Harman Insert with intermittent feed

[BobB]

Hi all,
I'm trying to figure out why I'm getting intermittent feed on my Harman Accentra pellet insert stove.
The unit fires up on auto, and it feeds, but not like it used to. I just pulled it out and vacuumed everything, and it was professionally cleaned last year.
So my main question is...what does it mean for the feed light to be on, but the auger not turning?
The auger CAN turn...it turns enough to keep the fire lit, and all the fans are running with no blinking lights. But, the fire is low, and I notice the feed light is coming on regular intervals, though sometimes the feed light comes on, and...no feed.
I've adjust the feed rate...predictably that has no effect.
Final note on this unit...it never turned off well. When set to 'off' it will often burn at a really low rate, or actually go out but the fan will just never stop (well after cold). May be unrelated, but thought I should throw that out there.
I'm thinking about jumping the differential switch, but could that really be it? The feed motor light is coming on/off as it used to...just no feed sometimes.
Thanks!

 

[DAKSY]

How clean is the ESP?

 

[BobB]

How clean is the ESP?

Pretty decent I'd imagine. I've burned less than 10 bags of premium hardwood since a full cleaning.
Could a dirty ESP cause the feed light to come on but not the feed motor?

 

[Mt Bob]

Professionally cleaned "last year"?You lost me right there,pellets are dirty,you do not understand pellet stoves,have a professional come to your house.But,if auger light comes on,auger should turn,except that has been proven otherwise,if draft is low/stove/flue dirty.The indicator light is not a "guaranteed".

 

[heat seeker]

Sounds like the auger is binding, or the motor is getting lazy. If the control is calling for heat at the proper intervals, I doubt the probe is the problem.

Make sure the wiring to the motor is firmly connected at both ends; at the motor itself, and the connector on the board. You might remove and install the connector at the board to make sure there's no crud on the contacts (with the stove unplugged!).

I don't know if the vacuum switch could cause this. You could jumper the switch (for testing only) and see what happens. Your stove or venting may be plugged.

 

[miteclipse]

This happened to me when I was fairly new to my p68. My issue was that the igniter area was full of ash (never was cleaned). Loosen the 2 wing nuts and vacuum that area.

 

[rickwai]

2 scenarios can cause auger to not run when the boards calls for it (light on)
- flue/stove partly plugged. Vac switch is on the neutral side of igniter and auger. So Board sends power(light illuminates) but if no neutral (vac switch not closed) motor wont run. I have seen many Harmans that light fine but wont stay lit do to plugged flue.
- Bad auger motor only running part of the time.

If you clean burn pot out and put in test mode and watch auger turn that will tell you alot. Should make a full turn every 15 seconds. See if it turns smoothly for the whole approx 45 seconds that the test mode runs.

- A dirty stove/venting can make the stove not want to shut down also

 

[BobB]

2 scenarios can cause auger to not run when the boards calls for it (light on)
- flue/stove partly plugged. Vac switch is on the neutral side of igniter and auger. So Board sends power(light illuminates) but if no neutral (vac switch not closed) motor wont run. I have seen many Harmans that light fine but wont stay lit do to plugged flue.

Yup, it was the differential (vacuum switch). I guess it's possible the flue is clogged up top, but the thing is running like a champ with a strong flame and no smoke in any running mode now that I've jumped the switch.
I'm going to start by replacing the vacuum switch. Might throw in a chimney cleaning for the parts I cant reach with my vac hose, but the stove itself is nice and clean.