harman combustion fan won't shut off?

[ivanhoe]

My Accentra combustion fan won't eventually shut off after initiating shut down mode. It goes into shut down but the combustion fan runs & runs. It use to shut off after awhile but not no more, what gives? Now i can't do a shut down in the morning and go to work and come home with a off stove but one with the combustion fan still running. Could it be the ESP is starting to act-up?

 

[DAKSY]

My Accentra combustion fan won't eventually shut off after initiating shut down mode. It goes into shut down but the combustion fan runs & runs. It use to shut off after awhile but not no more, what gives? Now i can't do a shut down in the morning and go to work and come home with a off stove but one with the combustion fan still running. Could it be the ESP is starting to act-up?

Sure could. Have you pulled it & cleaned it? If it doesn't sense the temperature drop in the exhaust stream, it'll keep on keepin on...

 

[Don2222]

Hello

Clean the ESP probe real good and unplug it from the circuit board and plug it back in to assure a good connection. Be careful not to break the plastic clip that holds it in.

 

[ivanhoe]

Thank you, I will pull it out & clean it good. I never pulled it out before but always gave it a brush-over when doing a cleaning of the stove.

 

[DAKSY]

Thank you, I will pull it out & clean it good. I never pulled it out before but always gave it a brush-over when doing a cleaning of the stove.

You really should pull the ESP every time you run a brush through the internal vent in the stove.
That's a VERY sensitive part & the slightest bend to the sheathing will render it suspect, or worthless...
A 1/4" magnetic nut driver is the ideal tool for the job of pulling the zip screw that holds it in place.
Speedy White glass cleaner from Rutland works really well for cleaning the ESP.

 

[ivanhoe]

Finished cleaning it! As soon i plug it in, the combustion fan comes on even when in OFF position. It works when the flame is started, meaning it waits for temperature to rise before starting to feed pellets! It looks like it works on the high end of the parameter but not the low end of it!?!? Poor design when the OAK is attached, have to remove the piping to be able to pull the ESP probe out! Harman tech take note if you're chiming in!!

 

[JRegs1]

I'm having the same issue. Did you ever get it working as expected?

 

[ivanhoe]

I did replace the ESP probe but it has being a while. If I remember correctly I replaced the circuit board and the problem went away.

 

[Don2222]

I did replace the ESP probe but it has being a while. If I remember correctly I replaced the circuit board and the problem went away.

X2 - It is the Circuit Board.
I like the new Rev F Circuit Board, it has a better heat algorithm and it finally has the vacuum error 2 blinks so No More guess work when there is a vacuum problem!

 

[JRegs1]

I've exhausted all resources and wanted to know why my Harman Accentra Pellet Insert's combustion fan wont automatically turn off and continues to run indefinitely. The only way it turns off is to open the door or unplug. Here are some things I've done and noticed:

• Removed and cleaned the combustion motor & fins. (Found a quarter size piece of Styrofoam in motor mount air passage/exhaust area).
  
• Cleaned feeder chamber.
• Removed and cleaned ESP Probe with green scrub (Found a dent in probe & is slightly bent)

• While ESP Probe was removed, cleaned exhaust area.
• Followed wiring for ESP Probe back to control board & looks good.
  
• The connector on the control board for the ESP Probe pulled right off of the 2 pins. Tried leaving it off, still failed.

• Cleaned compass panel and heat exchange area.
  
• Burn pot and distribution blower cleaned.

 

[rickwai]

With damage to esp I would bet it is esp if the rest of the stove and piping is clean. It could be the board also. I typically replace esp when I replace a board regardless. That way you start w/ all fresh controls.

 

[sandpipe]

Original poster-- did you always keep your stove plugged into a good surge suppressor to prevent damage to the circuit board?

 

[ivanhoe]

Original poster-- did you always keep your stove plugged into a good surge suppressor to prevent damage to the circuit board?

Always, haven't any issues since the board replacement.

 

[JRegs1]

With damage to esp I would bet it is esp if the rest of the stove and piping is clean. It could be the board also. I typically replace esp when I replace a board regardless. That way you start w/ all fresh controls.

I was told that this is expected behavior for the Accentra Insert in the fall because it's not cold enough outside. The stove will constantly stay 5 degrees above shut off temperature. Apparently I need to buy a new board which now comes with a timer on it.

 

[JRegs1]

This is still an issue. My Harman Accentra Pellet Insert combustion blower wont automatically turn off and continues to run indefinitely. The only way it turns off is to open the door or unplug. It has been thoroughly cleaned, no status lights blinking. I've been told by Harman there is a new control board replacement part 1-00-05886, superseded control board 3-20-05374 and comes with a timer which will force the combustion blower to shut off if the ESP probe does not.

My dealer thinks its a draft problem because when I open the door, the combustion blower shuts off. Its a 4" into 6" liner. Does anyone know if this could be a draft problem?

 

[Don2222]

It is usually a bad circuit board that will cause that.

 

[vferdman]

I just solved the problem of combustion motor not shutting off WITHOUT buying a new control board. Sure enough, a new control board would have solved the problem because the triac controlling the combustion motor did go bad on the board. However, instead of replacing the entire board for north of $250, the bad triac can be replaced for next to nothing if you have the most basic of soldering and de-soldering skills. New triac from DigiKey or similar costs less than $2 and is a through hole part, not surface mount, so very simple to replace in home environment.

If you look at the board, you will see four large parts sticking up with heat sinks on them (the new board has them mounted without the heat sinks, laying flat on the board). These parts are triacs, which are solid state switches for AC. One is to control the igniter, the other three are for the three motors in the stove (feed, combustion, distribution). Q4 is the triac responsible for the combustion motor. I have determined that it was stuck "on" with the control signal being "off". The control signal in this board is directly wired to the LED on the board. So, if you see the combustion LED off, but the motor running, you most likely have a bad triac. It does not take much to replace the triac and save yourself $250. The parts are widely available from your favorite electronics supplier and I have actually bought 10 of them just to have (I am an electronics geek) and because shipping 1 and shipping 10 cost the same and is more than the cost of the part (I paif $7 shipping on a sub-$2 part, so I bought 10 of them).

I hope this helps someone out there as these stoves are great, but are getting old and need a fix here and there to keep going. My stove is from 2006 and I have owned it since 2009 or so. I had to replace the combustion motor just prior to this triac issue. The fuse in the control board blew and my motor was toast. I already had a replacement ready (because I heard noises from the old one) and replaced the bad combustion motor with the new one. However after that the not shutting off problem appeared. I imagine the bad motor blowing a fuse probably also blew the triac or finished it off. The combustion motor runs the most in this stove and I think that triac had way more miles on it than the other three.

Feel free to contact me if you want to try this. I may be able to just mail a new triac to you from my stash (if you pay the postage).

Stay warm, my friends!

 

[NHMAN1]

My Accentra combustion fan won't eventually shut off after initiating shut down mode. It goes into shut down but the combustion fan runs & runs. It use to shut off after awhile but not no more, what gives? Now i can't do a shut down in the morning and go to work and come home with a off stove but one with the combustion fan still running. Could it be the ESP is starting to act-up?

Any time that I had this problem it was mostly a really dirty ESP probe. I would take it out with 1/4" nut driver and I would use Windex and clean the probe like new. The other thing is to make sure that the wires going to the probe are not broken. Also besides checking the control board it could be that you have a problem with the blower potentiometer is dirty and not allowing the motor to completely shut off or even slow down in some cases. Good luck, just make sure you are careful with the amount of soot stuck to your ESP probe or it will be a bit tricky to pull out. Once you remove it once you will see that it's pretty simple to clean and if you need to replace putting the 1/4" SCREW back in can be a little trick if you don't use something to make sure it does fall out of your socket or nut driver.

 

[Nbird]

I just solved the problem of combustion motor not shutting off WITHOUT buying a new control board. Sure enough, a new control board would have solved the problem because the triac controlling the combustion motor did go bad on the board. However, instead of replacing the entire board for north of $250, the bad triac can be replaced for next to nothing if you have the most basic of soldering and de-soldering skills. New triac from DigiKey or similar costs less than $2 and is a through hole part, not surface mount, so very simple to replace in home environment.

If you look at the board, you will see four large parts sticking up with heat sinks on them (the new board has them mounted without the heat sinks, laying flat on the board). These parts are triacs, which are solid state switches for AC. One is to control the igniter, the other three are for the three motors in the stove (feed, combustion, distribution). Q4 is the triac responsible for the combustion motor. I have determined that it was stuck "on" with the control signal being "off". The control signal in this board is directly wired to the LED on the board. So, if you see the combustion LED off, but the motor running, you most likely have a bad triac. It does not take much to replace the triac and save yourself $250. The parts are widely available from your favorite electronics supplier and I have actually bought 10 of them just to have (I am an electronics geek) and because shipping 1 and shipping 10 cost the same and is more than the cost of the part (I paif $7 shipping on a sub-$2 part, so I bought 10 of them).

I hope this helps someone out there as these stoves are great, but are getting old and need a fix here and there to keep going. My stove is from 2006 and I have owned it since 2009 or so. I had to replace the combustion motor just prior to this triac issue. The fuse in the control board blew and my motor was toast. I already had a replacement ready (because I heard noises from the old one) and replaced the bad combustion motor with the new one. However after that the not shutting off problem appeared. I imagine the bad motor blowing a fuse probably also blew the triac or finished it off. The combustion motor runs the most in this stove and I think that triac had way more miles on it than the other three.

Feel free to contact me if you want to try this. I may be able to just mail a new triac to you from my stash (if you pay the postage).

Stay warm, my friends!

Mines doing the same thing. Was it pretty easy to check with a multimeter as well?