Smoke Leaking Around Damper Rod Hole

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New Member
Jul 18, 2023
SW Iowa
Built in fireplace when the home was built in 1982. Corner type with the flue pipe going straight up and through the roof. 2 fresh air intakes from outside air are installed. Problem is when the blower is turned on above low speed we get a smoke odor into the room. I have had the fireplace apart for access to the damper area and found both holes for the damper rod through the flue pipe were greatly enlarged. Could not get at the back hole from the fireplace so would have to remove part of the false wall front over the fireplace for access. With a mirror and could see the enlarged hole. The blower fan draws air in at floor level and circulates it up and around the firebox and blows it out the top front of the fireplace. My question is how is the best way to fix this enlarged hole. One idea is to use a piece of sheet metal, drill the proper size hole, places fireproof insulation over the old hole and clamp the "patch" in place for proper operation of the flapper. Then do the same with the front. I did a temporary fix to the front end of the rod with furnace cement, oiling the rod first so the cement would npot stick to the rod. It help a lot but did not stop it. I am sure the smoke is being drawn from these two enlarged and open type hole that lead directly into the flue. Is my repair idea sound or someone have a better plan of attack? Any and all suggestions are appreciated.
Since the chimney should be pulling hard when a fire is lit, air should be pulled in those holes, not escaping. If the smoke is coming out those holes, I'd look at draft first. Common issues are flue diameter, chimney height, blockages in the flue or cap, quality of wood being burnt, and this time of year, the temperature difference between inside and outside isn't great enough.
The fan is not turned on until the firebox has had time to heat up good. This unit was installed according to manufacture specs at the time it was installed in 1982. Chimney size has not been changed. I have tried raising the flue another 5' as a trial and did not solve the issue. Never has been any blockage in the flue and it has been cleaned every year that I have owned it. Wood is seasoned dry oak , hickory, some ash and walnut. This issue just showed up about 3 years ago. Never bothered before. The common issues you mentioned have been covered and none of them is related to the air that is moved from the floor, around the fire box and back out into the room. The holes in the flue need to be taken care of so the damper will work right any way. Those holes are the only opening I can find where smoke can get mixed with the air the blower is moving. Thank you for the suggestions. Every little bit of information helps.