Smoke from fireplace flue being drawn down flue for furnace
We have an 11"x11" flue for our fireplace and a 9"x9" flue for furnace (side by side). After installing chimney caps the smoke from the fireplace flue is being drawn down the furnace flue and into our basement. This smoke is being drawn upstairs and onto our first floor where the fireplace is. Did not have this problem before chimney caps were installed. If we open a window by fireplace the problem is solved but cold winter air comes in too. If we close the fireplace doors the problem is also solved. We have a 3" dia. air supply from louvers on the side of the chimney. We would like the doors open. How can this problem be addressed without removing chimney caps? The chimney is 2' above the ridge of the house.