Ash Pan Fire

[m_kenney]

Hello everyone,
Long time listener, first time caller. We had our Harman P68 installed last march, after getting tired of getting $400 propane bills every two weeks for our circa 1860 home in Maine. It has been a great experience, with the exception of a couple of hiccups. A couple of times this fall, I have come home to my house smelling like smoke, only to find that I have smoldering pellets in my ash pan, a good amount of them. This has happened 3-4 times so far. From what I can tell, my feed rate is set correctly as per the manual, and I can't find any other reason to have this happening. We are having gale force winds here today (can't remember any significant weather events the other days), is it possible that the wind is blowing in my intake, and is blowing pellets out of the burn pot? That's all i can figure would be causing this at this point. Thanks for the help!

 

[DAKSY]

What is your feed rate set at?

 

[m_kenney]

What is your feed rate set at?

4, when I first noticed this happening, I ran the feed rate test as per the manual which gave me a satisfactory result.

 

[Washed-Up]

If you’re concerned with wind pressurizing your air intake, put a 90 degree elbow on the outside entry and put it down or away from the direction of the wind.

 

[Mr._Graybeard]

I wonder if the ignition cycle is failing. When that happens with my boiler, it reloads the burn pot with pellets even though it may already have some smoldering pellets in it -- which proceed to drop into the ash pan.

When I run across this problem, it usually means that the combustion fan is loaded with ash and can't move enough air to get good ignition. If your stove has a finned igniter, you'll also want to make sure the trap in the burn pot is clear of ash.

 

[Washed-Up]

Sounds like it’s happening fret the stove is lit and operational, could be ash underneath the burnpot too…

 

[Mr._Graybeard]

Sounds like it’s happening fret the stove is lit and operational, could be ash underneath the burnpot too…

I dunno, OP said he came home to the house smelling like smoke and smoldering pellets in the pan, so it seems like he doesn't know how they got there. Looking at the photo, fire has never touched at least half of them. I don't know how that would happen with a bottom-feeding Harman if it was lit and running.

 

[m_kenney]

I dunno, OP said he came home to the house smelling like smoke and smoldering pellets in the pan, so it seems like he doesn't know how they got there. Looking at the photo, fire has never touched at least half of them. I don't know how that would happen with a bottom-feeding Harman if it was lit and running.

I keep the stove in room temp mode, so the lack of ignition sounds plausible. Its probably a full burnpot in the pan. I should have counted the blinks of the status light to gain more information. My first instinct was to restart the stove to exhaust the smoke... i havent noticed this problem happening while im home, so during the day when it cycles on and off more than overnight.

Thank you all for your insights so far. Ill clean out the ignitor area when the stove cools. I am burning a brand of pellets that i dont normally use (upcountry hardwood, i think it is a house brand from my supplier.), they had similar specs to the lauzon pellets, but were much cheaper. Im about 2/3 through that ton. They produce more ash than anything else that ive burned. But ive read that harman stoves can burn just about anything. Ill see if it continued after I switch back to my normal pellets. I guess this is my karma for trying to save a buck.

 

[DAKSY]

Make sure you punch out all the holes in the burn pot, too. A small Allen Wrench or a piece of 12ga Romex will work well…

 

[tbear853]

Isn't there a removable plate to allow you to vacuum ash out of the chamber under the burn pot. Once mine filled with ash enough that it reduced air supply coming through the holes so the stove kept feeding pellets trying to get up to temp, and those unburned, just charred pellets were smoldering in the ash pan.

 

[m_kenney]

So tonight i let the stove cool down and cleaned out the ignitor compartment. There wasnt much ash in there (cleaned in September, not quite a ton burned since then. I only had one or two clogged air holes, but i poked through all of them just in case. I am not plugged into a UPS, perhaps the power blinked while it was starting up, causing the auger to think the pot was empty? No evidence of a power outage though. I watched closely while it started up again, seems to be operating normally. Ill report back if the issue persists. Thanks for the help!

 

[Mr._Graybeard]

I'd check the combustion fan and the surfaces around it too. That is what has caused my ignition misfires in the past.

 

[Havilcek stole the ball]

We had an incident with my P68 that has come to be not so fondly recalled as "Harmanaggedon." The igniter was getting flaky and often the pellets would overflow the burnpot without lighting. I had let the ash pan get pretty high and so the ashes acted as a high base for the unburned pellets flowing down, eventually topping out almost level with the burnpot across the whole stove. The flaky igniter decided to light at that time, and the resulting conflagration was intense. Smoke was billowing out of it an all directions inside and outside. I had to go outside to get dirt to throw on the fire to put it out. The pellet stove somehow survived but the curtains, furniture etc. took a beating from the thick smoke.

Anyway, the point is that the flaky igniter can cause overflow of pellets and if they light it can be too much smoke for the stove to handle, so that could be the cause of the smoke in the house.