Looking for advice. I have a US Stove (King) 5500. Everything about the stove operates fine except that I can’t adjust the room fan. In automatic, it never changes speed, and manually changing the speed has no effect. I assume the fixed speed is high, probably level 9, because it is very loud. I’ve replaced the fan, replaced the control panel, and neither change had any effect. The loudness of the fan isn’t like a bearing issue, it seems like a normal fan noise set very high. Any suggestions?