2014 Harman P43 Auto Ignite Troubleshooting

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New Member
Sep 14, 2022
Owls Head, NY
I bought and installed this used stove last season. Ran all season like a champ. I cleaned it as needed but never disassembled it and did a deep cleaning until now. We have used it a dozen times or more this fall without so much as a hiccup.

A couple of nights back my wife was pouring a pellet bag in that was from where our 120 lb dog had been using a low stack of bags as bedding this summer. The bags had been worn thin and ripped here and there by our big boi, so as she poured it in the sack tore in the middle and a lot of pellets spilled across and in-between the stove. She cleaned stuff up and did her best to check things before turning the stove on. She says about 8-10 minutes later while the stove was making its usual buildup noises there was a sudden FWOOMP and the stove stopped making fan noises. From there nothing she could do would get it going again.

I got home late and wasn't able to look at it until the following day. I'm not super mechanically or technically inclined, but I use plenty of the Hearth forums and youtube to get by. Here's what I've seen, done, and where I'm at. I would love some help if folks have any to suggest.

1.) Broke down any build up and soot inside the stove, vac'd it out
2.) Cleaned off the heat exchanger
3.) Scraped/opened up and cleaned out the burn pot
4.) Put an allen through the burn holes, removed & cleaned the flame guide and brick
5.) Cleaned out combustion blower paddle, flue, and ESP
6.) Paddle was not moving freely, removed and cleaned
7.) Checked the combustion blower motor & found its fins broken and stuck by pellets that had gotten inside it
8.) Replaced the combustion blower motor (green to ground, black to red, white to white)
9.) Opened up the feeder box and cleaned out the fines and pellets
10.) Pulled the auger out to clear any jams and cleaned in there
11.) Took the exhaust vent off and cleaned it all out, then resealed it
12.) Disconnected the cold air intake on both the thimble and the stove then resealed
13.) Checked the tubing to the differential switch, seems connected
14.) Removed the seal to the stove door and resealed with a 3/8" Rutland graphite rope
15.) Checked ash pan door seal (seems just fine, but could replace it)

So now, when I put it in test mode, the distribution blower, combustion blower, and feed motor lights come on. Everything sounds right, but the auger does not turn and feed pellets. After 30-60 seconds the feed motor light goes off and the other two stay on. I can hear the fans blowing. No codes blink. Flipped the auto/manual switch a few times. I'm stumped. Do I buy a new auger motor and try that? Differential switch? I'm willing to do both. I'm just frustrated by not getting anywhere yet and not being mechanically minded enough to where I can problem solve beyond what I look up on here, reddit, or youtube. I don't know how to gauge the success or failure of my efforts. Any thoughts? I suppose I could always suck it up, admit defeat, and call a tech. We have a great dealer a town over.
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With the stove unplugged can you turn the auger by hand? You can also straight wire the auger by disconnecting it and using a cut off lamp wire or something similar and wire it to the auger wiring to see if it will turn.
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Once I'm back home I'll check. On my first run through the stove I couldn't move the auger by hand, which is why I pulled it all the way out to clear it. I'll try connecting it directly too. Thanks!
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Believe the pressure switch is in the circuit for both the feed motor and the igniter. Hopper closed, fines cover on tight ? I had issues once when I didn’t seat fines cover properly.

2014 Harman P43 Auto Ignite Troubleshooting
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So while I was in town I picked up an auger motor just in case (returnable if unopened). I came back and used a lamp cord to make a connection to direct power. I tested it first on a thing I know I replaced and is working, the combustion blower, and that powered on. I plugged it into the auger motor and there is a buzz and some warmth on the motor but now movement. So I'm guessing that means open the box and replace it.

And thank you so much for that diagram above, @doneill127. Yeah, the pressure switch is the thing I "understand", but don't really know how to solve for other that checking that the intake and vents are clear and open--plus sealed tight. I did remove the tube off of the pressure switch, blow it out (little bits of pellet dust maybe), and then reattached it to the switch and the vent connection.

I'll report back after that auger motor is on.
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I should also add, that the hopper is closed and the fines box I did not seat properly the first time I cleaned it out, but I believe I caught that quickly and secured it properly before getting to this stage
All right, I got the auger motor on and reattached everything. I put it into test mode and everything came on. Distribution and combustion blowers and then the auger started feeding--BUT--I must have done something wrong in reassembly. The diagram is below, but this what's happening:

1.) Auger spins
2.) Feeder cam bearing spins with it
3.) Feeder cam bearing enters the feeder pusher arm
4.) Feeder pusher arm begins to move
5.) Feeder cam bearing comes off its circuit inside the feeder pusher arm in the middle of its circuit
6.) Feeder cam bearing reconnects with the end of the feeder pusher arm
7.) Feeder cam bearing and feeder pusher arm seize up together for a moment
8.) There is a pop as the two separate pretty hard

My guess is this: I foolishly tested the new auger motor before mounting it which put it out of its starting alignment. I noticed this early on and recalibrated it by watching it turn and then unplugging it when it got into place--I gauged it against where the previous motor left off. My first impulse is to dismount the new motor, try to recalibrate it again, remount, and see what happens. Feeling hopeful--as well as like I'm my own worst enemy. My other enemy is my big hands and the auger motor mounting screws attaching on the back of the mounting arm.
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I just got the auger motor to run through the feeder arm without hesitation, stoppage, or any true exertion. My calibration idea was hogwash, apparently. Turns out the resistance was a result of my slider plate (2.12) being disconnected from the paddle on my pusher arm (2.9). So the arm was out of alignment by virtue of not connecting with the slider plate, and the inaction of the slider plate was keeping it from feeding pellets. Time to hook it all back up and have a fire. Fingers crossed. It's been a wildly frustrating (due to my lack of mechanical knowledge) journey, but a really great learning experience. I can't thank these forums enough or youtube. Thank you for your help @Washed-Up and @doneill127. And this is the youtube video that finally got me to realize that there was a slider plate my feeder arm needed to be attached to:

Glad you figured it out…and regardless of whether or not YOU think you’re mechanical…you did a fantastic job of diagnosing…that’s half the battle when it comes to fixing anything.
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