Hi, I have a Jotul 500 purchased new in 2000. This year it was sometimes burning pretty hot despite having the air intake turned all the way down. The gaskets are in pretty good order, so a friend installed a stove pipe damper about a week ago. Ever since then it's really difficult if not impossible to get a good hot fire going. It burns but it's as if the air intake is always halfway or more closed. Yes the damper is fully open. I want the thing out of the pipe but with sub-zero temps I can't let the stove cool off long enough to have it done. Is it likely to be the damper or is that a coincidence?