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gdmorr
Odor coming through heating system.....
gdmorr

I have a multi-level home with a seperate heating/cooling unit for each level. Over the past month I've noticed an odor on the top level that smells like mild sewer gas. The bathroom on that level gets used and I've checked to see if the odor is coming from the traps there (it is not). Again, it has only started in the past month or so (since the heat has been turned on). I've looked in the ducts and the blower motor area and nothing smells or looks odd. Any suggestions on where to go from here? The other two levels (each with their own units) do not have any odor. I moved into the house in May of '08 and all through the summer I never noticed the odor.

Thanks!

ed21
Re: Odor coming through heating system.....
ed21

I would check to be sure the condensate drain is working. It may be clogged and water could be sitting in the condensate tray.

Blue RidgeParkway
Re: Odor coming through heating system.....
Blue RidgeParkway

Could be a compromise in the waste plumbing venting. These problems can show up when the weather cools outside. Could be a shared plumbing wall venting up noxious odors from a compromise from the one of the lower units.

gdmorr
Re: Odor coming through heating system.....
gdmorr

I appreciate the comments. I should look more into the vent system as I know the main floor washer was not vented properly (no trap in the line so during the warmer weather the noxious odors come into the laundry). I am now wondering if this could be part of the problem or an indication that I have other vent problems. Thanks...

ed21
Re: Odor coming through heating system.....
ed21

Could the condensate be plumbed directly into the vent or waste stack? If so, it shouldn't.
PS. Putting a trap on the washer drain shouldn't be all that difficult.

gdmorr
Re: Odor coming through heating system.....
gdmorr

I believe I have found the main problem based on your advice. The condensate drain is piped directly into a vent. I'm guessing that the noxious odor is being pulled up through there when the fan kicks on. Since it is in the attic on the third level, any suggestions on the best way to re-direct the condensate pipe?

ed21
Re: Odor coming through heating system.....
ed21

Not an hvac guy, so I don't know how the condensate drains are normally handled on a multi-story installation like yours.
Pretty sure draining to the vent isn't to code or advisable.
In any event if you can create a trap in the drain line and be sure to keep it filled with water you may be ok with the odors.
It will probably need to be done with all units.
Their may or should already be a trap, but it could have dried out. Try pouring some water into the condensate tray and see if that helps. In the summer the condensate from the a/c probably kept a trap filled up.

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