keeps coming on and the Easyfire brand (Sierra products, formerly Empire ) pellet stove shuts off after a couple hours of operation. This model has to warning lights, one for high temp and one for blocked flue, the high temp light is the one that keeps coming on. I cleaned the stove and the stove pipes and chimney. But the problem persists. I replaced the high temp sensor last year (unrelated) There is a part of the flue thats between the fire chamber and the stove pipe, just after the combustion fan (this is where the temp sensor is located) that I cannot get to in order to clean. Anyone have any experience with something like this?