Loud bang followed by smoke

[Captainyeager]

Hey guys,
Got a call from the wife that she heard a loud bang from the pellet stove area and smoke began to fill the living room. She said the stove remained running after the bang and was able to turn it off. She got the smoke out of the house and noted no flames coming out of the chimney. Was this a chimney liner explosion? The equipment is a comfortbuilt 22 insert with a 3 inch chimney liner running about 14ft. The pellets are %100 platinum grade soft wood pellets. First year with the stove and haven’t had the liner swept yet. I’m currently traveling for work so don’t have any other details. I’ve burned about 25 bags of the soft wood so far and various other cheap brands of soft/hardwood mixes. Thanks for reading

 

[Northwoodneil]

Was the stove running at the time or was it during start up? It may have been smoke build up from the unlit pellets and a "woof" when they finally caught fire. The pressure of the ignition blows smoke out of every small crack and joint.

 

[Copakekid]

My P61A does the same thing if I'm lazy on the cleaning schedule. Fills up with a lot of smoke then ignites and pops and blows smoke out around the door gasket.

 

[Captainyeager]

Yeah so apparently it was on start up. I just cleaned the chamber 2 days ago so any other thoughts on why this occured?

 

[Dataman]

My XXV does similar, but no smoke in room. I like to watch it startup. It also makes loud noise when it encounters long pellet and has to chop it up. All Normal Stuff.

 

[Northwoodneil]

I'm not familiar with your stove but the woof happened to me when the startup charge of pellets was to large, smothering the flame. Maybe the stove called for heat then changed it's mind resulting a double start charge the next time?

 

[zrock]

Yeah so apparently it was on start up. I just cleaned the chamber 2 days ago so any other thoughts on why this occured?

this happens on occasion, sometimes the pellets and ignitor get lazy and their is more than usual smoke buildup in the chamber and when it does ignite the gas in the smoke ignites as well causing the boom and smoke, basically a flashover in your stove. I have a different stove and in the last 5 years i have had it happen maybe 2x when i did not get the burn pot seated properly and the ignitor was to far away from the pellets. I would not worry about it unless it start happening on a regular basis

 

[Mt Bob]

Misfire. Dirty stove and/or flue. However, some Harman's have different/improved burn pots for this reason.

 

[Captainyeager]

Thanks for all the responses! I think a combination of lousy pellets and a poorly seated burn pot created the rough ignition. Do you think it’s worth checking vent pipe seals? Not sure if that type of rapid expansion stresses the furnace tape and mortar

 

[tlc1976]

Like others I have had this happen every now and then. Whether the stove was just cleaned or is close to needing cleaning, makes no difference in my case. My educated guess is how the pellets fall into the pot. If one lands right at the igniter hole, it will probably start quickly. If they fall to form a pocket around the igniter hole, it takes longer. The longer it takes, the more smoke builds up and the bigger the poof.

And of course bang of the auger snapping long pellets, but that doesn’t result in smoke.