86 KB

For now there is no vent cap and plenty of good draft. My HVAC guy noted that over half of my neighbors have the same vent cap (same roofing company replaced most of the roofs after a May storm) and wondered aloud if most people would even notice anything like I did. Thoughts on this? I could see this being somewhat common - most roofing crews aren't considering proper venting while they are slapping down the hot tar up there.

Roofer actually called back and said he would be right over. Must have gotten in an accident or something because he never made it. I hope he is OK! I still need to rule out a leak at the storm collar and will keep on the roofer (not to mention I would like to cap the flue before I actually have birds in there), but I think my main intention for this post is resolved so I probably will not update further unless there is interest.

Again, thanks to all on this site. I found it fun and informative to interact with you guys.

B

Brian,

What is the name of the good HVAC contractor you found?

I also live in Maple Grove and have the same white powder problem.

However, the problem may be the flue top cap and the routing of the flue through the attic.

Thanks.