HARMAN advance? , what makes a stove go through pellets faster than years before, circuit board or exhaust probe??? I know a full hopper same pellets would heat properly and last about 24 hours on current settings from 2 years prior usage, I changed the potentiometer for feed, no change, so should I conclude board is bad or exhaust probe ??? all clean no blink's everything else seems normal.. another question. anyone know way to stop squealing grinding noise of auger, pulled and cleaned auger and tube before. Normal buildup? thanks Doug