Woodstock Absolute operation question

[kearlymad]

My husband and I bought a Woodstock absolute hybrid stove this past fall and really like it but are having a couple of issues. Background: we've heated with wood 20 years (1995 VC Resolute, 2011 Buck Stove). The Vermont Castings was in this house with the same chimney (brick chimney lined with insulated stainless pipe) set up and had no draft problems but this stove wants to smoke at start up so guessing the draft is not working as well somehow. We leave the door cracked an inch at startup and this works.

- We are having problems with backpuffing/mini explosions when we have hot wood (red oak, locust, or hickory) loaded and the stove set on around 2.5. Woodstock suggested our wood is too dry - it is 11-15% per our moisture meter. We can open the draft a couple of dots when it backpuffs and that stops it but makes us too nervous to leave the fire unattended the first couple of hours.
- Can someone explain or show a picture of how they fully load the stove? We don't have good coals left in the morning (after 10-12 hours) although the stove is still warm from the soapstone. I suspect we are not loading it full enough. Generally load a 2 small, 2 medium and 2 larger splits on existing coals.

Other than these 2 issues we love the stove - including the looks which I know some don't like. And love that it stays warmer much longer than our other stoves. We live in the NC mtns in a small old house which we have insulated fairly well. We build a small fire in the late afternoon, let coals build up and do our main load early evening. In the morning the house is usually still above 65 and the stove sides often warm but no real coals.

Thanks!

 

[Slocum]

My husband and I bought a Woodstock absolute hybrid stove this past fall and really like it but are having a couple of issues. Background: we've heated with wood 20 years (1995 VC Resolute, 2011 Buck Stove). The Vermont Castings was in this house with the same chimney (brick chimney lined with insulated stainless pipe) set up and had no draft problems but this stove wants to smoke at start up so guessing the draft is not working as well somehow. We leave the door cracked an inch at startup and this works.

- We are having problems with backpuffing/mini explosions when we have hot wood (red oak, locust, or hickory) loaded and the stove set on around 2.5. Woodstock suggested our wood is too dry - it is 11-15% per our moisture meter. We can open the draft a couple of dots when it backpuffs and that stops it but makes us too nervous to leave the fire unattended the first couple of hours.
- Can someone explain or show a picture of how they fully load the stove? We don't have good coals left in the morning (after 10-12 hours) although the stove is still warm from the soapstone. I suspect we are not loading it full enough. Generally load a 2 small, 2 medium and 2 larger splits on existing coals.

Other than these 2 issues we love the stove - including the looks which I know some don't like. And love that it stays warmer much longer than our other stoves. We live in the NC mtns in a small old house which we have insulated fairly well. We build a small fire in the late afternoon, let coals build up and do our main load early evening. In the morning the house is usually still above 65 and the stove sides often warm but no real coals.

Thanks!

I don’t have a AS but we have a IS. Is there a wire mesh or spark arrester on the rain cap of your chimney? Just wondering if there could be a restriction in chimney. I have only experienced back puffing at start up. I don’t understand how your wood can be to dry. Our wood is in same moisture % as yours and have to many coals left if anything. The smoke coming out of door when reloading is frustrating but I have found if I crack the outside door which is close to our stove it help considerably on the smoke. Also I have my wood close and load fast. I will see if I can find a pic of my stove loaded, if not I’ll take one when I load this morning.


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[Woody Stover]

No, I don't think your wood can be too dry in most US locales. Maybe in the desert southwest you could get it too dry...
What do you mean, "wants to smoke at startup?" It won't flame with the door closed when trying to start a new load? The stove's not completely cold, right? What is the air setting, 2.5 out of how many? There's no flame in the box at this setting, it's a cat-only burn?
How tall is the chimney? I'd guess it's decent height if it's masonry, though. When was the liner last swept? Much creosote when that was done?
I don't have an AS, although I'm considering one..
Can you more fully describe your startup procedure? You load some wood on coals, have the door cracked until it flames up...then what, close the door and it will flame OK? How long do you burn in the load? You don't hear any hissing or see water on the ends of the splits, right? I know you said the meter shows it is dry.. After an hour or two, the back-puffs are over?

 

[John B]

I just installed an AS as well and learning to run it can be tricky.

Running it at 2.5 seems high but if you have low draft I can understand. How tall is your chimney and do you have any 90 degree bends in your pipe?

Funny you mention this, the other night when I was running my stove I noticed it was popping a little bit. Basically the flames would die, and then like 4 seconds later they would come back and you would hear a small pop sound. Didn't seem like a backpuff. I think it stopped on its own but I cant recall if I did anything as well. Its possible I opened the air a notch or two. Its also possible I closed my pipe damper down some, I dont quite remember.

We also leave the door cracked at startup. There is actually a notch in the door handle that leaves the door cracked a little during startup. I generally run it around 1-1.5 when in full swing. I have a 25' terra cotta lined chimney with 2 90 degree bends. When it gets very cold I need to close my pipe damper to get it to run properly and not over draft.

 

[kearlymad]

"I don’t have a AS but we have a IS. Is there a wire mesh or spark arrester on the rain cap of your chimney? Just wondering if there could be a restriction in chimney. I have only experienced back puffing at start up. I don’t understand how your wood can be to dry. Our wood is in same moisture % as yours and have to many coals left if anything. The smoke coming out of door when reloading is frustrating but I have found if I crack the outside door which is close to our stove it help considerably on the smoke. Also I have my wood close and load fast. I will see if I can find a pic of my stove loaded, if not I’ll take one when I load this morning."



Thanks Slocum, we don't have wire around our chimney cap, it is open. We've learned to deal with the smoke at start up by leaving the door cracked, I have cracked a nearby window but doesn't seem to affect it. NOt that big a problem for us when we leave the door cracked at startup, just thought it might be helpful info re: the backpuffing. Would love to see a pic of how you load the IS.

 

[kearlymad]

No, I don't think your wood can be too dry in most US locales. Maybe in the desert southwest you could get it too dry...
What do you mean, "wants to smoke at startup?" It won't flame with the door closed when trying to start a new load? The stove's not completely cold, right? What is the air setting, 2.5 out of how many? There's no flame in the box at this setting, it's a cat-only burn?
How tall is the chimney? I'd guess it's decent height if it's masonry, though. When was the liner last swept? Much creosote when that was done?
I don't have an AS, although I'm considering one..
Can you more fully describe your startup procedure? You load some wood on coals, have the door cracked until it flames up...then what, close the door and it will flame OK? How long do you burn in the load? You don't hear any hissing or see water on the ends of the splits, right? I know you said the meter shows it is dry.. After an hour or two, the back-puffs are over?

Yes, it doesn't want to flame much when the door is closed at startup and has a hard time getting going unless we crack the door. - The stove IS completely cold - we don't build a fire til the late afternoon normally as the house stays warm enough from the load the night before.

The AS is a hybrid - we don't engage the cat until the stove pipe 8" above the stove reads around 300 per the instructions.

Air setting is 2.5 out of 4.The instructions say to turn down to 1.5 range but if we do after the load gets going either the temps drop too much or we have the backpuffing. This is why I suspect our draft isn't that great.

Chimney is 15-18 feet and as I said, the draft on the Vermont Castings was fine. We had it cleaned 7 years ago just before we removed the stove in order the rent the house. So it is not a creosote problem. I do wonder if there is some type of nest that was built during those 7 years but I can't access the chimney myself so am waiting to have it cleaned the end of the season. In the past we have only had to have it cleaned every 2 years because we built up very little creosote.

Thanks for your input

 

[kearlymad]

I just installed an AS as well and learning to run it can be tricky.

Running it at 2.5 seems high but if you have low draft I can understand. How tall is your chimney and do you have any 90 degree bends in your pipe?

Funny you mention this, the other night when I was running my stove I noticed it was popping a little bit. Basically the flames would die, and then like 4 seconds later they would come back and you would hear a small pop sound. Didn't seem like a backpuff. I think it stopped on its own but I cant recall if I did anything as well. Its possible I opened the air a notch or two. Its also possible I closed my pipe damper down some, I dont quite remember.

We also leave the door cracked at startup. There is actually a notch in the door handle that leaves the door cracked a little during startup. I generally run it around 1-1.5 when in full swing. I have a 25' terra cotta lined chimney with 2 90 degree bends. When it gets very cold I need to close my pipe damper to get it to run properly and not over draft.

You are right that 2.5 is high, when we tried 1.5 per the instructions it wanted to drop the temperature too low for the cat and was very smoky. I suspect the draft isn't great so that's why it works better open more.

The chimney is 15-18 feet. The pipe coming out from the top of the stove makes one 90 degree bend about 4 feet above the stove to enter the lined chimney.

That is exactly what the stove does, no flame then bursts into flame. Normally not a problem but 3 different times it made a loud sound and some smoke came into the room.

 

[Woody Stover]

The pipe coming out from the top of the stove makes one 90 degree bend about 4 feet above the stove to enter the lined chimney.

You can replace the 90 with two 45s for a less abrupt turn and better draft. If that doesn't quite do it, you could add two or three feet to the top of the liner. You would need a transition plate but I'm not sure what it transitions to...Class A chimney??

 

[1000degree]

My husband and I bought a Woodstock absolute hybrid stove this past fall and really like it but are having a couple of issues. Background: we've heated with wood 20 years (1995 VC Resolute, 2011 Buck Stove). The Vermont Castings was in this house with the same chimney (brick chimney lined with insulated stainless pipe) set up and had no draft problems but this stove wants to smoke at start up so guessing the draft is not working as well somehow. We leave the door cracked an inch at startup and this works.

- We are having problems with backpuffing/mini explosions when we have hot wood (red oak, locust, or hickory) loaded and the stove set on around 2.5. Woodstock suggested our wood is too dry - it is 11-15% per our moisture meter. We can open the draft a couple of dots when it backpuffs and that stops it but makes us too nervous to leave the fire unattended the first couple of hours.
- Can someone explain or show a picture of how they fully load the stove? We don't have good coals left in the morning (after 10-12 hours) although the stove is still warm from the soapstone. I suspect we are not loading it full enough. Generally load a 2 small, 2 medium and 2 larger splits on existing coals.

Other than these 2 issues we love the stove - including the looks which I know some don't like. And love that it stays warmer much longer than our other stoves. We live in the NC mtns in a small old house which we have insulated fairly well. We build a small fire in the late afternoon, let coals build up and do our main load early evening. In the morning the house is usually still above 65 and the stove sides often warm but no real coals.

Thanks!

 

[1000degree]

We have been burning our absolute steel hybrid, since feb 1st 2018,
We also experienced back puffing a couple of times. What we have discovered is that when you get the stove up to temperature; ie
350-500 degrees on the stove top gauge,
And the catalyst probe gauge between 500& 1000 degrees, immediately start closing primary air.
This stove does not like to be shut down quickly, we closed the primary air in small increments, several times over the next hour or longer, for a slow long controlled burn.
Anytime our primary air draft was on 2.5 or higher, we felt like the stove temperature got too high with a full load of 15 % maple, ash, cherry - wood.
As soon as our stove reaches 500 Degrees we lower the primary to number 2.
If the stove temperature stabilizes we leave it there, if it continues to climb we lower it to 1.5.
The owners manual has the stove top temperature gauge in the middle of centertop lid. Which is right above the catalyst chamber, which causes it to read a higher#.
We moved ours to the side right above the loading door,
For our stove it seems to be more accurate.
We are also former Vermont casting users,
We were used to adding wood walking away and forgetting about it because the old vermont primary air was thermostatic contolled . The absolute hybrid is totally manual, which in my opinion is the one thing that keeps this stove from being perfect.
One more thing :check your Chimney Cap or the last 18 inches of your chimney,
That is the only place we had any soot buildup or accumulation.
After Building A Fire, the quicker you can get it into Catalyst mode ,the cleaner your chimney will be..
1000 degree...

 

[Woody Stover]

This stove does not like to be shut down quickly, we closed the primary air in small increments, several times over the next hour or longer, for a slow long controlled burn.

Right. You need to burn in the new load sufficiently to burn off initial moisture and get the stove up to the temp where the cat will light off, and so that the load is sufficiently charred to where it is easy for the burn to sustain itself, even if you elect to burn low with no flame. I cut the air in stages too, even though I don't ever get back-puffing.

 

[kearlymad]

You can replace the 90 with two 45s for a less abrupt turn and better draft. If that doesn't quite do it, you could add two or three feet to the top of the liner. You would need a transition plate but I'm not sure what it transitions to...Class A chimney??

The 45 degree turns are a good suggestion. The pipe already extends 3-4 feet above the brick chimney (about 6 feet above the roof), any higher and it would be too difficult to reach it for cleaning.Thanks.

 

[kearlymad]

We have been burning our absolute steel hybrid, since feb 1st 2018,
We also experienced back puffing a couple of times. What we have discovered is that when you get the stove up to temperature; ie
350-500 degrees on the stove top gauge,
And the catalyst probe gauge between 500& 1000 degrees, immediately start closing primary air.
This stove does not like to be shut down quickly, we closed the primary air in small increments, several times over the next hour or longer, for a slow long controlled burn.
Anytime our primary air draft was on 2.5 or higher, we felt like the stove temperature got too high with a full load of 15 % maple, ash, cherry - wood.
As soon as our stove reaches 500 Degrees we lower the primary to number 2.
If the stove temperature stabilizes we leave it there, if it continues to climb we lower it to 1.5.
The owners manual has the stove top temperature gauge in the middle of centertop lid. Which is right above the catalyst chamber, which causes it to read a higher#.
We moved ours to the side right above the loading door,
For our stove it seems to be more accurate.
We are also former Vermont casting users,
We were used to adding wood walking away and forgetting about it because the old vermont primary air was thermostatic contolled . The absolute hybrid is totally manual, which in my opinion is the one thing that keeps this stove from being perfect.
One more thing :check your Chimney Cap or the last 18 inches of your chimney,
That is the only place we had any soot buildup or accumulation.
After Building A Fire, the quicker you can get it into Catalyst mode ,the cleaner your chimney will be..
1000 degree...

Thanks for your insights. Our stove top has rarely gotten to 500 - seems to run 350-450 normally. I have been trying the incremental drop down of the draft and I agree that seems to work better although other users on this site seem to be able to set it and leave it.

 

[John B]

I agree that this stove needs to be turned down in stages. I suspect it has something to do with how the stove internally controls the dampers for the secondaries and cat.

 

[Woody Stover]

I agree that this stove needs to be turned down in stages. I suspect it has something to do with how the stove internally controls the dampers for the secondaries and cat.

I've been thinking about getting an AS. One issue would be my fireplace lintel height; I think I would have to cut off the legs and alter the hearth in the area of the handle to get the ash door to open all the way. The setup would look like arse..it'd be a steel box sitting on the floor.
Another issue might be that, from what I'm reading, the AS likes a little more draft. The Fireview and Keystone will run pretty well on 13' of stack. I have 16' of insulated liner up through a masonry chimney, so that is only one 90* turn in the tee, about 8" behind the rear-vent flue outlet. Maybe it wouldn't be a problem..?

 

[kearlymad]

I've been thinking about getting an AS. One issue would be my fireplace lintel height; I think I would have to cut off the legs and alter the hearth in the area of the handle to get the ash door to open all the way. The setup would look like arse..it'd be a steel box sitting on the floor.
Another issue might be that, from what I'm reading, the AS likes a little more draft. The Fireview and Keystone will run pretty well on 13' of stack. I have 16' of insulated liner up through a masonry chimney, so that is only one 90* turn in the tee, about 8" behind the rear-vent flue outlet. Maybe it wouldn't be a problem..?

That is same setup as our chimney (lined masonry, about the same height, one 90 degree turn). I do love the stove but I think our draft is not quite enough. Note that we are not that cold here, usually burning when 25-45 degrees outside so if you are in a colder area the draft would be better.

 

[kearlymad]

I agree that this stove needs to be turned down in stages. I suspect it has something to do with how the stove internally controls the dampers for the secondaries and cat.

Thanks, been trying that and is working pretty well, we are able to turn air intake gradually down to 1.5-2 after burning at 3 awhile and no backpuffing.

 

[Slocum]

"I don’t have a AS but we have a IS. Is there a wire mesh or spark arrester on the rain cap of your chimney? Just wondering if there could be a restriction in chimney. I have only experienced back puffing at start up. I don’t understand how your wood can be to dry. Our wood is in same moisture % as yours and have to many coals left if anything. The smoke coming out of door when reloading is frustrating but I have found if I crack the outside door which is close to our stove it help considerably on the smoke. Also I have my wood close and load fast. I will see if I can find a pic of my stove loaded, if not I’ll take one when I load this morning."



Thanks Slocum, we don't have wire around our chimney cap, it is open. We've learned to deal with the smoke at start up by leaving the door cracked, I have cracked a nearby window but doesn't seem to affect it. NOt that big a problem for us when we leave the door cracked at startup, just thought it might be helpful info re: the backpuffing. Would love to see a pic of how you load the IS.

I put as much wood in stove that will fit. This load is 16” splits loaded north south. I have some oak that is 20-22” long that I will load east west. I prefer 16” splits north south. There’s hardly any wasted space. If I was you I would have your chimney cleaned. If it’s been seven years and there’s no screen on your flue cap there’s a good chance there’s something obstructing your draft. I would do it for piece of mind.



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[kearlymad]

View attachment 239482
I put as much wood in stove that will fit. This load is 16” splits loaded north south. I have some oak that is 20-22” long that I will load east west. I prefer 16” splits north south. There’s hardly any wasted space. If I was you I would have your chimney cleaned. If it’s been seven years and there’s no screen on your flue cap there’s a good chance there’s something obstructing your draft. I would do it for piece of mind.



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Thanks so much for this picture! WE are not loading nearly full enough after I see this!

 

[kearlymad]

Just wanted to update those who offered suggestions last year for my smoke problem. WE had the chimney inspected this summer and everything looked good, pipe connections all secure within the brick chimney. So the draft decrease from our old stove (VC Resolute) must be because of the different stove design of the Woodstock Absolute. We solved the smoke problem by starting to build top down fires - it is amazingly less smoky and keeps our glass a lot cleaner.