Harman PF100 No Temperature Control


New Member
Dec 4, 2019
Hello, maybe you guys may be able to help with this. Here is what I have going on. The past few days I had the Harman PF100 pellet furnace going and it seemed to be running ok, but temp control did not seem to work with thermistor on wall or in service mode, it stayed steady at 72-73 degrees regardless of what it was set at. So I shut it down cleaned the inside and cleaned the ESP sensor. I cleaned the combustion blower and found a bunch of holes clogged of ash in the fire pot which are all fixed now and runs a lot better. I had it running all day today and ran pretty good with no errors. However I still do not seem to have any temperature control as the unit will bring the house to about 72-73 no matter what you set it on the wall or in service mode, the fire just stays consistently high but even. I did an experiment by changing it to service mode on the lowest setting of 1 on the units on unit temp adjustment for about 40 mins(probably a little more). Now the unit did get somewhat cooler, the fire was still pretty high. I imagine during this time, the fire should get pretty low by then. I don't think the problem is in the thermistors, to me it leads me to think the ESP sensor may be at fault with registering incorrect fire temperatures which make it hard for it to regulate at the correct temperature. I don't think the control board is at fault since all functions on it seem to run ok, just with temperature control off. Let me know if you guys have some insight. Thanks again guys.