For 2+ months I was able to heat most of my 3,000+sf home on nut coal with my harmon magna-fire elite insert, and smile with glee as the propane truck passed my house.
Then, out of the blue she stopped working well. I had virtually no draft. Came to discover that low barametric pressure, humidity and wind direction was an issue.
I have a very large 30+ ft class A unlined chimney, that needed just the right enviornment to preform effectivley.
Just had an insulated stainless steel liner installed, along with a small terra cotta extension to the flue ( have three flues at the same height above the roof that were competing for draft ) and the harmon was humming last night with outside wind gusts up to 60mph.
Can now laugh at the propane truck again.