Pellet Stove Burnpot Overfilling

[homebrewz]

I've burned wood for several years, but this is my first year with a pellet stove. I have a Breckwell P-23FSL. It has different operation levels rather than a thermostat. If I have it on the middle level or higher for more than 10 hours (overnight) the burnpot seems to fill up to the brim with red hot coals of burned pellets, so much so that some new pellets are bouncing off the top and into the ash pan, unburned when dropped into the burnpot. The manual recommends sitrring the burnpot daily, and I do that, but it doesn't seem to help. Whenever I start the stove from cold I always clean the burnpot and make sure none of the air flow holes are plugged.

Is this typical for a stove like this? Is there something I can do to prevent this? I was thinking maybe some of the pellets are too short...could have gotten broken up in the bag when I was loading them into back room. Would that make a difference? FWIW, I'm burning Allegheny hardwood pellets.

Thanks for the help,
Bernie
Howes Cave, NY

 

[begreen]

Sounds like the feed rate is too high and needs to be adjusted down a bit.

 

[Corie]

Feed rate needs to be adjusted in proportion to underfire air (or draft).

I'm almost 100% certain there is an adjustment somewhere on that stove where you can increase the air coming from under the pellets. Higher feedrates mean more underfire air. If you've tried that and still have that problem, you should contact the dealer, because the stove should be able to operate at any feed level for any period of time, assuming the underfire draft is set correctly.

 

[homebrewz]

Is the underfire air control the same as the damper control? It has a side pull out for the damper control.

 

[Corie]

yeah that sounds like the same thing to me.

Where is your setting at?

 

[homebrewz]

I usually keep it halfway out. The manual says to keep it halfway when firing up. If its all the way out, it produces a strong, torch like, yellow flame and if its mostly in, the flame is a lot more subdued. Which type of flame/setting is best for pellets stoves? The manual is very vague. I'll try to experiment.

Thanks, I was thinking you might mean it was some sort of internal adjustment, but the damper control rod is right on the side. Incidentally, I'm just using the air from the room its in. There is no external draw from outside for intake air.

 

[Corie]

We used our pellet stove on room air as well. Our house isn't terribly well sealed, and it was never a problem.


Now, the key to adjusting your draft is simple. The breckwell operates on a top feed design principle, like the jamestown we had so I am well advised on the damper control.

The key is a blow torch like flame, BUT you don't want pieces of flaming pellets being ejected from the burn pot. The idea is to keep the draft low enough that when the pellets are finally expelled from the pot they are mostly burned. In our jamestown, the burn pellets being ejected from the burn pot were smaller than a BB and never flaming. The red hot pellets should remain in the burnpot, unless a fresh load of pellets is coming down. That's when the majority of the burnt pellets are cleared from the pot.


You want the flame stiff and blow torch like, with all the smallest of the burning pellets being thrown from the burn pot. Different feed rates and different pellet brand will effect this.

I'll post a picture of what your flame should and shouldn't look like after dinner.

 

[Corie]

Yes

 

[Corie]

No

 

[homebrewz]

Ah, I see what you mean. Thanks for posting the photos. The manual had said to reduce "blow torching", push the damper in to adjust. By this, I was under the impression that blow torching was bad. I guess they meant serious blow torching.

I may also try replacing the door gasket. Its not passing the "dollar bill test" in a couple of spots...might be contributing to the problem.

Thanks again,
Bernie

 

[Corie]

yeah the door gasket could be a problem too. Without a proper seal, you don't get the positive pressure in the firebox.

I thought the stove was new though? It shouldn't need any new gaskets

 

[homebrewz]

No, sorry to give the impression it was new. Its about 5 years old. Found it in the paper last fall. I needed something to supplement the heat in the other end of the house (opposite the wood stove). From the looks of it, the previous owners took good care of it.

I was surprised I could pull the dollar out from the door in places because the gasket still looks brand new.

 

[Corie]

AHHHH, gotcha


nevermind then

 

[N-gree]

Your stove sounds like it needs to be regasketed - there's around the door, which is always number 1 place to look.

What's happening to your stove is the air is being drawn from places other than underneath the burn pot, and only burning the top pellets, leaving the bottom coals starved for air. They will get so hot from lack of air that they will melt the impurities to the burn pot, and will not turn to ash and blow out, therefore building up in the fashion u describe. Other places to look for bad seals are the combustion fan, removable ash pan underneath burn pot (if part of the vacuum envelope) and around the damper. I've seen designs even have areas around the pellet down chute open thru the rear firewall and need to be stuffed with rope gasket to burn properly.

You can use aftermarket gasket material like metal imbedded non-asbestos fiber gasket for around the combustion fan, where you can cut your own shapes, and is very durable, unlike the flimsy stuff supplied by stock. A thorough teardown and regasket is something I would suggest when acquiring any used stove, or when bad burn qualities are observed. Incidentally, if the combustion fan was "push" rather than "pull" there would never be a problem like this, and believe me its very common.

Jason

 

[begreen]

Interesting info N-gree. The Quad inserts have adjustable door tension and a vacuum pressure sensor, so it never dawned on me that the Harmon could be pulling air in for combustion from the door gaskets.