What happened here?

[ohlongarm]

Started up the king at 4:30pm,stovetop 275,cat dead but small bed of coals maybe an inch,scraped equal amounts to the side and run a tunnel up the center and loaded all my wood,ash 22 yrs old.The usual smoke was streaming from the chimney as I was still outside working.About 5pm we started to smell what smelled like burning plastic and the stove was struggling to fire up,opened the door to air the house out,looked at my chimney,masonry lined with steel,no smoke?but small red hot embers bouncing off the cap on the inside still baffled,wife heard a pinging inside that sounded like pebbles rattling on the pipe inside.Suddenly I saw a fireball erupt inside the cap and the,smoke started pouring out big time,inside the stove was really starting to fire,checked temps on the double wall inside with IR,200,to 212 all the way up,face of stove was at 387 right ,and about 430 left,cat now was at 550 so engaged her and the stove is back to normal,plastic smell rapidly dissipating. Chimney was cleaned in October,what the hell happened here and what should I do. Thanks.

 

[rdust]

The "pebbles rattling" sounds like something burning in the pipe or chimney. I've heard it sounds like popcorn popping when something lights off. Might be a good idea to pull the pipe and look for any evidence of something burning inside it.

I have to watch my stove when the cat is bypassed, I never leave it until I close the bypass. The flame will get pulled straight up the pipe and I've overheated the pipe once or twice on windy days. If the pipe or chimney was dirty I'm sure it could've caused a chimney fire, one time was the day after I cleaned it. Now I always turn my air down to 2 1/2 or so if the bypass is open. I try to load the stove so a bigger split is right under the bypass opening so flames don't have a straight shot up.

 

[begreen]

Sounds like some creosote may have fired off in the stack. Inspect the flue as soon as you can. How's the wood that you've been burning so far?

 

[ohlongarm]

Sounds like some creosote may have fired off in the stack. Inspect the flue as soon as you can. How's the wood that you've been burning so far?

Wood is all very dry ,what caused the plastic burning smell,creosote?Thanks

 

[Ashful]

Sounds like the pipe was plugged with something, which eventually burned up. The question is... what? Any chance something got in thru the top? Seen your housecat recently?