Smoke down dual flue

[Sawbeans]

We have a dual flue fireplace (one in basement one upstairs, separate flues but right next to each other). The basement has a pellet stove installed with a liner. We are getting some smoke coming from the pellet stove exiting through the top and coming down through the other flue (steel damper shut). We don’t use the fireplace but are about to sell our house and don’t want to spend a lot of money on a solution. We’ve read hit and miss reviews about balloons and don’t really want to spend the money on a top damper. Any other ideas?

 

[begreen]

Do the two flues terminate at the same height? Can you post a picture of the chimney top?

 

[Sawbeans]

Yes they terminate at the same level. This is the best picture I have readily available

 

[begreen]

Therein lies the problem. The exhaust from the pellet stove is under pressure. It is being forced into the other flue. The chimney also needs a proper top cap.

 

[Sawbeans]

Therein lies the problem. The exhaust from the pellet stove is under pressure. It is being forced into the other flue. The chimney also needs a proper top cap.

What is the proper top cap?

 

[begreen]

I should have said top plate. This example is for a single flue.