Harman Advance shutdown slowly, feeding pellets when off

[Davinjw]

Hey guys,

Did some searching and can't find an answer for this one:

My Harman Advance seems to be staying on too long. My room temp is in the low 70's, turned the temp knob down to 55 and he room/stove temp knob to off and the stove continues to feed pellets and stay burning for quite some time.

I played with the room/stove temp pot and got these results:

With the knob set to low room temp, status light is on, combustion fan is on, distribution fan is off, power light is on.

With the knob set to low stove temp, status light is on, combustion fan is on, distribution fan is on, power light is on.

With the knob set to Off, status light is off, combustion fan is on, distribution fan is ON, power light is on.

Continues feeding pellets for hours.

Any ideas?

Thanks,

Davin

 

[alternativeheat]

I believe the Harman way of shutting down is to trickle a few pellets in now and then to keep from burning too far up the auger screw/tube. My P61 takes a good 1/2 hour to shut down, if not longer. The first ten minutes probably, does that pellet trickle routine as well. But we don't get hopper fires either LOL.

 

[railfanron]

You sure it's not set to manual mode. In manual mode it will shut down to low fire. In automatic mode it will shut right off.
Ron

 

[Oregun]

I believe the Harman way of shutting down is to trickle a few pellets in now and then to keep from burning too far up the auger screw/tube. My P61 takes a good 1/2 hour to shut down, if not longer. The first ten minutes probably, does that pellet trickle routine as well. But we don't get hopper fires either LOL.

What you wrote pretty much describes how my XXV shutdown last night.
But what good does it do to trickle out a few pellets when they will be replaced by new pellets behind them?
It took about an hour for mine to shut off the blower since it keep feeding for for about 10 minutes.

 

[alternativeheat]

What you wrote pretty much describes how my XXV shutdown last night.
But what good does it do to trickle out a few pellets when they will be replaced by new pellets behind them?
It took about an hour for mine to shut off the blower since it keep feeding for for about 10 minutes.

Can't answer that for ya.

 

[Tonyray]

my P61A will take 45 minutes or so to completley shut off...
most of that time is the exhaust blower running...
if I want to clean the stove and I get antsy,
I just open the door for a few minutes [releasing heat] after there are no more glowing pellets or smoke.
I then shut the door and stove goes off in about 10 seconds.

 

[alternativeheat]

my P61A will take 45 minutes or so to completley shut off...
most of that time is the exhaust blower running...
if I want to clean the stove and I get antsy,
I just open the door for a few minutes [releasing heat] after there are no more glowing pellets or smoke.
I then shut the door and stove goes off in about 10 seconds.

I don't even wait for the pellets to stop glowing, I scrape them off into the ash pan. I think it's from so many years of poking into coal fires, now talk about hot ! But it's part of the deal with hand fired coal stoves.

 

[Oregun]

Can't answer that for ya.

I think I figured it out, when its working right ...
When you turn off the stove the little door closes and stays closed so no more pellets can drop into the auger.
Then the auger keeps rotating until all the pellets in the auger are in the burn pot.
Then the pellets burn down and the fan continues until the temps drop low enough to turn off the blower.

 

[alternativeheat]

I think I figured it out, when its working right ...
When you turn off the stove the little door closes and stays closed so no more pellets can drop into the auger.
Then the auger keeps rotating until all the pellets in the auger are in the burn pot.
Then the pellets burn down and the fan continues until the temps drop low enough to turn off the blower.

Could be, I never watched closely enough to assess the situation personally.

 

[MuchoBueno]

My p35i takes a long long time to completely shut down. It trickle feeds pellets for a while then it stops. The exhaust blower stays on for over an hour or maybe even nearly 2 hours until the burn pot is warm to the touch. Completely normal. It's all in the manual.

 

[Davinjw]

Today my wife was home with the stove, first warm morning in a while so she went in the living room, turned the temp down to 55* and the room/stove temp to OFF. That was at about 8am. At 1 pm it was still burning pellets and running the distribution fan, finally shut down completely at 3:30pm.

She had the windows and door open it was so warm.

It's been pretty cool lately in the NW so we may not always notice the slow shutdown cycles. Sometimes we twist the temp knob down to 60 and it stays quite a bit warmer than that for a long while.

 

[Oregun]

Sounds like it's time for a new controller board. Or maybe cleaning the switch.

 

[bags]

It can take some time for the stove to completely shut down and it is normal. I've noticed it can vary just like the ignition process starting up due to different pellets, cleanliness of the stove and burn pot, and so forth. Some times seem faster than others at least here in my case and I have two Harmans to compare. I will say that my newer 2014 P68 shuts down and responds much quicker to changes or inputs than the older 2006 PC45.

The 45 can take a very long time shutting down comparatively speaking. Could be the newer board or tech with the 68 is more efficient. It could also be many other variables such as current temps both inside and out or which mode and settings you are running in while shutting down.

 

[Oregun]

It can take some time for the stove to completely shut down and it is normal. I've noticed it can vary just like the ignition process starting up due to different pellets, cleanliness of the stove and burn pot, and so forth. Some times seem faster than others at least here in my case and I have two Harmans to compare. I will say that my newer 2014 P68 shuts down and responds much quicker to changes or inputs than the older 2006 PC45.

The 45 can take a very long time shutting down comparatively speaking. Could be the newer board or tech with the 68 is more efficient. It could also be many other variables such as current temps both inside and out or which mode and settings you are running in while shutting down.

Are you saying the OP's 8am - 3:30pm is a normal shutdown time, that seems defective to me.

 

[bags]

Are you saying the OP's 8am - 3:30pm is a normal shutdown time, that seems defective to me.

No. Not normal. I have seen my PC45 take the better part of an hour but never timed any shut downs with a stop watch.

I stated some time not all day. The 68 usually shuts down within 30 minutes or sometimes as short as 10 minutes. The 45 can take much longer than the longest on my 68. I wasn't super clear about specific times.

Could be pot switches or the board or it could be a fluke unless every time he shuts down it takes all day.

 

[Lake Girl]

ESP not reading temps accurately? Remote sensor?

 

[Davinjw]

I will take a look, this morning I shut it off and it stopped fairly quickly.

Only weird part for me is the status lights follow with the turn of the pots, I can gain or lose status light by playing with temp or the room/stove temp knobs.

I may replace the EGT probe as an attempt before I replace the control board, possibly damaged it while cleaning?

 

[Lake Girl]

Potentiometers (pots) can be changed out if the lights are varying with the changes on control knobs. The pots do get dead spots over time. There are board repair services that is a cheaper option than a new board. Pots can be purchased and replaced if your soldering skills are good or you can find a computer/electronic repair service who will do it for you.

Edit: There are also triacs on the board but their function escapes me ... electronics not a specialty.

Some repair services:
http://pelletstovecontrollerrepair.com/
http://api-assembled.com/support/support.htm

While it is a different model Harman, you might find the post interesting particularly the final entry...
https://www.hearth.com/talk/threads...ing-help-and-information.137772/#post-2147281

Bioburner's post #16 of the thread:
https://www.hearth.com/talk/threads/harman-control-board-question.155945/#post-2109848
"ebay seller, thibs23, 3 100k pots for $27. Search "harman pellet stove parts" Thats where I got my last ones"