Distribution Blower on HARMON P61A

First time posting. I have had this Harmon P61a pellet stove for the past 9 - 10 years now. Works great. Until a few days ago, when I discovered that the Distribution Blower will only blow on high, even though it is set on low. After a while in will reduce to low, then back up again, mainly staying on high. I use the Room Temp. mode and a feed rate of 2, which has ALWAYS worked for me in this setting since I started to using the stove. Same pellets as well. I get 3 blinks on the Status light. So, after reading through past forums on this site, I did a through cleaning of the stove today. I found that the ESP probe was covered in ash and made sure that it was cleaned and now everything that can be cleaned and vacuumed had been done, including the two motors at the rear of the stove that had a collection of dust and crap on the fins etc. Stove pipe was cleaned as well. Over the past 10 years or so, I clean all the stove, 2 or more times a season, as I burn 195 bags (50lbs. each) per season. Has anyone had experience with this problem with the Distribution Blower? I read an old posting by a gentleman with this problem but I could not find anyone's reply to it. Thanks

I just checked the stove and it was blowing on low speed, so I turned the dial (Room Temp) to high and the blower went into the high mode. But then I turned it back to low and it is staying on high.....

bags said:

Where is your igniter switch set. Auto or manual?

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Auto. Always has been on auto since day one.

bags said:

If you are running Auto igniter, room temp, and set the temp dial to desired temp then your stove will run itself and control blower fan speed.

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It always has work the way you just described, until the past couple of days. Now even after a through cleaning, the fan, set on low speed, goes to high on its own, back to low, times go by, back to high etc.

Lake Girl said:

Just an aside, you cleaned the fins on the blowers but did you blow out by the motor windings?

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Yes. Both were cleaned.

bags said:

Something I just learned not long ago. I turned my stove off to do it and unplugged it. Your pot switches which Bioburner is citing above might be getting old and worn. One thing to do is rotate all of your dials (room mode / stove or constant mode dial is one) fully several times. All the way up and all the way down. Do this with all three dials because it has been said here that this will somewhat refresh the contact they make and possibly "fix" the problem. This is a quick and easy "fix" possibly free of charge. Worth a try. Did you take out the ESP probe and clean it? Has it ever been replaced?

Search threads on Harman pot (potentiometer) switches and control boards not working right. Bio will be much more help on this than me. These quality ( lol! ) switches are $5each or I think $10 for the three but that requires you soldering and messing with the control board. There is also a place on Ebay ( maybe) that fixes them and tests your board for $40. Do not hold me to this. I am just tossing out things for you to look into to see if it fits your issues.

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Thanks for the input. I have ordered the kit of three potentiometers from Ebay and will install them in a week or so. I believe this should cure the inconsistency of my distribution blower speed. I will let you know how I make out with it.

bags said:

Good Luck! I haven't done those yet myself so any questions there direct to Bio's way. He is familiar with them. I am interested in how it turns out so do let us know.

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I will do so.