I have the englander pellet stove 25-pdvc for three years now and after is shortly heats up a loud high pitched harmonic squeal comes and goes. It is affected and temporally quieted by increasing the blower fan settings. Ive also removed the rear cover panel and place a 1ft square fan blowing on the fan motor which really seems to help the noise go away. Please help. Im at my wits end after tons of research and replacing the combustion fan motor. Although I did just order a new OEM Blower PU-4C442 as my last ditch guess. Hopefully its just the bearings in there and the new one when it arrives and installed will solve my issue.