Harman P45 won't stay running

[bowyer2002]

My P45 has been recently thoroughly cleaned, it appears sealed and should be working fine - as it did last season when we quit using it.
To get it to start running I have had to manually feed the burn pot with about 1/2 a coffee cup of pellets every 5 minutes until it warms up, about 6x.
Then to keep it running the feed adjuster is set on 6. I used to keep the feed adjuster about 3.5-4.
In observing the feed indicator light and listening to the auger motor, the motor only runs about 1 second unless the adjuster is set on 6, then it runs for about 2.5 seconds.
The attached pictures are of the stove's settings and the resultant flame after being on for 30 min .

Any help of where I can do further investigation is appreciated - the local dealer is no help diagnosing the problems but will happily, "...send out a tech @ $80/hr so they can learn to work on Harman stoves!"

 

[jzm2cc]

Harmans can act weird if the voltage polarity is not correct, but I'll assume the stove is plugged into same outlet in which it used to work just fine.

Wonder if exhaust probe was bent and damaged the last time it was cleaned. Its sounds like the control board is not seeing a successful light of fire so mot feeding more fuel. When you manually get it hot for a long while it keeps going with a higher feed rate.

More clues would be helpful thiugh.

 

[bowyer2002]

I pulled out the probe, double checking that it wasn't physically damaged by my cleaning the exhaust flu.
Other than the screw being a little hard to get out, the probe looked fine.
I dont know how to check it with an ohmmeter or even if I can - but, if it's checkable, please give instructions!

 

[jzm2cc]

From what I've read the probe varies capacitance with temperature but i dont have a spec to reference. Re-reading your OP you state it feeds ok with rate turned up to 6, but not well below that. The feedrate potentiometer maybe going bad in certain positions. Try a manual start with it set in 6 instead of your normal 3 or 4 and see what happens. My past pc45 needed a really hot initial fire to get auger feeding, and then the feed rate ramped up very slowly compared with p61 or p38 units. Think this has to do with it being a corn stove which are careful about not smuthering the fires.

Anything changed from when it ran well like DIP switch positions, or exhaust restrictor plate type (corn or pellet), auger motor, etc?

 

[Bioburner]

Age of stove and any other maintenance recently? We should be able to get to the bottom of the issue. But leaning on two possible issues.
Have you done a dollar bill test on the door gaskets? While the vac switch might be satisfied so much air can leak around the doors as to keep a low temperature. I like to replace gaskets at around 5 years. Easy and cheap.
Been a rash of bad ESPs this fall.
There is three versions of the control boards I have found out first hand. If using pellets start the stove above a fuel rate of 4 so the stove thinks it going to run pellets.
The pot switch that seems to go bad the most is the on-off fan control.

 

[bowyer2002]

I was home for lunch and started the stove, fired up in the pictures.
Just getting home and it seems to be running fine WITH the feed set at 6.
I'll turn it down to 4 and see if it stays lit.

No addl maintenance to the stove. It's been running for about 7 seasons. I'll do the dollar bill test when the stove is a little cooler.

Should I pull the circuit board to look for a burned spot, etc?

Thx!

 

[Bioburner]

Well your over due for some new gaskets.
You won't see any issue with the pot switches as they are pretty self contained. I would not pull the board at this time. Pictured
I would check and clean the room temp probe connections at the back of the stove to help rule out that though very low on the probability IMO

 

[Mt Bob]

If running ok,try gently wiggleing the knobs on the pots and watch for changes.If board has something visual it prob. would not run properly,however unplug all connections and inspect,look for burns or slight corrosion.

 

[Cory S]

How is it working in Stove mode (constant burn)?

 

[bowyer2002]

I turned it down to 4 at the time of my last post and it's been burning fine ever since in room temp mode, which I usually use.

It should run all night.
I'll post my findings in the morning.

 

[bowyer2002]

Tentatively good news.
The stove operated perfectly overnight with the feed turned down to 4.
So, we'll see how things run over the next few days.
I will check the suggested contacts for corrosion and replace the seals as preventative maintenance.
Thanks for all of the suggestions!

 

[bowyer2002]

How is it working in Stove mode (constant burn)?

It didn't seem to matter if it was on Stove or Room.

 

[Bioburner]

I would get a new probe to have on hand. Not to badly priced on Ebay this AM

 

[bowyer2002]

Well your over due for some new gaskets.
You won't see any issue with the pot switches as they are pretty self contained. I would not pull the board at this time. Pictured
I would check and clean the room temp probe connections at the back of the stove to help rule out that though very low on the probability IMO

What size gasket material do I need?
My stove was hot this morning and the material wouldn't easily come out before I left for work to give me a sample.
Thanks!

 

[Bioburner]

3/8 I believe. Don't try and pull it as you lay it down but lay it in easy and almost push it to help keep its full form. A cheap drill powered wire brush makes the job of cleaning out the channel very easy and one can be had for about $5 and can make the project of doing the ash door and main door an under an hour project.

 

[bowyer2002]

Do you recommend removing the doors or leaving them in place to wire wheel the channels and install the new gaskets?

 

[bags]

Pull the door off. Lay down an old towel or such and lay the door on that on a work bench or table. Much easier and the way to do this little project. A smaller to medium flat screw driver helps also. The most difficult part is getting the old gasket glue off. Definitely pay attention as to not stretching the new rope gasket as Bio mentions.

Just glue the receiving channel and lay the rope in naturally as it is. If it gets stretched it will likely be too thin and you will end up with a poor seal. I just did my PC45's firebox and ash pan doors last fall. It is a very simple and easy to do task. Good Luck.

 

[bags]

You can pull the handle and it will lay flat or you can over hang the handle if you want. If you remove the handle there are TWO (2) set screws in there that take an allen wrench. Might be a bit tough to break loose but not real bad. Use some Anti-sieze when you run them back in. I tore my stove apart and anti-siezed everything possible. You do not have to go that far but mine was bought used and I wanted to rework, replace, or recondition everything while it was easy to do to put it back into a "new" or 100% working condition. Bio was a huge help and the job really is simple if you are somewhat mechanically inclined.

But if you are in good shape just replace the ropes and fire it up. Don't fix something that is not broken another words.

To get the door off unlatch it and just grab it and lift up so the hinge pins pull up and out. Might need to rock it and wiggle some.

 

[bowyer2002]

bags -
thanks for the quick reply, this repair should happen tonight!

 

[bowyer2002]

Well, the stove works in 'stove' mode but not reliably in 'room' mode.
When I get the seals replaced this weekend, when I have time, then I can re-evaluate.

 

[bowyer2002]

I got a new (this season's) load of pellets and my stove is now running perfectly!
In hindsight, I was using last years pellets when my burn problems arose. The dreaded six-blinking inadequate combustion light!
These old pellets had set outside, although covered, for almost 9 months and I think they absorbed moisture and wouldn't burn properly.
Thanks for all of the preventative maintenance and regular maintenance suggestions!
Have a Merry Christmas!

 

[Bioburner]

Misery has been getting more than its share of precipitation. Usually if pellets get to damp top burn they expand to sawdust. You can attempt to salvage them by setting some on pans etc by fire and blend them. Don't know how many you have.
Good luck and stay warm-dry.

 

[bowyer2002]

I had about 1/4 ton of old pellets.
I got them burned and now I'm into 'fresh' dry pellets.
There was a volume difference which was noticeable from the old to new pellets, about a 25% difference when poured into the hopper.
We'll stay dry and warm now, thanks!

 

[Bioburner]

You being a seasoned pellet burner I had not thought about bad pellets.