Why Does My Downstairs Fireplace Fill With Smoke When I Burn The Upper Fireplace?
(Or The Other Way Around)
Why Do I Get An Oil Exhaust Smell From My Fireplace?
This is a common problem when you have two or more flues in the same chimney. When the flues are side by side, you can get a crossover from one to the other. Picture your house as a closed box. You have two outlets to the outside; your fireplace and your burner chimney, or two fireplace chimneys. When one is working, such as your burner or a lit fireplace, air is being drawn through the house and pushed up and out of the chimney. The air is being replaced through the unused opening, the other fireplace. Since the exhaust for the working chimney is right next to the unused chimney, a loop is created, sucking the air back in along with fumes and smoke (and carbon monoxide!). Sometimes, creating an alternate air source for the working unit will remedy this problem. Installing an Air Supply Ventilator can supply this air. Sometimes, raising one flue above the other will solve the problem. A FlueStretcher is an easy way of doing this. And sometimes, you need to do both, depending on how tight your house is. Sometimes, installing a Top Mounted Damper on the fireplace not being used will close it tight enough to prevent the loop effect. This is assuming there are no cracks or gaps in the liners to allow suction through the chase (the air space surrounding the flue inside the chimney itself).
