New OWB owners - Beware the Fireball!

[oneoldbanjo]

When I bought my OWB my dealer advised me to always check the water temperature before opening the door of my OWB. If the temperature is very near or over the upper set point - the blower/damper could have just shut off and the fire may be really hot inside the OWB with an absence of air. If you open the door and the fumes get air.....there can be a big explosion of fire out the door as the fumes ignite. My dealer also told me of a day that he took a couple out to show them the OWB he has operating on site....and as he opened the door and the flames came out the couple jumped back....and didn't come back to by a furnace.

This morning when I went out to load the furnace for the day I was reminded of this fact. My upper set point is 170 and the OWB water temp was 176, and luckily this got my attention. Last night I had loaded a bunch of very dry limbs. I leaned down a bit as I opened the door and stood behind the door - and a huge ball of flame came out of the door and completely blocked out the OWB as the air got ito the fumes inside the OWB. The flame only lasted a second and then the fire went back inside the firebox, and there was just a very hot coal bed inside with a few pieces of wood laying on the side. I raked the coals and added enough wood to last the day.

I just wanted to post this to warn any new OWB owners in case your dealer or the manual forgot to mention this to you. Be careful and always look at the temperature display before you open the door!

(I believe this subject should be a sticky)!

 

[troy3300]

I had the same thing happen to me when I first started my OWB. I was using pieces of skids to get it up to temp. quick. Well it did so I shut the door and then thought well maybe I should put a few more pieces in. I grabbed a few more pieces, walked to the boiler and opened the door (door was closed only about 10 sec.). When I opened the door the raging fire was totally black. Lucky for me I ducked down to get a better look because when I did I saw a faint glow and then everything reignited. It looked like the scences in the movie Backdraft. Flames everywhere. It was cool to watch but it I had not ducked down to look I would have been a crispy critter. Now when I open the door I stay back for about a ten count.:jawdrop:

 

[CentaurG2]

Don’t worry, the smell of singed hair does go away and eyebrows will eventually grow back. Usually happens once a season.

 

[modn]

Don’t worry, the smell of singed hair does go away and eyebrows will eventually grow back. Usually happens once a season.

Yup, my one eyebrow on the thin end is growing back nicely!! It happened when I 1st started it, door was open while I was loading it once it got going. It had lots of air, but the tips of the flames were so high it had to go somewhere, right in my face just as I lunged forward to throw a piece on. My eyelashes got some also. Learn by the mistakes and hopefully by others.

 

[John Paul Sanborn]

This can happen with any furnace, and even wood ovens. It is also how the gasification models work, they draw those fumes down into the secondary for the extra efficiency. Yeah, oversimplification, but I'm a simple man.

 

[Marc]

When that happens in a compartment fire, we call it a backdraft. Works exactly the same was as in an OWB, except it's usually someone's bedroom.

 

[oneoldbanjo]

If someone is handy with a camera....it would nice if someone posted a video of this. It would be a good training tool for new and future OWB owners. You can very easily recreate this scenario......just open the door a few seconds after the blower shuts off.

 

[November Wolf]

Thanks for the tip.

I read on another forum about a guy with a CB e2300 gasification OWB and when he opened the door it exploded and blew the sheet metal off. The guy did'nt get hurt but I bet it scared the hell out of him.

 

[Techstuf]

Of course, one can also practice the habit of shielding one's self behind the door as it is opened. Or, if possible, open the ash door first to invigorate the draft.


TS

 

[csj11]

One a little bit at first!

I have asked the wife and kids to open the door about an inch or 2 for a few seconds to let that happen in a more controlled way.

Scott

 

[oneoldbanjo]

MY OWB does not have an ash door. The blower and damper are located in the door - and when they shut off there is no way to allow air into the firebox without opening the door. When it comes time to load.....you just need to be aware what is going on behind the door....before you open it.

 

[cleanburn]

Thanks for the tip.

I read on another forum about a guy with a CB e2300 gasification OWB and when he opened the door it exploded and blew the sheet metal off. The guy did'nt get hurt but I bet it scared the hell out of him.

This is actually a little different then what the original poster posted. What happened in the Eclassic is more typical of a downdraft and since these guys have been putting paperclips on their "flippers" on those stoves it will happen if the conditions are right, wind, etc....his sheet metal blew off the back of his stove where his airbox is located, not through his front door.

The flashback what the original poster is talking about is through the front door of the stove. My Heatmor has a thing called a Anti-Rollout device that opens and lets air into the firebox before you open the firebox door, that helps to stop flashback and also my heatmor has a latch on the firebox door so you really can't open it quick enough to get a flashback in your face....

Safety first

 

[Techstuf]

Sounds like 'Heatmor' has a good insurance/engineering liaison.


TS

 

[KsWoodsMan]

When I bought my OWB my dealer advised me to always check the water temperature before opening the door of my OWB. If the temperature is very near or over the upper set point - the blower/damper could have just shut off and the fire may be really hot inside the OWB with an absence of air. If you open the door and the fumes get air.....there can be a big explosion of fire out the door as the fumes ignite. My dealer also told me of a day that he took a couple out to show them the OWB he has operating on site....and as he opened the door and the flames came out the couple jumped back....and didn't come back to by a furnace.

This morning when I went out to load the furnace for the day I was reminded of this fact. My upper set point is 170 and the OWB water temp was 176, and luckily this got my attention. Last night I had loaded a bunch of very dry limbs. I leaned down a bit as I opened the door and stood behind the door - and a huge ball of flame came out of the door and completely blocked out the OWB as the air got ito the fumes inside the OWB. The flame only lasted a second and then the fire went back inside the firebox, and there was just a very hot coal bed inside with a few pieces of wood laying on the side. I raked the coals and added enough wood to last the day.

I just wanted to post this to warn any new OWB owners in case your dealer or the manual forgot to mention this to you. Be careful and always look at the temperature display before you open the door!

(I believe this subject should be a sticky)!

Built in feature ?

We all like a little excitement . What better way to get the blood going ?

Good point to bring up though. Open slowly so as not to disturb the sleeping dragon.

 

[Mister Twister]

Yes that can happen with any wood burning device if the conditions are right. I did it once also now I just open the door about an inch let some air in then finish opening it. I guess you could you the analogy test the water first.

 

[cfabe]

I recently heard by word of mouth that a guy in the next town over (Breckenridge, MI) was killed by this phenomenon a few weeks ago. What I heard was the boiler flashed back and he sustained burns over 50% of his body which proved fatal. Don't know if his clothes caught fire or what happened. Heard it was an older gentleman. Did not see any news coverage of the incident, has anyone hear heard about it? I know we got some other Michigan guys here.

Personally, I have not had this happen yet. But I do generally open the door slowly as a habit from when I used a wood stove that would smoke if opened quickly.

 

[Slick]

I also open slowly just because of the smoke that always rolls out..but I'll add this to the list also....I've had it roaring while loading before...like really roaring but I just shut the door for a few seconds and it calms down.

 

[November Wolf]

This is a good thread. I am glad this was brought to my attention that something like this could happen. I know I will be more carefull loading now.
+ rep from me.

 

[Geez]

My OWB has a hook on the latch, so when I unlock the door the hooks engage. This then only allows the door to open a couple inches and can't blow open. After you're sure it is safe you can open it up all the way. Saved many an eyebrow for me.

 

[mtfallsmikey]

Yes Virginia....I've singed my hair too!