Harman auger shutting off

[kilarney]

The feed motor on our Harman Accentra insert has shut off from time to time. The Feed Motor light is lit, but the auger does not turn.

I finally figured out what is happening. When I lift the lid to fill the hopper, the auger stops. (Makes sense.) On occasion, when I shut the lid, the stove does not register that the lid has been shut. Thus, the auger remains off.

So a couple of questions:
1) Has anyone else had this happen?
2) Where is the sensor and/or contact? I'm wondering if some sawdust has gotten in the way.
3) Is there a "fix", or is it just a matter of making sure that the sensor/contact is free from interference?

Thanks!

 

[Steve NH]

Mine problem is similar. on a P68

1st there is a neg pressure sensor in the hopper, It senses when there is or is not a slight vaccum in the hopper. (mine is as looking in =bottom left corner)
- it appears to me that what that does - when the combustion motor is runing there is always some draw (vaccum) in the bin (air being forced out of the firebox - draws some thru auger)
- When you open the bin that vaccum is lost - sensor notices it and shuts off auger. But as soon as bin is shut auger should resume

My problem is similar except the feed motor light does not show that the auger should be running.
Also it does not always correlate to the hopper bin having been opened. Sometimes it just does it.

If I reset it all works fine.

My stove is new and under warrenty - I have a call in but since the problem is not predictable I've put the service call on hold.

So at this point I have no answer.

Anyone else?

 

[kilarney]

Ahh... that must be what's happening with me. I just assumed that there was an actual sensor to determine whether the hopper door was shut. But the pressure sensor makes perfect sense. I just knew that it was correlated to opening the hopper door.

I wonder if it's as simple as not having a clean seal when I shut the door due to a pellet or sawdust getting in the way.

 

[crausch]

I know you have a Accentra Insert but I think this still applies from my Advance manual:

The Low Draft Pressure Switch is a differential pressure switch that senses the pressure between the firebox and the room. If the pressure becomes too low for proper combustion, the switch opens, cuttin power to the feeder motor and the igniter element. This switch is connected into the AC (high voltage) wires; therefore, the control may show the feeder motor and igniter lights "on" but they are not operating.

Your stove works with negative pressure in the firebox. If the Hopper lid or ash pan is not sealed in place than this safety feature kicks in. I am not sure why the last line of the quote says your control "may" show the lights on. I would think this should be the same for all stoves but it may explain why your lights are on and Steve's are not.

[Edit] You must keep the seal at the hopper and the ash pan clean so that they form a good seal. I usually take a damp cloth and just lightly rub over the hopper seal whenever I fill up with pellets. This keeps any dust build up from happening.

 

[GVA]

Sensor in the hopper?????
When the heck did that happen......
what does it look like?
anyone else know about this?

As far as the indicator lights for the auger and or ignitor.............
The board tells them to run.........
the leds are tied to the board and see the output is going to the auger or ignitor.
so power is applied to the auger if the led is lit....
the vacuum switch when not being held closed by the draft will open and break the neutral from the auger and ignitor..
120vac---------board-------output--------auger-------vacuum switch-----------neutral
making a neutral float like this is not a good way of controling this...
Hope this makes sense

 

[slink]

Sensor in the hopper?????
When the heck did that happen......
what does it look like?
anyone else know about this?

As far as the indicator lights for the auger and or ignitor.............
The board tells them to run.........
the leds are tied to the board and see the output is going to the auger or ignitor.
so power is applied to the auger if the led is lit....
the vacuum switch when not being held closed by the draft will open and break the neutral from the auger and ignitor..
120vac---------board-------output--------auger-------vacuum switch-----------neutral
making a neutral float like this is not a good way of controling this...
Hope this makes sense

Harman has added a vaccum port in the hopper so the feed shuts off if the hopper lid is open. Its a running update and a required retrofit on older stoves.

 

[slink]

[
Hope this makes sense[/quote]

Harman has added a vaccum port in the hopper so the feed shuts off if the hopper lid is open. Its a running update and a required retrofit on older stoves.[/quote]

Sorry not a required retrofit. long day in the shop.

 

[GVA]

won't the fines want to get sucked into this port?

 

[AndrewChurchill]

Does anyone know if there is a similar pressure sensor on the PB105? I'm having the exact same problem with my PB105.

 

[JBogdon]

I have the Harman Accentra pellet stove.I don't know if the insert is any different, but opening the lid for the pellets has nothing to do with the auger working.Again. I am not familiar with the insert.

 

[bungalobob]

Sensor in the hopper?????
When the heck did that happen......
what does it look like?
anyone else know about this?

As far as the indicator lights for the auger and or ignitor.............
The board tells them to run.........
the leds are tied to the board and see the output is going to the auger or ignitor.
so power is applied to the auger if the led is lit....
the vacuum switch when not being held closed by the draft will open and break the neutral from the auger and ignitor..
120vac---------board-------output--------auger-------vacuum switch-----------neutral
making a neutral float like this is not a good way of controling this...
Hope this makes sense

Got My Harman a few weeks ago, A P-68, it was manufactured October 08, it has the the sensor in the hopper, and is in the manual as a safety device. It's a about a inch and a half tall and maybe an inch wide, off to the left side of hopper when facing from the front.

 

[GVA]

Does anyone know if there is a similar pressure sensor on the PB105? I'm having the exact same problem with my PB105.

responded to in the boiler room......

 

[lecomte38]

Opening either the top or the front door breaks the vacuum and will stop my insert auger. I use this feature to reposition the auger when scraping the end of the auger tube.