Lopi Yankee Bay Insert pellet build up

[deaninMA]

i have researched but cannot find an answer to my problem. Posting as I am at a loss of where to look next.

2004 Lopi Yankee Bay
Ran perfectly until late winter last year. Pellets started building up, but not as clinkers

Always ran with regulator at 1 1/2 - 2 1/2 as exhaust got dirty after a couple of tons.

Original door gasket was showing wear, suspected air leak was causing the issue.

Removed stove and did a full top to bottom cleaning over the summer.

Replaced door gasket and glass gaskets.

Adjusted door to pass ‘dollar bill test’.

Started to run late fall, same symptoms appeared.

Pellets and ash building up in burn pot. Problem occurs regardless of heat setting.

Adjusted regulator, no difference.

Checked door adjustment. No difference.

Checked exhaust vent. No issues found.

Tried different pellets - hardwood, soft wood, blend. No difference.

Replaced control board and combustion fan. No difference.

Replaced original exhaust snap disc. No difference.

Second guessed installation of door gasket. Replaced again. No difference.

Found cracks in burn pot. Replaced with new superceded burn pot from Travis. No difference.

Checked auger active and delay times against downloaded service manual. Timing to spec.

Checked voltage output to combustion fan at different settings. All came back to spec against manual. (90/100/110/115/115/115)

Talked to backlogged services tech who told me I had done everything he would have tried. Suggested looking for draft leak in vent.

Replaced flex pipe with rigid 4in vent, sealed joints. Replaced exhaust plate gasket. That was today.

Stove ran on #2 for four hours, then started building up again in pot. Had regulator at 1 1/2.

Scraped burn pot out, adjusted regulator to #4. Started to see ash building up after 2.5hrs.

Scraped quickly, regulator now at 5.

There’s no good reason why I should be trying to run with the regulator on 5 with. A clean stove on heat setting #2.

At a loss as to what to try / look for next.

There’s no obstruction for incoming air, the combustion fan is getting the voltage as spec’d and it is new. Door passes dollar bill test. Glass does not get sooty until pellets build up.

Where else can I be leaking air? What else could be causing this issue?

Apologies for long first post, but pulling my hair out.

Thanks in advance.

 

[gutlo]

I have a Lopi Pioneer, which is the same as the Yankee but smaller. I found that keeping the air regulator all the way open is the best way to operate it. At lower pellet feed settings it makes a little smoke, but at higher settings, it burns smoke free and hot, You might try opening up the air regulator.

 

[deaninMA]

Thanks Gutlo. I've tried opening the regulator up to five with limited improvement.

 

[Ssyko]

How is the exhaust vent configured? Did you run a brush threw it?

 

[deaninMA]

4in flue outlet on stove to 45 to 6in straight to 45. 4in to 8in adapter, 8in stove pipe vertical run.

Same system has been in place since stove installed, with the exception that I replaced a short section of 4in flex pipe with the new rigid pipe.

Ran brush in vertical vent, have enough clearance to look up inside and saw nothing but daylight all the way to the top yesterday.

 

[Ssyko]

Well with the clear vent and everything else you have done, I must admit it's quite the quandary. Only thing I see is the glass seal and door alignment in your manual. Other than that I would have to start looking for cracks in the seams of the fire box itself.

 

[deaninMA]

Ssyko - thanks for your input. Going to pull the side fly ash covers, combustion blower, refractory, ash pan and burn pot out again tonight. Going to run a 1.5in flue brush into all the ash openings/cleanouts to verify nothing is blocking what I can't see or that the vac and previous brush effort didn't get. Then going to visually check the joints in the fire box, heat exchanger tubes, etc. I picked up a cheap inspection camera to run into the stove duct work as well.

There has to be something I am missing. The glass and refractory isn't getting dirty/sooty during normal burning, at least not until the pot starts to build up. It's either not letting enough air in, or pushing enough air out through the burn pot because it isn't ejecting ash/small embers like it used to.

 

[Ssyko]

I would check the alignment just to rule it out.

 

[deaninMA]

I've done the paper test more times than I can count, but I was planning on double checking that as well.

I can see a good imprint in the gasket where the gasket meets a lip, but the corners squish flat so I've been relying on not being able to pull paper out (single layer copy paper about 3in wide). It seems like I have a consistent seal around the entire door.

I had replaced the glass gaskets as well, those seemed to simple to mess up, adhesive on one side, center on edge of glass, work around perimeter and then fold the gasket to the glass faces. Those all appear to be symmetrical and consistent, and there is no movement if I try to move the glass in the door.

 

[Ssyko]

Well if the paper test is good id say the door seal is good. You said you changed the “combustion fan” did you just change the impeller or the whole blower assembly?

 

[deaninMA]

Ssyko - thanks for sticking with me on this.

I went back to basics last night to check everything in a methodical manner based on your posts.

I had previously pulled the side fly ash doors on the sides, stuck the vacuum wand in, looked to see loose ash was removed and moved on.

I found a flexible 1.5in conical flue brush yesterday and hit the area behind the fly box from inside the fire box and in from each fly ash door. There was build up in the center of the stove above and below a tube that passes through for the igniter. The vac wasn’t clearing it out that far in.

I also rechecked the door and it was slightly tight on the latch side. It was passing the paper test, but not in perfect alignment.

I put everything back together and the difference was literally night and day. Flame looks like it used to, small embers and fly ash are being blown from the pot.

Thanks for the help.

 

[Ssyko]

Nice! Glad its back to normal. Stay warm and have a great New Year!

 

[deaninMA]

Thanks again for your help. You have a great New Year as well!!