Wood Heater Experts-I Have a Question

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Country Lady

Member
Hearth Supporter
Jan 20, 2007
51
I was up during the night last night and added a couple pieces of firewood to our wood stove (fireplace insert). I had the damper opened all the way for a few minutes to give it a chance to catch up, then closed the damper down some then went back to sleep. Well we were awakened with a noise. We found the facing that covers up the rest of the fireplace, whatever that's called, blown out and some insulation out also. The little pot on top holding water had been knocked off and water was everywhere. My husband checked it out this morning and everything seemed to be ok. It's going now and is fine. So, "Experts", what do you think of this?
 
No expert, but sounds like you may have dampered it down to quickly and had a build up of gases that ignited. Not sure why the facing would have come off. Must have been one hell of an explosion!!
 
By facing do you mean the trim around the stove to the opening? How far does your stove pipe go up in the chimney? Is there a block off plate?
 
Country,

We don't know about your installation, but the assumption is that you do not have your unit piped properly - way up past the damper a couple feet....and then a tight sheet metal block off plate at the damper area.

If this is true, then what happened was that some smoke (which is made up of conbustible gases) built up in the fireplace chamber and then was ignited - what we call a wood gas explosion...and that blew the thing apart.

Time to install it correctly. We can help if you describe and give model or post pics of installation as it is.
 
Michael6268 said:
No expert, but sounds like you may have dampered it down to quickly and had a build up of gases that ignited. Not sure why the facing would have come off. Must have been one hell of an explosion!!

We're thinking this is the case. The stove was installed by the fireplace store where we purchased the stove March 2006, so we're assuming he knew what he was doing. He also cleaned the chimney at that time. Thanks for all your thoughts.
 
Wow, that is a newer stove and we would think it was installed correctly. Do you see a stainless steel flexible tube going up from the rear of the unit and then through the damper?

Do you remember what the installation charge was? that might help determine what exactly was done.
 
look outside at the top of the chimmney, did they put a little cap up there? if not chances are you do not have a liner..
Cleaning a chimney is great, not lining it is a NO NO...
And there probably is not a block off plate as they probably would have seen this hanging down after the surround blew off.
****EDIT****
I Reread.... The block off plate (or insufficient one) was blown out....... What kind of insulation did you find in there? Was it regular fiberglass?
 
Hopefully shes still reading or I think the next time she gets a build up she might blow the front of her house out.
 
Webmaster said:
Wow, that is a newer stove and we would think it was installed correctly. Do you see a stainless steel flexible tube going up from the rear of the unit and then through the damper?

Do you remember what the installation charge was? that might help determine what exactly was done.

Yes there is a stainless steel tube going up from the rear of the unit. Since we had the chimney cleaned at the same time the fireplace insert was installed, I can't remember exactly how much each cost since I wrote a check for all, but it was somewhere around $250. The stove seems to be working fine now. Our house is five years old and the stainless steel liner was installed at the time the house was built.
 
Do you know how far up the liner gos up? is there a cap on the top? Is there a block off plate
( anymore ) where the liner enters the chimney? Did you repair the surround ( the face plate )?All of these things put your safety at risk. Another flashback in lesser conditions could put your house and you at risk.
 
nshif said:
Do you know how far up the liner gos up? is there a cap on the top? Is there a block off plate
( anymore ) where the liner enters the chimney? Did you repair the surround ( the face plate )?All of these things put your safety at risk. Another flashback in lesser conditions could put your house and you at risk.

Yes, there is a cap on top. I'm not sure about a block off plate. Yes, we got the face plate back in place. Thanks for all the replies.
 
Country Lady said:
Webmaster said:
Wow, that is a newer stove and we would think it was installed correctly. Do you see a stainless steel flexible tube going up from the rear of the unit and then through the damper?

Do you remember what the installation charge was? that might help determine what exactly was done.

Yes there is a stainless steel tube going up from the rear of the unit. Since we had the chimney cleaned at the same time the fireplace insert was installed, I can't remember exactly how much each cost since I wrote a check for all, but it was somewhere around $250. The stove seems to be working fine now. Our house is five years old and the stainless steel liner was installed at the time the house was built.
I'm a bit confused here The home when built had an fireplace..... And when it was built they put a stainless liner in it.. Then a couple of years later a insert was installed and a new liner was not put in because there was one already there???????????????????????????
That makes no sense to me.... Do you know this for fact or is this what the installer said to you.......
Could it possibly be that you have a masonry chimney with a stainless liner rather than clay flue tiles? Thus you would have your stove pipe dumping into a
"stainless lined chimney" though this chimney is lined the stove pipe is not lined properly.....
Just a possibility
 
Maybe Im wrong but I dont think you fixed the problem. It could very well happen again. But if your happy ok. I suspect we will see you back here before too long, Am I offbase here guys or is this a potently dangerous situation?
 
nshif said:
Maybe Im wrong but I dont think you fixed the problem. It could very well happen again. But if your happy ok. I suspect we will see you back here before too long, Am I offbase here guys or is this a potently dangerous situation?
Don't know but I'm sure I'm on a bunch of peoples ignore lists :cheese: ,and they only see what they want but It just sounds like an unsafe situation to me..... If the surround blows off the stove it didn't come from a lined chimney it came down the chimney and out through the easiest thing to move.... the surround... IMHO...
Just my .005 cent
 
This is Country Ladies Husband. When we had the house built, we had the stainless steel liner rather than the clay tile put in the chimney. We purchased the stove from a very reputable dealer and feel the installation was done correctly. My wife also posted this same question on another board. Someone suggested that she closed the damper to much after charring the wood, using up all the oxygen too quickly, causing the stove to gulp.
 
Country Lady said:
This is Country Ladies Husband. When we had the house built, we had the stainless steel liner rather than the clay tile put in the chimney. We purchased the stove from a very reputable dealer and feel the installation was done correctly. My wife also posted this same question on another board. Someone suggested that she closed the damper to much after charring the wood, using up all the oxygen too quickly, causing the stove to gulp.
So are you saying that the stove does not have a pipe say 6" DIA from the back of the stove running through the chimney all the way to the top?

Sorry where are my manners WELCOME to the forum..

It does not sound like a proper lining.
 
The following is an opinion from a poster on another board.

Sounds like it "backfired" Sometimes flammable gasses build up, and with the right mix of oxygen they "flash" and ignite, causing a burst of pressure.

"When you have a rip-roaring woodstove fire going, your chimney is charged with rising superheated exhaust gases, so the air flow through the firebox is considerable. If you cut down the supply of air too abruptly, the fire instantly consumes the available oxygen, creating a powerful vacuum inside the stove. If strong enough, this vacuum can reverse the flow inside the chimney, pulling a "gulp" of air back down the flue into the firebox. When this pocket of air hits the fire, a mini-explosion occurs, and the resulting sudden extreme pressurization inside the firebox forces smoke out through the draft control, door gasketing and other tiny openings that exist in even the most "airtight" woodstoves. This brief period of pressurization is followed immediately by extreme depressurization (because the explosion consumes all the available oxygen in the firebox), and another gulp of air can be pulled down the chimney, causing the process to repeat. We call this "whuffing", due to the accompanying sound of muffled explosions. In extreme cases, these repeated explosions can cause the stove to actually dance around on the hearth!"
 
Country Lady said:
My wife also posted this same question on another board. Someone suggested that she closed the damper to much after charring the wood, using up all the oxygen too quickly, causing the stove to gulp.
You are now here on the HEARTH and these guys know alot about woodburning and I know alot about nothing,,,
Not that it matters because it sounds like the vent setup what kind of stove do you have??????/
 
Could be something is broke, has a hole in it or has come apart. I would call the shop for a chimney sweep to come out for a cleaning and an inspection before I would use it again.
 
at $250 you have a direct connect into your existing flue

would you check and report back the size of your existing liner? and the size of the original fireplace opening

Before jumping to conclusions I need that info.

I asume you are burning dry wood? When is the last time you chimney condition was checked ?

Here is what I am thinking, cresote built up in the chimney and fell down onto the damper plate and on the damper area. It could accululated enough that is was resting against the pipe
It is possible that it ignited. I would love to do a through inspection of your situation to narrow down the cause and any future risk if any

Couple final questions, was the damper plate removed? Does the pipe from the stove start out round and ovalized when it enters the damper area and confirm a metal block off at the base of the damper area. Is this chimney located on an exterior wall?

GVA I have yet to use the ignore function so you are not on my list for that matter no one is
 
elkimmeg said:
at $250 you have a direct connect into your existing flue

would check and report back this the size of your existing liner? and the size of the original fireplace opening

Before jumping to conclusions I need that info.

I asume you are burning dry wood? When is the last time you chimney condition was checked ?

Here is what I am thinking cresote built up in the chimney and fell down onto the damper plate and on the damper area It could accululated enough that is was resting against the pipe
It is possible that it ignited. I would love to do a through inspection of your situation to narrow down the cause and any future risk if any

couple final questions was the damper plate removed? does the pipe from the stove start out round and ovalized when it enters the damper area and confirm a metal block off at the base of the damper area. Is this chimney located on an exterior wall?

GVA I have yet to use the ignore function so you are not on my list for that matter no one is

I can answer part of your questions. Yes, we do burn dry hardwood, no pine. The damper plate was removed when the insert was installed. It starts out round and is ovalized when it enters the damper area. I am not sure about a metal block off at the base of the damper area. It is located on an interior wall.
 
That's what it sounds like. I added a few new logs to my fire the other day, then closed the air off too soon. There was a mighty 'kerwhomph" when the wood gases ignited. It blew smoke out of every crevice in the stove. Can you provide a few more details about the stove make and model and maybe a picture of the installation?
 
im with elk, to blow the surround off , the explosion had to be able to expand outside of the pipe, if unit is lined all the way up it stays inside the flue pipe, unless the stove "jumped" and shook off the plate and the water container on top, the expansion had to have been released outside of the flue pipe , that means direct connect , not a full liner
 
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