House fire today

[dispatcher101]

Had a structure fire today at work. It was due to a pellet stove. The temps were in the 20's with winds steady at 40 gusting to 50 mph. It was around 4am and winds had been ripping for 2-3 hours prior. The family didn't have a thermo on the stove. They woke up to heavy smoke in the house. I guess the guy tried shoveling out some of the pellets to cool the stove down, but was unsuccessful. I am unfamiliar with how the pellet stove works.

Can extreme winds case the draft to be so strong as to overfire the stove to that degree in both a pellet or woodburner? I don't know what his setup was like.

Luckily no one was hurt, and the house was not a total loss.

 

[Dakotas Dad]

They didn't have a "thermo"? thermometer, or thermostat? one I could run without.. one not so much.

All the pellet stoves I looked at had an auger that would only feed pellets from the hopper at a certain rate determined by the thermostat. I didn't *think* you could over fire one.. when we looked at them our thought was they were "wood heat" for people that didn't want any of the work of wood heat. almost a "set it and forget it" stove. We don't have a single pellet tree so we didn't follow up on it..

 

[dispatcher101]

That was my thought as well. But something must have gone wrong. He said that the fire was "WAY TOO HOT". His remedy was to try to shovel out some of the pellets. I don't know if the very high winds had something to do with it as well? I asked the wife if they had a thermometer on the stove and she said they didn't?

 

[Shari]

We don't have a single pellet tree so we didn't follow up on it..

Now that thar statement is funny!

Shari

 

[dispatcher101]

Also posted this on hearth, but thought this forum may be more appropriate.

Had a structure fire today at work. It was due to a pellet stove. The temps were in the 20’s with winds steady at 40 gusting to 50 mph. It was around 4am and winds had been ripping for 2-3 hours prior. The family didn’t have a thermometer on the stove. They woke up to heavy smoke in the house. I guess the guy tried shoveling out some of the pellets to cool the stove down, but was unsuccessful. I am unfamiliar with how the pellet stove works.

Can extreme winds case the draft to be so strong as to overfire the stove to that degree in both a pellet or woodburner? I don’t know what his setup was like.

Luckily no one was hurt, and the house was not a total loss.

 

[Snowy Rivers]

In order to really understand what happened, we would need to know a lot of particulars about the stove and the installation.

Pellet stoves have several safeties that should have prevented an overtemp condition.

As far as "overdrafting" the stovve is still only going to feed just so much fuel into the burn pot, no matter what the draft.

Now if this was a hopper fire, thats a horse of a different color.

Over fires, hopper fires and intake air overtemps are all pretty well guarded against.

The stove may have been in need of service or ????

Without actually seeing what happened its tough to add anything more to this.

Any further info would be useful.


Snowy

 

[dispatcher101]

I don't know any of the particulars about the stove or it's set up. I was busy gathering other important info from the caller. He told me he tried "shoveling out some of the pellets". So maybe it was a "hopper fire as you would call it. I don't know under what circumstances they can occur, but I would guess that the extreme winds and blowing snow contributed in some way.

 

[SmokeyTheBear]

Can you get more particulars?

 

[dispatcher101]

I might try tonight. Kind of a touchy subject to follow up on. But I will try...."Sorry about your house catching on fire..." If I approach it from an educational standpoint I think they might be receptive.

 

[rottiman]

Not knowing anything as to how is was set up, I can only hazard a guess as to what happened. It sounds like his combustion fan might have been dirty and under producing the required amount of air, but enough to not shut the stove down. With the heavy winds, it might have over powered the fan and put enough pressure, in reverse, to send flames up the hopper shoot and start the pellet supply in the hopper to burning. Thus the whole stove was over-heating. Hopper fires in pellet stoves are rare but have severe ramifications. Only a guess on my part............... I burned wood for a whole lota years, but decided to try the pellet thing. One winter of that has now convinced me to go back to wood. Wood may be dirtier, but it sure is much nicer heat and a whole lot less daily upkeep.
My .02$$$$$$ on the subject.

 

[Snowy Rivers]

Blowing snow/wind should not have caused any real issues but without other info its impossible to tell.

Make and model of the stove
Direct vent or tall chimney type vent
Was the fire in the hopper?


Guessing is not a good idea, but my first thoughts are that possibly the exhaust fan failed due to ????????? and the fire burned back up into the hopper and resulted in the fire spreading into the home

See if you can get us some particulars and maybe we can come to some reasonable conclusions

Poor maintenance is a big contributor to issues with any heating appliance the burns fuel, be it oil or a solid fuel.

A pellet stove although very simple, still needs regular service to be efficient and safe.

There certainly exists the possibility that the stove was in poor condition.

Another issue that can cause hopper fires is a badly eroded "Fire back" insulator

If the fire back is in poor condition and the stove is being operated at a very high setting the radiated heat through the back of the fire box could "Possibly" cause the pellets in the hopper to ignite.


This is a pretty narrow possibility but could occur.


Too many variables without good info.


Snowy

 

[SmokeyTheBear]

OK, I understand on the touchy part.

Here is what can cause issues:

If any of the safeties have been bypassed (sometimes done to rule out problems) and were not restored to their original installed state.

A defective safety. There are several on a pellet stove.

One is a vacuum switch that shuts off the fuel feed if a loss of pressure difference occurs, if this switch fails such as to indicate there is a vacuum present when there isn't the stove will continue to feed fuel and if other conditions are in existence cause smoke to be dumped into the house if there is an air path that allows it.

If the lack of vacuum is not indicated and it actually exists because of a combustion fan failure or extreme back pressure (due to high winds directly entering the vent) it is possible for a temperature build up to take place inside the stove shell over time, because the hot exhaust can't exit through the venting. It might be possible that this hot exhaust was trying to exit through the hopper and started the pellets smoldering.

There is also an over temperature safety on the heat exchanger, if the hi temp limit is exceeded the fuel feed stops (on some stoves it is a manual reset device, on others it is an automatic reset device. It is possible if this safety failed for the heat exchanger to build up temperature over time and start the pellets in the hopper smoldering.

Some hoppers are gasketed and thereby air sealed provided the gasket is intact and the hopper door closed and latched. Even if the pellets get above ignition temperature there is a severe lack of air so combustion is highly unlikely unless the hopper is opened or there is another air path for the hopper.

There are also thermal protections on some of the blowers that shut them off if the motors go over temperature. The one on the convection fan is frequently hit if the bearings fail, they lose lubricant, or are located too close to the firebox. This normally causes the hi temp limit to trigger. It might not on the lowest firing rates of a stove because normal air movement through the heat exchanger may keep it from happening.

The thermal protection on the combustion fan will normally get detected by the vacuum switch indicating lack of a pressure difference, a frequent cause of this one triggering is a failed bearing or back pressure in the exhaust .

In some cases it might be possible for a serious condition to be indicated by the safeties but not acted upon by the control system, this would depend upon how everything is tied together.

Those are just a few ways for things to happen.

There is also a possibility of certain auger system issues or even creosote buildup getting into the act.

 

[Czech]

Are you sure they weren't burning candles in the house?

 

[begreen]

Sounds like either user error or something was jerry-rigged or a combo of both. On really cold days, I've has a pellet stove running continuously for >12hrs. without incident. This would be the same as if the thermostat terminals were bridged so that it was always on.

I'm guessing that the cause could be that the exhaust system was using wrong pipe and/or too close to combustibles. Or perhaps the hi-temp safety switches were jumpered (no thermostat?) and the stove overheated due to lack of cleaning?

 

[vvvv]

Not to be cynical, but is insurance paying?

 

[hossthehermit]

We don't have a single pellet tree so we didn't follow up on it..

Now that thar statement is funny!

Shari

Not to be rude, but there ain't nothing funny about a house fire.
That aside, my bet is the stove was cleaned out that day, and ashes improperly disposed of.

 

[Lousyweather]

not that it could ever be the homeowner's fault, but my money is on improper maintenance

 

[Dakotas Dad]

We don't have a single pellet tree so we didn't follow up on it..

Now that thar statement is funny!

Shari

Not to be rude, but there ain't nothing funny about a house fire.
That aside, my bet is the stove was cleaned out that day, and ashes improperly disposed of.

not to be rude back, but NO ONE made fun of the house fire, it was simply a statement concerning WHY a pellet stove was not investigated further in my household.

 

[mascoma]

I'm thinking that the wind may have contributed to a malfunction that caused smoke to enter the house and would have been harmless until the home owner tried to shovel out some of the burning pellets, dropped them on the floor and the house caught fire.

 

[SmokeyTheBear]

I'm thinking that the wind may have contributed to a malfunction that caused smoke to enter the house and would have been harmless until the home owner tried to shovel out some of the burning pellets, dropped them on the floor and the house caught fire.

I was thinking that after I read the posts that were in the Hearth Room. We still don't know what burning pellets were being shoveled out.

Those in the hopper or those in the fire pot.

It isn't a good idea to open the hopper cover and start bailing burning things, better off turning the stove off and if it doesn't answer the off switch pulling the plug or dumping the circuit breaker.

If one feels they have to play firefighter they are best off with a few CO2 extinguishers and discharging those into the air intake .... etc ....

The long and short of it is we just don't have enough information to go on.

 

[SmokeyTheBear]

Are you sure they weren't burning candles in the house?

That's the question that was asked of another party by some firemen in New Hampshire when there was a big hole in the roof and metal slag from a direct lighting strike.

 

[Dave_1]

Are you sure they weren't burning candles in the house?

That's the question that was asked of another party by some firemen in New Hampshire when there was a big hole in the roof and metal slag from a direct lighting strike.

Yup, when those industrial candles lite off they really lite off. ;-)

Well, there was one guy on that link I would like to ride this candle. :lol:

Try it again.

http://www.youtube.com/watch?v=jKVU...37AA77623&playnext=1&playnext_from=PL&index=5

 

[SmokeyTheBear]

Are you sure they weren't burning candles in the house?

That's the question that was asked of another party by some firemen in New Hampshire when there was a big hole in the roof and metal slag from a direct lighting strike.

Yup, when those industrial candles lite off they really lite off. ;-)

http://www.youtube.com/watch?v=jKVUHhHKe1

That link doesn't workie to well.

 

[begreen]

The fixed link does work. Boy, what a nightmare. It must have felt like the end of the world to folks close by. What a disaster!

 

[Martin Strand III]

Sorry to learn of this loss. Realistically, home destruction by accessory heater fires do happen including wood, pellet and coal stoves. We've had several in the past few months around these parts.

Sadly and statistically, most fire control "problems" are the result of operator error; neglect, inexperience, inattention and, worse, arrogance or just plain stupidity.

Aye,
Marty
Grandma used to say, "Play with fire and you will get burned."