HELP!; Wood Stove out of control

[Gridlock]

Earlier this year, on the advice of my chimney sweep, I replaced an Avalon Olympic insert with a Vermont Castings Defiant Catalytic free standing stove. The Defiant does produce a huge amount of heat, but like a spoiled child, is extremely difficult to control. This is what happened tonight, which is typical:

I started it from a cold start around 8:00pm; as usual it starts and gets going very easily. By 8:30, the top griddle temperature is about 650-700 degrees. I lower the air control and let it burn for another 30 minutes until I have a nice bed of coals; so far so good.

I then add a few splits filling the firebox about half way, let it burn for about 10 minutes, then close the damper, engaging the CAT. I turn on the Condor digital CAT gauge to monitor CAT chamber temperature. Within about 15 minutes, the CAT chamber temperature climbs from 500 to about 1300. I then lower the air control to a little more than half open. After about 10 minutes, things start to go south.

I start noticing sudden explosions in the firebox, which causes smoke to force it's way out the top loading door. The CAT chamber is reading 1700 degrees, and the stove top 600. The whole house smells like smoke. I open the air control more which after about 10 minutes, allows more flame in the firebox which helps the smoke get burned, but also increases the stove top temperature to over 700 degrees. Finally after much fiddling, both the CAT and stove top temperature drop a bit, and it runs Ok.

At other times, I've seen CAT chamber temps over 2100 degrees, and the only way to cool it down is to open the damper for a while. Although I'm not completely sure, I don't believe the wood is the problem since it starts and burns very easily and I don't hear any sizzle or see any bubbling.

What is going on here? The stove produces great heat, but is so difficult to control. Is this typical with EPA or CAT stoves, or is the Defiant just not a well designed stove?

I just paid a lot of money on this stove, but am getting so frustrated that am thinking about a replacement, maybe the new large Woodstock stove when it comes out. The other issue is that there doesn't seem to be any way to contact Vermont Castings; I tried a while searching for 'hidden' phone numbers on the internet for VC, but with no luck. How can a company like this have no contact information?

 

[begreen]

Can you tell us a bit more about the wood being burned? What species and what size splits. What is the moisture content of the wood? From the description it sounds like the wood may not be fully seasoned.

 

[North of 60]

I replaced an Avalon Olympic insert with a Vermont Castings Defiant Catalytic free standing stove.

I then add a few splits filling the firebox about half way, let it burn for about 10 minutes, then close the damper, engaging the CAT.

???

Cat or Everburn?

 

[Gridlock]

Can you tell us a bit more about the wood being burned? What species and what size splits. What is the moisture content of the wood? From the description it sounds like the wood may not be fully seasoned.

I'm not exactly sure, but was told it's mostly oak. I get my wood from a neighbor. Why do you think it may not be fully seasoned? I certainly have no trouble starting it or getting the stove hot very quickly.

 

[Gridlock]

I replaced an Avalon Olympic insert with a Vermont Castings Defiant Catalytic free standing stove.

I then add a few splits filling the firebox about half way, let it burn for about 10 minutes, then close the damper, engaging the CAT.

???

Cat or Everburn?

CAT; I thought I mentioned that several times throughout the post.

 

[North of 60]

I replaced an Avalon Olympic insert with a Vermont Castings Defiant Catalytic free standing stove.

I then add a few splits filling the firebox about half way, let it burn for about 10 minutes, then close the damper, engaging the CAT.

???

Cat or Everburn?

CAT; I thought I mentioned that several times throughout the post.

LOL. Forgive me, My brain read only
Vermont Castings Defiant (Catalytic free)
Sorry for the confusion.
I have seen the neverburn in action that also has the bypass. It had a hell of a chimney on it. 30'+. With a bed of coals and dry wood, nothing would stop the rumbling runaway until the load was gone, but if you didnt get the coal bed going then it would never take off and smoulder and back puff.
Hopefully someone can share their experience with you to help keep her under control.

Cheers

 

[madrone]

yep. not dry enough. oak takes forever to really, truly season.

 

[REF1]

Then how does the fire get going easily, and burn easily if the wood is not dry enough?

Define "explosions." Obviously you don't mean typical popping and crackling which can be heard when pockets of gases escape and ignite in a burn cycle. Combustors don't explode. I'd be curious to know what may be ON the wood your neighbor is selling you.

If the fire starts really well and you want the cat, the stove body and the flue to stay relatively close in temp rise, try starting the fire as normal, but close the air intake to half once you can see the fire is going to increase in intensity just fine. When the cat lights off and you shut your bypass try closing your intake down some before the cat has a chance to rise too quickly.

Are flames able to enter the combustor directly? That would be a design problem which could cause abnormal surges of temp rise.

 

[SolarAndWood]

What is going on here? The stove produces great heat, but is so difficult to control. Is this typical with EPA or CAT stoves, or is the Defiant just not a well designed stove?

I am a VC cat survivor. There is no comparison between the VC and the BK. It is very well controlled and amazingly predictable. I just wish I had found the forums before I went through 2 VCs believing that the problem was the wood and the way I was burning it.

 

[zzr7ky]

Wood can be dry on the outside. Oak generally gets 2 years to season properly around here. It not seasoned well It's tempermental, and i find more air is needed to keep a flame.

 

[Todd]

Sounds like you may be turning down the air to quickly causing a quick build up of gases. Try adjusting the air down further in the bypass mode so the stove pressures equalize then engage the cat.

 

[oldspark]

I do not know that much about a cat stove but if the oak is starting the fire that quick I doubt it is not dry enough, shoot from the hip replys are no help to the OP.

 

[Gridlock]

LOL. Forgive me, My brain read only
Vermont Castings Defiant (Catalytic free)
Sorry for the confusion.
I have seen the neverburn in action that also has the bypass. It had a hell of a chimney on it. 30'+. With a bed of coals and dry wood, nothing would stop the rumbling runaway until the load was gone, but if you didnt get the coal bed going then it would never take off and smoulder and back puff.
Hopefully someone can share their experience with you to help keep her under control.

Cheers

No problem; I've also heard about problems with the Everburn, but don't have that model. I started with a nice pile of very hot coals, so don't think that was the problem.

 

[Gridlock]

yep. not dry enough. oak takes forever to really, truly season.

Maybe that's true, but I certainly have absolutely no problems getting it started and burning very hot. Maybe I'll invest in a moisture meter; what percent moisture should optimally I be reading?

 

[Gridlock]

Then how does the fire get going easily, and burn easily if the wood is not dry enough?

Define "explosions." Obviously you don't mean typical popping and crackling which can be heard when pockets of gases escape and ignite in a burn cycle. Combustors don't explode. I'd be curious to know what may be ON the wood your neighbor is selling you.

If the fire starts really well and you want the cat, the stove body and the flue to stay relatively close in temp rise, try starting the fire as normal, but close the air intake to half once you can see the fire is going to increase in intensity just fine. When the cat lights off and you shut your bypass try closing your intake down some before the cat has a chance to rise too quickly.

Are flames able to enter the combustor directly? That would be a design problem which could cause abnormal surges of temp rise.

By 'explosions', it appears some smoke suddenly ignites in the main firebox causing a sudden flame and whooshing noise. It also causes smoke to get forced out of the top loading door.
Flames should not hit the combuster directly, as there is a 'throat' (piece of cast iron with holes) protecting the combustor from direct flame.

It seems that if I shut the air intake too quickly, the combuster doesn't really get going, which seems to cause excessive smoke buildup in the main firebox. I've been trying to find the optimal point to both close damper and lowering the air control. This stove just seems very finicky about getting it just right.

 

[Gridlock]

What is going on here? The stove produces great heat, but is so difficult to control. Is this typical with EPA or CAT stoves, or is the Defiant just not a well designed stove?

I am a VC cat survivor. There is no comparison between the VC and the BK. It is very well controlled and amazingly predictable. I just wish I had found the forums before I went through 2 VCs believing that the problem was the wood and the way I was burning it.

What problems did you have with your VC's? What model/year stove did you have? Were both your stoves CAT models?

 

[Gridlock]

Sounds like you may be turning down the air to quickly causing a quick build up of gases. Try adjusting the air down further in the bypass mode so the stove pressures equalize then engage the cat.

Well, this time I kept the air control at maximum until the stovetop temp was 600-650 degrees. If I kept it at that setting much longer, I would have been seeing temps over 700.

I've tried both lowering the air control quickly, and waiting for a while, but can so far not seem to get consistency.

 

[nayoung31]

http://www.chimneysweeponline.com/howhuff.htm

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

Sounds like your stove is backfiring.
The You-Tube video is showing exactly what you describe.
The Chimney Sweep website gives good insite to why it could be happening.

We had a VC Intrepid II for 18 years and toward the end it used to back fire also. I don't know if it had something to do with the CAT but it seems VC Stoves do have an issue with this.

You can look up "Wood Stove Whuffing" on the web also.

Good luck.

 

[BrotherBart]

Wood is gonna react the same way in a cat or non-cat stove. That being if you stack a load of fresh wood on top of a big hot coal bed when the stove temp is over say around four hundred degrees, all hell is gonna break loose due to the rapid outgassing of the wood. Let that puppy burn down to around three to four hundred stove top temp before reloading and see how it goes.

 

[yanksforever]

It could be a number of things BUT...I live across the river from you and the temps are quite high now for such a big fire. Drafts
aren't pulling as high either. Did you have this same problem when the temps were a lot lower?

 

[SolarAndWood]

What is going on here? The stove produces great heat, but is so difficult to control. Is this typical with EPA or CAT stoves, or is the Defiant just not a well designed stove?

I am a VC cat survivor. There is no comparison between the VC and the BK. It is very well controlled and amazingly predictable. I just wish I had found the forums before I went through 2 VCs believing that the problem was the wood and the way I was burning it.

What problems did you have with your VC's? What model/year stove did you have? Were both your stoves CAT models?

Both were DE cats, first was a 2140 and second was a 2190. Not sure of model years. The stove is our only source of heat so it is burned 24/7 7+ months. With small fires it was ok, but I could never figure out how to get consistent, reliable and safe burns without babysitting it. Watch carefully for any deterioration in the stove. It doesn't take much and the stove will go downhill fast if it isn't immediately taken care of.

 

[Gridlock]

http://www.chimneysweeponline.com/howhuff.htm

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

Sounds like your stove is backfiring.
The You-Tube video is showing exactly what you describe.
The Chimney Sweep website gives good insite to why it could be happening.

We had a VC Intrepid II for 18 years and toward the end it used to back fire also. I don't know if it had something to do with the CAT but it seems VC Stoves do have an issue with this.

You can look up "Wood Stove Whuffing" on the web also.

Good luck.

Thanks much for the links. The you-tube video looks exactly like what is happening. This is one of the responses from the video that I might try:
"The problem is caused by depriving a hot fire of air too quickly. We have the exact same problem with our VC defiant. It helps to gradually turn down the air and then close damper. We leave the air valve open 1/3 overnight."

I'm also wondering if my CAT might be clogged a bit. I removed and vacuumed it, but did notice that I couldn't see light shining through a good portion of the honeycomb, when I shined a flashlight through. Does this seem like this could be causing or exacerbating the problem? It's interesting that I believe the CAT is not lighting off as easily as it did a couple of months ago.

 

[Gridlock]

Wood is gonna react the same way in a cat or non-cat stove. That being if you stack a load of fresh wood on top of a big hot coal bed when the stove temp is over say around four hundred degrees, all hell is gonna break loose due to the rapid outgassing of the wood. Let that puppy burn down to around three to four hundred stove top temp before reloading and see how it goes.

Thanks, I'll give that a shot.

Theoretically though, wouldn't you want the firebox hotter in order to burn off excess smoke within the firebox?

 

[Gridlock]

It could be a number of things BUT...I live across the river from you and the temps are quite high now for such a big fire. Drafts
aren't pulling as high either. Did you have this same problem when the temps were a lot lower?

I have had the problem, but it does seem worse now. Despite the warmer temps, the draft still seems quite good as I have no trouble lighting it from a cold start. It's over 650 degrees stovetop in about 30 minutes.

 

[Gridlock]

Both were DE cats, first was a 2140 and second was a 2190. Not sure of model years. The stove is our only source of heat so it is burned 24/7 7+ months. With small fires it was ok, but I could never figure out how to get consistent, reliable and safe burns without babysitting it. Watch carefully for any deterioration in the stove. It doesn't take much and the stove will go downhill fast if it isn't immediately taken care of.

What do mean by deterioration in the stove? Where is there deterioration and what do you do to take care of it?

How do you find your Blaze King in comparison? How long have you had it?