Thermo-siphoning?

[Deron]

Burning downstairs fireplace in a double flue causes odor problems upstairs.

In a double setup like this, wouldn't thermosiphoning have to occur at the top exhaust of the clay liners? I covered up the upstairs liner
with rubber roofing and I still get the smell. Wouldn't this remove thermosiphoning as a suspect?

This is the first time I've been up on the roof...would the cracks in the crown cause the heavy smell of smoke with no smoke?

 

[begreen]

Looks like a possible starting point. In the test, how was the upper flue covered? Was the cap removed and the rubber cover weighted down with a brick or something? If yes, I agree that I would have expected that to seal of the source of the problem. You might want to ping Craig about this one. It's an area he worked on remedying with the Extendaflue product.

 

[Deron]

Cut a piece to fit over the opening, then wrapped duct tape around tightly and used wire
to seal the deal. It's a very thick rubber roofing product so there's no way any smoke could
have penetrated.

The cracks in the crown? Wondering if it's seeping over under the crown?

If not, then it's got to be seeping thru some deteriorating mortar joints in the stone.

 

[begreen]

That should have worked pretty well. If this is happening in the brick chimney cavity it could mean a cracked tile is leaking. Worth checking for this.

 

[Deron]

That should have worked pretty well. If this is happening in the brick chimney cavity it could mean a cracked tile is leaking. Worth checking for this.

I think you're right, that or a bad mortar joint/shoddy masonry work.

The deal is we smell it bit can't see the smoke upstairs. That being the case, would a SS liner eliminate the odor?

Got an estimate of $2300 to install a liner which I thought was a little high, but on the other hand I do have a 3 foot offset
so it won't be a picnic.

But dropping $2300 on a liner install and still having an odor problem would be devastating.