Model #T9MPD100J20C1
My furnace will make a buzzing noise for about 3 minutes and then give me an error code of 3 flashes indicating a pressure switch issue. I found that if I take off the top front panel (not the one with the kill switch) and then manually turn the switch off then back on. The furnace will work for a hours and sometimes a few days, but eventually will have the same problem again. I have already changed out a new pressure switch and a new flame sensor. Please help...