Any idea's what happened to my furnace last night?

[biggenius29]

Last night was around 50 degrees, my kind of winter.

Anyway, before bed I always load up the furnace, I give it about 15 minuits or so to burn, then I turn the temp down in the house, from 70 down to 65.

Anyway, my wife got me up around 4:30 this morning and said it was cold in the house. I go downstairs to throw a piece of wood on the fire, I open the door and WOOOOFFFFFFF, fire shoots out the door at me, and shoots up my chimny. I could see the flames go past my baro. Thankfully I am paronoid about creosate, and I know my chimney was clean (I have a cleanout at the bottom which I can look up to inspect), and in my black pipe going from the stove to my SS chimney does not have any build up either from what I can see.

Any way WTF happened?

I know I needed to change my shorts

 

[aandabooks]

Sounds like gasses loaded up in the burn box and when you introduced fresh air to it, you set off a reaction and it flash burned the gasses. I know alot of people with OWBs recommend cracking open the door for a few seconds rather than just flinging it open. Long slow burns seems to cause this.

 

[dingeryote]

When you opened the door, you let oxygen into a out of balance(Too rich) atmosphere with an ignition source.

The wood gas had built up from running dampened down too far for some reason.

Stay safe!
Dingeryote

 

[biggenius29]

Sounds like gasses loaded up in the burn box and when you introduced fresh air to it, you set off a reaction and it flash burned the gasses. I know alot of people with OWBs recommend cracking open the door for a few seconds rather than just flinging it open. Long slow burns seems to cause this.

When you opened the door, you let oxygen into a out of balance(Too rich) atmosphere with an ignition source.

The wood gas had built up from running dampened down too far for some reason.

Stay safe!
Dingeryote

That is kind of what I thought. Scared me ####less regardless.

I knew something was up, because the window was black, and I could just make out the logs in there yet glowing.

When I went upstairs she asked what happened. She could hear the roar of the fire shooting up the chimney.

 

[leon]

combustion air starvation

Last night was around 50 degrees, my kind of winter.

Anyway, before bed I always load up the furnace, I give it about 15 minuits or so to burn, then I turn the temp down in the house, from 70 down to 65.

Anyway, my wife got me up around 4:30 this morning and said it was cold in the house. I go downstairs to throw a piece of wood on the fire, I open the door and WOOOOFFFFFFF, fire shoots out the door at me, and shoots up my chimny. I could see the flames go past my baro. Thankfully I am paronoid about creosate, and I know my chimney was clean (I have a cleanout at the bottom which I can look up to inspect), and in my black pipe going from the stove to my SS chimney does not have any build up either from what I can see.

Any way WTF happened?

I know I needed to change my shorts

I only have this problem when I see the smurf with the flame thrower in the ash pit because he is out of napalm

 

[mustangwagz]

Haha, when i was younger my mom did that too. we used to have an older Coal/wood stove. similar the the "wondercoal" by vogelzang. ours was called a suburban. We only burned wood in it, never played with coal. anyhow, she flung the door open, out came a puff of smoke followed by fire!! took off her bangs and eyebrows! lol. Ever since then, she has always preached about opening the bottom door for a few seconds, then open top and close the bottom one.

She no longer lives with me obviously, but she did teach us all an important lesson, always give your fire a little air when its in a controlled area at a semi slow rate!! lol.

Glad to hear you, your family and chimney are all still in one piece! becareful, and now you know! lol

 

[laynes69]

Before I go to check or load the furnace I always open the damper via thermostat. When I load, I always allow the fire to burn for around 25-30 minutes with the damper open then I close it down. I have my damper open about a 1/16th of an inch when its closed. I've never had it happen with this furnace, but with the old furnace. I was trying to burn coal and I opened the door to peek at the coal bed after 5 minutes of loading the thing and it shot blue flames out the door, the ashpan damper and up the chimney. Did it twice and I about crapped my pants. It blew ash everywhere. When its warm like that just give the furnace maybe a 1/2 load or 3 med-large splits when its mild out. You will still wake with plenty of coals.

 

[lfnh]

Thermostat didn't call for heat. Furnance sat idling for a long time building hot gas until the flash over. Possible the damper/blower actuator got stuck closed; wire came loose; thermostat malfunctioned (least likely). Something between t-stat and funance failed. Easy enough to check. Glad you're ok.

 

[Iska3]

Most likely Flash Over. I'll forget every now and then when open the door on my OWB and it will happen. For that reason, I nevere let the wife load the OWB and showed her why. It happens a lot with building and home fires. Gott'a give our firefighters a lot of credit. They put their live on the line with every fire call.

 

[mga]

When you opened the door, you let oxygen into a out of balance(Too rich) atmosphere with an ignition source.

The wood gas had built up from running dampened down too far for some reason.

Stay safe!
Dingeryote

i'd say that was the perfect anwer!!!

maybe a lesson learned from trying to shut a damper down too much?

 

[woodguy105]

Kind of like what you see in in the movie back draft...only on a much smaller scale.

 

[biggenius29]

Before I go to check or load the furnace I always open the damper via thermostat. When I load, I always allow the fire to burn for around 25-30 minutes with the damper open then I close it down. I have my damper open about a 1/16th of an inch when its closed. I've never had it happen with this furnace, but with the old furnace. I was trying to burn coal and I opened the door to peek at the coal bed after 5 minutes of loading the thing and it shot blue flames out the door, the ashpan damper and up the chimney. Did it twice and I about crapped my pants. It blew ash everywhere. When its warm like that just give the furnace maybe a 1/2 load or 3 med-large splits when its mild out. You will still wake with plenty of coals.

You know more about these Caddy's than I do Layne, but the damper has a 1" hole in it, which I think should give enough air, but I guess not.

If I would have opened the damper up would that have not been a problem?

 

[laynes69]

I don't think our hole is that large on the damper, but my model is from 2006 I believe. If your glass was black then the damper wasn't open long enough before shutting down. Maybe give it a few more minutes before closing the damper when its warmer out. Once the firebox is up to temps, it will burn fine when closed. Either that or the wood wasn't as dry as needed. I have never had any issues with ours doing that, but like said I always open the damper before going down stairs which allows for things to clear out. Otherwise crack open the door and wait a few seconds before opening it.