Took me 3 visits to figure out a draft problem that turned out to be the flue cap
Had a customer over in Davenport call me back three times about smoke rolling into the living room every time she lit the fireplace. I checked the damper, ran the brush, even scoped the flue, and everything looked clean as a whistle. Turned out the old flue cap up top had rusted and shifted just enough to block the draft when the wind came from the north. Two hours of poking around inside the house for something I could have spotted in five minutes from the roof. Any of you run into caps that only act up with certain wind directions?