Thread: Fireplace odor

I received a call today from a homeowner of a 25 year old townhouse. House has two masonry fireplaces (one on first floor one on second floor), fireplace has been used only once. Just within the past two weeks there is a fireplace strong odor. I asked if anything has changed and her response was the heating system. Old unit has been replaced with a 90% unit. At this time without going to the home, I have no idea if the flue which is being used by the water heater has been relined now that the heating unit has been removed. I'm thinking for some reason the pressure has changed in the home. Anybody have ideas?
Rich

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Richard,
My guess is that the old furnace was vented into a common flue which also served the fireplace. Since a new high efficiency furnace has been installed and may not use the flue, cold air being heavy is now falling down the cold chimney, thus the fireplace odour. But then again once you return you maybe able to provide us further info that would assist in a diagnoses.

Cheers,

Originally Posted by Richard Roshak

strong odor

Anybody have ideas?

Rich

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A used discarded pair of.....

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I agree that it's a negative pressure problem. New furance, different fan speed, more air moving through the ductwork, if there's a hole somewhere more air is now being pushed outside - result is more air being sucked down the chimney(s) into the house resulting in the 'fireplace smell'

It could also be that the new installers left a gap in the ductwork (assuming it's outside of the house in a garage or basement) and now there is a negative pressure. The first thing I'd do is look over the install very carfully and look for air leakage anywhere they distrubed things.

Many 90 plus furnaces Installers do not connect the supply opening directly to the outside.
I could imagine the makeup air being drawn from a chimney.
I would guess that the latent heat from the old furnace kept the flue dry and warm so as to maintain a draft..
But that makes no seance if it's B vent..