Harman P61 Overheat

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Oct 13, 2015
Hey folks! Stove is doing some funky stuff. The other night the stove on 'Stove Temp' setting started feeding way too many pellets for no reason. Stove was burning on low for quite some time, then all the sudden started over-feeding with the thermostat at the lowest setting. Same thing happened a week ago starting up the stove. Pulled the power to 'reset', and it seemed to fix the issue, until the fire died out inexplicably (feed rate 3 / stove temp / thermostat on lowest). I have seen six blinks come from the status light (pellets seems to be combusting just fine), as well as four blinks, but only when I unplug and plug in the stove when warm, and it only happens once with dial on 'stove temp' not 'room temp' - peculiar and contradicts user manual diagnostics. Stove has been recently cleaned including polishing up the ESP.

I'm wondering if the ESP all the sudden has gone bad. Do they last? If I were to attempt a resistance test, where do I touch the multi-meter test leads to? Not much an electrical guy, but sort of.

Or maybe the board is f'ed. Just looking for hints and tips.

I don't trust these stoves that's for sure. This thing is old, but we are good about maintenance, cleaning, and replacing parts and lubricating every year.

Help appreciated!
Last edited:


Feeling the Heat
Aug 17, 2007
Constableville, NY
ESPs seem to have a finite lifespan although some last well beyond 10 years. Not sure if there's an actually a rhyme or reason to a specific stove's ESP. I unplug them where they plug in at the board. I find them a PITA to get my Fluke probes to make contact with the female outlet I realize I need to make up an adapter to plug the probe into that's easier to attach my meter's probes to.




Minister of Fire
Nov 5, 2011
Kananaskis,Alberta, Canada
I would pull the probe and hit it a good wipe down with alcohol and check the wires to the board and make sure it’s clear of crud under the burnpot


Minister of Fire
Nov 5, 2010
Attica,,New York
Search the forum, there have been specs listed for resistance, ESP..


Minister of Fire
Nov 5, 2011
Kananaskis,Alberta, Canada
Another thing I’ve learned this year...if you’re using an APC or surge protector, try another one or direct to a plug outlet as either can be faulty and cause problems