Hi everyone- I'm trying to find out what is wrong with my stove. It seems to work ok on heat settings 1,2, and 3 for the most part. However, when I put it on #4, it runs for awhile and then the high fan will shut off, then start up again. It goes back and forth like this. So far I have: taken the inside plates off and seen no ash buildup, poked a hanger into the air flow hole inside the stove, blown through the air hose, cleaned the firepot and replaced the door gasket, checked my pipe leading outside. I also replaced the combustion blower last year. Other symptoms which may or may not be related: black buildup on the glass, esp. on the side that opens and buildup of pellets in the firepot on higher settings. Any help figuring this out would be greatly appreciated. My house heats best fully when the stove is on #3 or 4, so shutting off on 3 is not a good thing. Thanks in advance! Oh btw- the #2 light is flashing when it shuts down and it seems to go off and on for awhile on 4, with the high fan going off and on, but eventually it just shuts down with the #2 light blinking.