What Happened This Morning?!! WEIRD!

[michiganwinters]

So, I woke up freaked out!

Just another standard morning 8 degrees outside and 15mph winds.....until....

Husband gets up a bit before me, does the standard rake coals forward fills firebox gets them charred up a bit......and then that's when things got weird!! We sometimes get a hot smell and damper it down stove top temps settling in at 625 or so.

He said her heard some noise sounding like there were wood chips dancing in the chimney. It went of for a minute or so and lasted 5-10 minutes. I wake up to the smell of "hot" and see smoke in the air. It wasn't wood smoke it was burnt paint smell like curing. There was no excessive firebox draft when this and air was shut off due to it just being odd. Firebox burn looked like nothing special and we've seen more active burns.

We don't have a stack probe but I'm thinking we should install one.

Guesses on what happened here?? And any suggestions on preventing or changing our technique?

Stats:
-3-4yr seasoned mix of oak. Split, stacked in covered wood shed for 3+yrs so good dry wood
-We've been burning 24/7 for 7yrs. Same technique every time
-PE Summit installed this fall
-13 ft of double wall black interior with (2) 45 degrees (off set for truss). Approx 12-14 ft of doublewall class A.
-No cold air intake from outside, drawing from inside the house.
-We run our stove at 575-625 several times a day and in our past house never got anything more than a cup of dust and a few flake after a full season of burning.

 

[pen]

Sounds like a small chimney fire.

 

[blades]

Yep, small flue fire. Likely at one or both 45 offsets. Hear of it more often in 90 deg turns.

 

[Sunfish]

Yep. Chimney fire.

 

[Jags]

Great detailed info. I find one piece missing. When was the last sweep done?

 

[michiganwinters]

Its a new install from this fall so this is the first year of burning. A sweep has not been done. Is there any changes I need to make to the technique since it has the offset? Never had any issues in out last run but it was straight up.

 

[pen]

You mention running 575-625 a couple times a day. Do you let it cruise there? Or do you turn the air down once you hit that point?

 

[Jags]

Is there any changes I need to make to the technique since it has the offset?

Well...if you did in fact have a chimney fire, then the answer is yes. I would probably start with a more frequent inspection routine. Monitor what is going on and make burning adjustments to correct anything you see wrong.

ETA - even a seasoned pro has a bit of a learning curve with a new stove/install. Each and every one will have its own "personality".

 

[michiganwinters]

No stove tops cruise there. Here is a typical reload procedure. Rake coals to front, open air up all the way, close door let wood char until stove top gets to around 400, damper down fully and stove climbs to 600+ with secondaries. It will continue to burn at that temp until off gassed and temps will continue to decrease after that.

 

[michiganwinters]

Repeats as needed

 

[pen]

That sounds reasonable. Does it take long to jump from 400 to 600 if you close the air fully at 400?

I'm wondering if you have such a strong draft that even at 400 you are sucking flames up around that baffle and up the flue overheating the flue before the stove really warms up? Or the opposite, and the stove is taking too long here (stalling) from 400 to 600 since the air was shut down in one movement.

Also was that exactly what happened this morning? Or was the air left open a longer period of time?

Only thing that surprises me is most people find they need to turn their air down in 2 or 3 stages rather than being able to go straight from wide open to shut down.

A flue probe wouldn't hurt a bit, as it's just another tool to help understand what is going on.

pen

 

[michiganwinters]

I usually do but maybe things were a bit different this morn. Also went outside and now the smoke smells funny if that makes any sense.

 

[pen]

Creosote has a pretty unique smell. If the stove is burning cleanly, there should not be any visible smoke (visible condensation if really cold, but no smoke). Is there actually dark smoke now? Is the smell a hot metallic smell? Or a, well, creosote thick nasty burn smell?

 

[pen]

What's confusing here is that nothing stands out as a failure, it sounds like you have good practices.

If it wasn't an actual flue fire, it is possible to have creosote peel off and "rain down" a bit if things were to get overly hot,,,,, as in the air was left wide open for too long.

If this were me, if there are no signs of a problem still actively happening, I'd let the unit burn out and sweep the chimney / inspect everything (making sure no joints are loose) etc.

Definitely weird, but with a new setup this is hard since you have no baseline cleanings to compare to.

 

[begreen]

The main change to make in the short term is to clean the chimney more frequently. If the wood is only semi-seasoned sweep after a cord of wood is burned. The long term plan should be to get ahead on the woodpile. Ideally you have 2-3 yrs of wood stacked. Oak and hickory take a couple years to season well.

 

[pen]

The main change to make in the short term is to clean the chimney more frequently. If the wood is only semi-seasoned do this one per cord of wood burned. The long term plan should be to get ahead on the woodpile. Ideally you have 2-3 yrs of wood stacked. Oak and hickory take a couple years to season well.

Sounds like that is exactly what the OP is working with

Stats:
-3-4yr seasoned mix of oak. Split, stacked in covered wood shed for 3+yrs so good dry wood

 

[begreen]

OK, thanks, it's BC here (before coffee). Still, I would try resplitting the oak and check the moisture on a fresh split surface just to verify the wood is actually drying well. It should be ok, but doesn't hurt to check.

 

[michiganwinters]

Yes the smell outside isnt creosote I am very familiar as that is what most folks wood stoves smell like out here. It smells metallic. We will cool the stove off sweep and inspect. Yes we are sticklers for burning dry quality wood. A lot of this is actually over 4 yes split stacked and covered from our last house. The part that made me nervous was the smoke in the house which was burn off smoke like what u would get from breaking a stove in. So something got really hot somewhere.

 

[begreen]

We used to get this occasionally with the old Jotul 602 setup. In that case we were burning poor wood and sometime I would hear a distinct crackling rain sound from within the stove pipe and it would get hot enough to smell of baking paint and metal.

Your setup sounds fine. We have a 45 deg, double-wall offset on the same firebox and have never had an issue. Tis odd. How much wood are you burning through so far this season?

 

[3fordasho]

I have a similar set up with 2-45 degree elbows. They are a magnet for build up and a hot event will set off the build up, had it happen once.
I've installed a probe type thermometer about 18" above the stove and never let the temp exceed 700F (internal pipe temp)
and no repeats. The time it did happen I left the room for maybe 5minutes, the air and bypass were open for a reload.... thermometer was pegged at max (1000f). Never leave the stove room on start ups or reloads.

With the bypass open and lots of air the flames can be like a blow torch going up the pipe. Certain stoves are more susceptable to this than others - ie Fireview very easy because the bypass directs flames right into the pipe, my Progress Hybrid not so much because of the convoluted smoke path inside the stove.

After my event, complete with crackling sounds/hot smell and smoke in the room, I disassembled the double wall connector pipe and found no signs of damage. Now if I had left the house for hours with the stove set like that... don't know if it would still be there.

 

[begreen]

Our offset is right at the stove level and the probe thermometer is above it at 20". The flue temp will often hit 7-800F in the flue on a startup. Normal flue temp while cruising is about 100F less than stove top temp.

 

[Todd]

Leaky pipe seams can cause creosote even with dry wood. I had some problems a couple years ago and found some burnt up creosote in my system, almost looked like burnt popcorn. When I took my pipe apart I could see where the leaks were that caused the creosote. I ended up smearing furnace cement in all the pipe joints and that solved the problem.