This morning I discovered the distribution blower on my Invincible had stopped spinning, but the stove was otherwise burning normally. After removing the side panel I turned the fan slightly with my fingers and it immediately started spinning at what seemed to be full speed. When I checked in on an hour later it had slowed to barely turning , and this time would not speed up. I don’t hear anything unusual from it - humming or buzzing. Has anyone else experienced this and does it mean it needs to be replaced, or could it maybe just need to be lubricated? If I need a new motor, can it be separated from the assembly or does the whole thing have to be replaced?