I bought a used Gibraltar CFI coal insert last March. Since it was so late in the season, I did not have sufficient time to get to know how to best use it before the weather got too warm. It still has been too warm here in Maryland to fire it up using coal, so I have been burning wood and trying to learn its quirks. I am looking for some general principles as to how to adjust the fire. Here are the mechanism my insert has to adjust the fire:
1. slots on the ash pan door that can slide from completely closed to completely opened. It is obvious the more you open them, the hotter the fire.
2. a mechanical damper right at the top of the firebox. This damper slides over the circular exhaust exit flue opening to adjust how large that opening will be. The front of the stove has a rod which can be pulled out (this opens the damper completely) or pushed in (this closes the damper so the flue is about 20% opened). It is obvious that as you pull this rod out, the fire livens up.
My question is how best to use these two adjustments, in combination, to get the most BTU in my house and less out the chimney? I am afraid that closing the mechanical damper too much might choke the fire and allow CO to get into my house (I have a CO detector and it has never moved from a reading of zero). But when I closee that damper, the temperature rises on my thermometer as the fire slows and my perception is that I am getting more BTU in my house than out the chimney. I could just keep the damper completely opened and use the adjustment on the ash pan slots to control the fire, but is that more efficient?
I must confess runing this thing is a lot of fun. When I burn wood, I feel like Ben Franklin. When I burn coal, I feel like some 19th century fireman stoking a B&O locomotive.
Regulating the Fire on My Gibraltar Insert
i too have a gibralter insert.. I burn wood when the temps arent to cold. when the temps get cold at night I load the box with anthricite, up to just below the fire brick. cut the damper almost closed and then open the ash door oping about 1/4 open.. last about 14 to 16 hrs when temps are 50 day 40 nights,