Harman P35i distribution motor not turning on. Bad potentiometer? Any way to test?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

Kuato

New Member
Oct 31, 2020
1
Oregon
Hello all!

My Harman P35i pellet stove insert distribution motor is not working. I've mined the threads and tried just about everything. I'm now thinking its the Mode Selector potentiometer and wanted to see if anyone had some insight. Here is whats going on.

Distribution motor wont turn on during room temp mode
Distribution motor will turn on in test mode and in power down mode.
Spinning the room temp knob seems to trigger board (as in if I turn it to lowest temp the stove slows burn down, higher temp it starts cooking again)
Feed knob also seems to work as I can put it in test. (also changing feed from 3-6 you can hear the increase)
Mode Selector knob I think is the culprit. I can swing it to off but no other setting seems to change stove behavior

Here's what I've tried:

Cleaned stove completely and ESP probe. (after that I had one burn where the distribution motor came on but very faint)
Checked room sensor wire and moved in room slightly.

I'm thinking then its the room temp knob...the stove is not reading the setting so it doesn't turn on the distribution motor to blow in to room?
If this is the case whats my best course of action, order knobs and find an electronic repair shop to solder? Send to Control board to Harman for repair?

Any other ideas?

Thank you in advance,

(last thing to consider... I'm going through my last bit of fuel from last season (Douglas Fir pellets). A lot of crumbles and some moisture not much. Fire still gets going pretty good and stove is hot to the touch but I thought maybe ESP is still not getting hot enough?)
 

gfreek

Minister of Fire
Nov 5, 2010
1,421
Attica,,New York
Harman will not repair the board..Could be bad ESP ? I keep an extra..Maybe, unplug it & clean the potentiometers with electrical contact cleaner. They can be replaced , with the correct ones. I know the variable ones can, not sure about the mode switch. Hopefully someone will respond with more ideas.