Fire behind the burn pot of a Harman Accentra FS...

[HARMAN ACCENTRA2]

Hi

I have a Harman Accentra2 FS pellet stove .
Have had an ongoing issue with a fire burning behind the flame guide and on the sides and underneath the burn pot. I would see burning pellets drop from the back and fall into the metal shelf that surrounds the burn pot... then the pellets started piling up on the sides of the burn pot on the metal box/shelf I would have to knock them down into the ash pan to stop the burning...and actually at times it would move the flame guide off of track and into the burn pot...

Have already replaced
burn pot gasket,
flame guide
and esp
None of which helped...

Have had Harman tech here he said stove , burn pot .vent pipe all were clean... no holes clogged ignitor area & fines box clean... checked draft etc... replaced door gasket ( even though he said it looked good )
Replaced burn pot which was worn but still a flame behind the burn pot from time to time... It is much better as it is much smaller than the raging flame that filled the entire box around the burn pot previously . And I do not see any pellets accumulating on the metal box/shelf.

Anybody with any experience of dealing with this or any suggestions from anyone would be greatly appreciated...

 

[jackman]

Can you post a pic? I've never seen that problem with my stove.

 

[SmokeyTheBear]

If the burn pot was worn/warped a bit and replacing it helped somewhat what are the chances the flame guide is also worn/warped a bit as well and you have the issue half fixed as a result?

Just tossing something out there.

 

[HARMAN ACCENTRA2]

Can you post a pic? I've never seen that problem with my stove.

Jack

Here are 2 pics Hope this helps. 1 is of the flame outside the burn pot The other is of the pellets that were burning on the sides...

 

[HARMAN ACCENTRA2]

If the burn pot was worn/warped a bit and replacing it helped somewhat what are the chances the flame guide is also worn/warped a bit as well and you have the issue half fixed as a result?

Just tossing something out there.

Hi Smokey
Thanks for the reply unfortunately we did replace the flame guide. I currently have 3... No improvement other than when we replaced the whole burn pot weldment ... but any and all thoughts are welcome as this is driving me crazy... ;-)

 

[SmokeyTheBear]

Looks like a air/fuel issue.from the colors I'm seeing here.

Hopper gasket if any, slide plate, any signs of smoke in the hopper?

Gaskets if any on any covers to things like the fines box, igniter. Warped igniter cover? Fines box cover right side up or around?

 

[HARMAN ACCENTRA2]

Looks like a air/fuel issue.from the colors I'm seeing here.

Hopper gasket if any, slide plate, any signs of smoke in the hopper?

Gaskets if any on any covers to things like the fines box, igniter. Warped igniter cover? Fines box cover right side up or around?

No smoke in hopper.
Harman said all gaskets were good and the hopper gasket shows no signs of deterioration and makes a tight seal...
Just double checked fine box cover it is correct.
When I opened hopper lid red ashes/sparks fly around ( they don't when it is closed ) don't know if that tells you anything ? Also flame gets a little smaller...
NOTE : Those pics were from before we changed the burn pot and the stove definitely was not operating normally ...don't know if that makes a difference ... here are 3 pics I just took now... do you see anything different ?

 

[HARMAN ACCENTRA2]

Looks like a air/fuel issue.from the colors I'm seeing here.

Hopper gasket if any, slide plate, any signs of smoke in the hopper?

Gaskets if any on any covers to things like the fines box, igniter. Warped igniter cover? Fines box cover right side up or around?

oops forgot to mention a new ignitor cover came with the new burn pot weldment ...

 

[SmokeyTheBear]

This one https://www.hearth.com/talk/attachments/sam_1906-jpg.155260/ looks better than the other two which look like the door is open or cracked But digital cameras also distort pictures of fires.

I have one where the foreground and back ground are rock solid stable but the flame is aliased several times and above the stove.

 

[SmokeyTheBear]

Just for giggles:

 

[HARMAN ACCENTRA2]

Actually they were all taken within seconds of each other just different distances from the stove lol ... I put the 3 there because I saw a huge variation of color and wondered what difference if anything the camera was capturing... but I did not have the door or hopper lid open in any of them... and in person the color of the flames looked similar but big difference in color on the pics.
did not know digital distorts fire pics ;-(
Sorry

 

[MountainSean]

It looks to me like the fire is burning too far to the rear of the burn pot. I would try adjusting the combustion trim pot down on the back of your control board so it has a little less air. That should cause the pellets to burn more towards the front portion of the burn pot. Are you also getting excessive carbon build up or wear on your auger shaft?

 

[HARMAN ACCENTRA2]

Just for giggles:

View attachment 155263

ohhh Wow Hope there are no insurance agents on here next thing we will read is how dangerous pellet stoves {citing pictures don't lie } are and our premiums will go through the roof ... LOL !

 

[SmokeyTheBear]

Actually they were all taken within seconds of each other just different distances from the stove lol ... I put the 3 there because I saw a huge variation of color and wondered what difference if anything the camera was capturing... but I did not have the door or hopper lid open in any of them... and in person the color of the flames looked similar but big difference in color on the pics.
did not know digital distorts fire pics ;-(
Sorry

Yeah it is all that fancy processing software that needs to get out of the way.

 

[SmokeyTheBear]

What is your feed rate set to?

 

[HARMAN ACCENTRA2]

It looks to me like the fire is burning too far to the rear of the burn pot. I would try adjusting the combustion trim pot down on the back of your control board so it has a little less air. That should cause the pellets to burn more towards the front portion of the burn pot. Are you also getting excessive carbon build up or wear on your auger shaft?

Thanks will try adjusting that as I did notice when it was just maintaining heat on low burn it was burning deep in the throat...
nope no build up at all on the auger / tech said it looked good ... no problems he could see...

 

[HARMAN ACCENTRA2]

What is your feed rate set to?

feed rate set at 4... and the pellets do come out farther when it is calling for more heat ( today just happens to be a warm day here so it is for the most part just maintaining room temp... not calling for alot of heat... when it does our ash line is about 1" from the edge of the burn pot...

 

[SmokeyTheBear]

Sounds like Sean may have a possible cure then. Snap a few pictures of the burn pot when clean if you get back in there to make a change.

 

[HARMAN ACCENTRA2]

Sounds like Sean may have a possible cure then. Snap a few pictures of the burn pot when clean if you get back in there to make a change.

Not sure of what you want me to take a pic of ? The burn pot was just installed a few days ago ...
also I am not sure where in the burn pot the fire is burning would make the flame go behind the flame guide ? even if it burns further out the fire is still going to be all the way to the back where the pellets are feeding... I still think pellets are getting behind the guide somehow ... or is my thinking wrong ?

 

[jackman]

The pics don't look too alarming to me. I'd recommend you lower the feed rate and see how it burns for a while. I keep my feed rate at 3 1/2.

 

[SmokeyTheBear]

The surface of the burn pot so we can see the hole pattern.

Air flow will pull the flame towards it.

The fire will be where there is enough air and heat to make the pellets burn.

 

[HARMAN ACCENTRA2]

Hi
Well the stove has started going crazy again burning a huge fire outside the pot ...
woke up to flames shooting out the entire length of the bottom of the burn pot ( underneath not in the pot )
and now the pellets are being pushed off the burn pot without even fully burning...
This makes no sense as I turned the feed rate down to 3 1/2... it should have done the opposite...
Sorry can not get pic of this because it is too low to take a pic through the window and if I open the door the fire burning below the burn pot goes out... but the flame coming out below the burn pot were as big as the flames in the burn pot shooting towards the door
Have call into Harman tech that replaced the pot but like I said I have no faith in him...
Tried calling Harman customer service ... They are useless don't think I will be buying anymore Harman products in the future... If one can't get knowledgeable techs or at least try to help customer then this customer will not be giving them my money... Rant over sorry...
Harman stated they only talk to service reps and they have to be standing in front of my stove to make the call...
I informed them the tech has been here 3 times and has never called them and they told me to make him call
Also forgot to take pic when I had stove off... but here is the burn pot they installed if that might help you ... http://cdn3.volusion.com/2umyp.x9e76/v/vspfiles/photos/1-10-08736-6.jpg?1403191687...
Any suggestions after these new happenings ??? I am at a total loss...
Thanks for any help

 

[jackman]

Hmmmm, I think it's a different problem. The stove is over firing. Are you running in room temp mode or stove temp mode? Try running the stove in a different mode to see how it behaves. I'd also turn the feed rate down to 3 or even lower to see if that is making any difference at all. You mentioned earlier that the ESP was replaced with no change in performance. The problem could be the room temp sensor or the control board.

My stove runs nearly all the time in room temp mode at a feed rate of 3 1/2. This keeps the fire in the back of the burn pot. Burning pellets never drop off the pot. I would expect your stove to behave the very same way.

 

[HARMAN ACCENTRA2]

Currently we are running in Room temp mode...

When all this was going on a few weeks ago (waiting for service call & then waiting for part to come in )
We changed it to Stove temp. and the pellet feeding seemed to be more uniform ( that was the reasoning behind changing it to stove temp)
So the pellets would not push on the flame guide & move it out of place ... it still would eventually do the same things but it just seemed to be longer amounts of time until they happened and needed adjustment in stove mode.
I had searched through and read other posts on here and came across 1 of them that had suggested running in Stove mode for a more consistent pellet feed rate vs room temp where it was constantly changing what it was calling for depending on the temp of the room...That is why we tried it then...

Should I put it in Stove mode again and see if it changes anything ... or does what it did before give you any clues as to what is going on...
When we mentioned this to tech ( could there be something wrong with feed rate ) he said just leave it on 4 feed rate does not do anything ???

last night when I saw that it was overfeeding I adjusted the feed rate down to 2 and I still woke up with it pushing pellets over the front... so I lowered it to 1 this morning and finally a few hours later it has gradually moved back ... but the temp outside is also getting warmer so could be coincidental...

note... now that I think about it...it seems like when it is very cold outside ( as it was last night) and the stove calls for a larger fire, perhaps something is getting stuck or malfunctioning because once it starts feeding pellets at a higher rate it seems to go haywire feeding pellets ...

 

[jackman]

It's sounding more likely you have a problem with the potentiometers on the control board. This is a common problem with Harman stoves. The "pots" develop dead spots. Sometimes rotating the knobs quickly can clear the dust but I had to replace mine after about the 5th year of ownership. BTW, how old is your stove? On my stove it became apparent when the auger motor would pulse pellets into the hopper even though the stove was turned off. Do a search in this forum on potentiometer and you'll get lots of info.

If you're handy with a soldering iron you can replace them for less than $10. Your stove tech will likely charge you a few hundred to replace the whole board.