Back 1/3 of the stove not burning

[Michbrog23]

So I’ve been burning in my Osburn 950 for almost 3 weeks, and still trying to get it figured out. Have a 28-30 ft interior chimney with a stainless insulated liner, and it burns great in the front 2/3rds of the stove, but it’s struggling to fully catch and get an efficient burn in the back 3rd of the stove. I have no issue getting the stove to temp or with reloads, and usually have the air control all the way down within 15 minutes of a re-load. Everything is fine until about an hour and a half in, and the back 1/3 starts to smoulder and I have to adjust the wood and coals. Any help would be much appreciated. I’ve been testing the wood and haven’t been burning anything above 16-17%, mostly 12-15

 

[EbS-P]

My guess is that with that tall of chimney you are needing to turn air all the way down so when the burn slows down and the chimney cools down a bit you don’t have enough draft. Was the liner insulated? You could install a damper in the appliance adapter.

 

[Michbrog23]

The liner is a 316 hybrid that’s insulated, and also had to use an offset box, given the space of the install. So the liner is struggling to stay hot enough for a good draft you think? When I adjust the wood and coals to the front they do great

 

[EbS-P]

The liner is a 316 hybrid that’s insulated, and also had to use an offset box, given the space of the install. So the liner is struggling to stay hot enough for a good draft you think? When I adjust the wood and coals to the front they do great

Ok offset box and insulation change things. Are you measuring any temps?

 

[Michbrog23]

Measuring the stove top and have one of top of the offset box, although not sure if that’s doing much good. I’m guessing the only way to truly gauge the flue temp would be to put a probe thermometer in the liner?

 

[Michbrog23]

It seems like the issue starts once I close the door on a re-load. It takes off fine with the door slightly cracked, but once I shut the door, even with the air control all the way open, seems like the flame and burn is uneven and only in the first half, 2/3rds of the stove

 

[Enplater]

Do you take a freshly split piece of wood and test it in the middle of the freshly split part? I test with the grain, which I believe is correct.
Judging by the last thing you said it sounds like not fully seasoned wood. To test for this people will sometimes buy some kiln dried wood or sawdust bricks and try that, see it acts normal.

 

[Michbrog23]

Do you take a freshly split piece of wood and test it in the middle of the freshly split part? I test with the grain, which I believe is correct.
Judging by the last thing you said it sounds like not fully seasoned wood. To test for this people will sometimes buy some kiln dried wood or sawdust bricks and try that, see it acts normal.

I’ve been testing fresh splits, and getting those numbers, which makes it that much more confusing. I’ve thought about trying another moisture meter, just to double check. Definitely like the idea of trying some kiln dried stuff or pine pallets

 

[EbS-P]

When the stove is burning well what are the stove top temps?

Offset boxes are a means of last resort. They restrict the draft. There was no to connect the stove with an angled appliance adapter?

From what you have said it sounds like insufficient draft issue. But with more than double the minimum spec height it should be needing a damper.

Check all the flue connections for leaks and make sure the nothing is blocked. Take off the offset clean out and shine a flashlight in. If this didn’t start burning this way 3 weeks ago check your chimney cap for blockage.

 

[Michbrog23]

When the stove is burning well what are the stove top temps?

Offset boxes are a means of last resort. They restrict the draft. There was no to connect the stove with an angled appliance adapter?

From what you have said it sounds like insufficient draft issue. But with more than double the minimum spec height it should be needing a damper.

Check all the flue connections for leaks and make sure the nothing is blocked. Take off the offset clean out and shine a flashlight in. If this didn’t start burning this way 3 weeks ago check your chimney cap for blockage.

The stove cruises to 700 with no problem at all, and we have to keep the air closed to keep it their as well.

I think the issue is with the offset box as well, and it actually got a split in it on the front after about a week. I had a different chimney sweep come out and look at it, and he put some screws in it, and said it shouldn’t be an issue, but sure seems like it’s causing problems

 

[Enplater]

sounds doubtful it’s a wood problem. I don’t even know what an offset box is so hopefully someone else can help solve the problem. Good luck

 

[EbS-P]

Did you post a picture in another thread? My guess and it’s just that, your overdraft got the offset too hot it failed and is now leaking sucking cold air up the chimney and reducing draft in the stove. My recommendation is to see if you can use angled appliance adapters and a damper and get rid of the box.

Post a picture of you can. Also you can leak test the the box to see if it’s sucking smoke or flame from a candle into a joint or seam.

The stove cruises to 700 with no problem at all, and we have to keep the air closed to keep it there as well.

I think the issue is with the offset box as well, and it actually got a split in it on the front after about a week. I had a different chimney sweep come out and look at it, and he put some screws in it, and said it shouldn’t be an issue, but sure seems like it’s causing problems

 

[begreen]

How is the stove being loaded? E/W, N/S, or both (Lincoln log style)?

 

[Michbrog23]

Did you post a picture in another thread? My guess and it’s just that, your overdraft got the offset too hot it failed and is now leaking sucking cold air up the chimney and reducing draft in the stove. My recommendation is to see if you can use angled appliance adapters and a damper and get rid of the box.

Post a picture of you can. Also you can leak test the the box to see if it’s sucking smoke or flame from a candle into a joint or seam.

Thank you for the replies and input, I think you’ve probably nailed it. I think my wife had gotten the stove too hot while I was at work, and this caused the box to fail. I took off the clean out plate and the box is split in the back as well. I’ve posted some pics, I’m assuming that’s the start of creosote build up as well in the offset box?

 

[DBoon]

I had a similar problem in my Lopi Answer (small stove) with E-W loading when my wood wasn't optimally dry.

If you are loading E-W, try putting some pieces of kindling that are 1/4" thick or so both underneath the back stack and behind the back stack so that airflow can get around the back stack and it can combust better.

 

[Michbrog23]

So i replaced the offset box, and can get to the stove to 700 within about a half hour and firebox is doing great, but an hour in and I’m still seeing white smoke out of the liner, and after about an hour and a half of burning, it seems like the rear of the stove still smoulders and I have to rearrange the wood. I fresh spit my latest load and had nothing above 15% in the stove.
I’m at a loss

 

[Michbrog23]

As crazy as it seems, I feel like it performed better with a small split in the back of the offset box. The smoke out the liner very lasted more than 25-30 minutes after a reload

 

[begreen]

If the "smoke" is white and dissapates within 10 seconds it may be steam.

 

[Michbrog23]

If the "smoke" is white and dissapates within 10 seconds it may be steam.

Thought that may be possible after further research, and the fact it’s about 13 degrees here. The e wood stalling at the back of the stove seems to be a real issue though, it’s almost like it never really catches. I guess I’m still trying to figure out the secondary burn concept as well

 

[Michbrog23]

I’m having to open the air back up and pull the wood to the front of the fire box basically every load at the 1.5-2hr mark to keep it from smoldering and causing more smoke up the liner

 

[begreen]

Thought that may be possible after further research, and the fact it’s about 13 degrees here. The e wood stalling at the back of the stove seems to be a real issue though, it’s almost like it never really catches. I guess I’m still trying to figure out the secondary burn concept as well

This is not all that uncommon with an E/W load. The air gets blocked by the front wood. You could try putting in a pair of 2" thick sleeper sticks first, about 8" apart, and then load the splits on top of them. That will permit air to get to the rear wood faster on startup.

 

[Michbrog23]

This is not all that uncommon with an E/W load. The air gets blocked by the front wood. You could try putting in a pair of 2" thick sleeper sticks first, about 8" apart, and then load the splits on top of them. That will permit air to get to the rear wood faster on startup.

I’m doing N/S loads, which makes me more confused. I’ve tried to place to smaller kindling on top of the bottom splits, but still seems to happen. I’m afraid it’s a drafting issue that may be tough to resolve, but this is my first month with the stove, so I’m open to any suggestions

 

[begreen]

You may not be doing anything wrong. Our stove tends to burn front to back also. Try opening up the air more toward the later stage of the burn. If you want more heat while burning up that rear wood, pull it forward and add a couple thin splits on top. Pine or fir work good for this.

 

[Michbrog23]

You may not be doing anything wrong. Our stove tends to burn front to back also. Try opening up the air more toward the later stage of the burn. If you want more heat while burning up that rear wood, pull it forward and add a couple thin splits on top. Pine or fir work good for this.

Thank you, I’ll certainly give it a try!