Harman Advance Circuit Board Problems

[timjk69]

I need help with my Harman Advance. While under warranty the circuit board was replaced due to a dead spot in the temperature control potentiometer. Seems to be a common problem on these stoves. Last fall started having the same problem again, but now out of warranty. Found the exact replacement POT on ebay, (3 to package) much more economical than a circuit board. Was simple enough to replace the faulty POT, but now the auger motor runs too slow to fill the burner up and ignite. Completely different symptom that I tried to correct.
Hoping someone out there has had a similar experience and could give me some ideas on were I went wrong.

Tim

 

[jtakeman]

I don't know much about the Harman stuff, But I would assume the pots would have different values.

 

[heat seeker]

To expand on j-takeman's note;

Measure the resistance of the old pot (two outer legs) and compare to the new. Probably different values.

 

[timjk69]

Thanks for the reply.
Actually the replacement pot is the same brand, part # and value.

 

[Delta-T]

check the fines box on the back of the stove. If its getting full it will limit the movement of the slide plate (in the feeder body) and limit the amount of pellets that can feed.

 

[Bkins]

Are you using the same pellets as before you replaced the pot? Are all the pots in the board the same. Wondering why they are sold in groups of 3. Maybe check the other pots to see if one bad one caused another to go bad. JAWAG.

 

[timjk69]

There are 3 pots on this unit, all the same # and value. I guess this is why 3 per package, also one at a time cost would be less less than S$H charges. One of them does regulate the amount of time the auger runs, ie so many seconds per minute cycle. I only replaced the one for the room temperature sensor, which was acting up.
I did clean out the auger slide box, I've never had more than about 1/8 per cup sawdust a couple times per season.
I guess should test the other 2 pots, one for pellet feed timing and one for distribution blower. I believe I need to remove them to isolate and get an accurate reading?

 

[heat seeker]

Removing would be best, no chance of backfeeding sensitive components on the board. Also, other components on the board may affect your readings.

I like to use an analog meter to test pots best, since you can watch the needle move smoothly as you turn the pot. A digital meter works fine, too.