I have a MF 3800. I live in the deep south and use it to supplement my electric heat. I also have a fireplace with a heat exchanger I made. The house is about 3500 sq ft but it has many ceiling heights ranging from 9' to 20'. The room it is in is my formal den/study, which is about 16x12 with a cathedral ceiling up to about 15'. I use a ceiling fan and a pedestal fan to move the heat out. I bought the mf 3800 off of ebay a little over a year ago as a "factory reconditioned model". It looked and functioned as new and I had no problems with it last winter. I used the range/level settings mostly, instead of the thermostat on/off setting. I mounted the thermostat on the back top with the bracket instead of remotely. Last year i could run the temp up to the low 90s in the room per the thermostat where the mf 3800 is located. This would normally require a setting of 4-4 to 4-6. If I didn't cut it down when the temp got this hot it would typically go into overheat auger mode and I would have to let it cool - but this was no problem as I figured out how to use it and this much heat would allow me to disperse good heat into the rest of the house. And as far as outside temps, I'm talking about temps from the mid 20s to say 35. However, this year I've not been able to use it as effectively. When I try to run the heat this high, the fire pot usually will get full and overflow. I can usually only run up to a temp of about 80 to 82 without overfilling the firepot and having the associated issue. I can get it a bit hotter but only right after Ive cleaned the pot. Formerly I could run it up to the low 90s even if it had run uncleaned for say 48 hours. I live in an area where these type heaters are uncommon and few people know much about them so was wondering if anyone had any thoughts? It still lights and runs fine as long as I keep the settings lower. I usually clean the fire pot with a wire brush and when carbon builds up I'll chip it off. I've taken the sides and top inside panels off regularly and cleaned the outsides of the heat exchanger tubes. I've used several different brands of pellets.