Lopi Leyden problems - low burn time, house smells like smoke, back puffs, etc.

[Fennesseyb]

I bought a used Lopi Leyden woodstove a few years back and have never loved the woodstove. I've tried searching here, and have had some of my questions answered, but still have some where I'm unclear. Couple of my problems:

1) Low burn time: With an outside temp of above 30 the stove works great and can hold heat for a nice long time. Once it gets below 30, it seems the temp really drops fast and can't hold heat. I'm constantly opening the damper to get the temp back up, and closing it down....way more often than I should have to. I've read on here that some will adjust the back damper so it's always at least 10% open, but I can't figure out how to do that.

2) House smells like smoke: zero smoke smell when it's wide open heating up, but when I close it down for an extended burn, the house starts smelling like smoke. It's not enough for the Carbon Monoxide detectors to go off, or the need to open a window, but it's more than it should be. I've replaced the door gasket and the top loading gasket, still the smell.

3) Back puffs a lot. This is most likely causing the smoke smell. Because when it back puffs it forces smoke out at the collar connection most of the time, out the doors at times, and sometimes under the top (the actual top, not lid). This happens whenever I have a fairly full firebox, fire going strong, and I go to shut it down. I always leave the bottom bypass adjustment all the way open. Do I need to replace the combustion chamber? I've taken it apart to clean it, and it looks intact. There are times where it just rumbles (secondary combustion) without puffing, but it's more often than not it back puffs when it starts rumbling. So I have to play the open/close/open/close game with the damper until it settles down.

My current setup: I have the collar adjusted so the pipe goes straight out into the wall (old chimney), it does a 90* bend and straight up the chimney. New chimney liner was installed when I got the woodstove. I probably have close to a 40' chimney (3 story house and chimney extending above the roof). I have a large home (2800 sq feet) and never expected it to heat the entire house, but it does a nice job supplementing the heat. Chimney cleaned annually.

I was hoping to limp along with this stove a for a couple more years before I can get a new one.

 

[begreen]

This is a cantankerous stove that is fussy about draft even when new. Have you checked the refractory assembly for degradation? When this happens the stove can become a real handful to run. If the refractory is ok then my guess is that draft is the issue. This stove wants draft to be in the Goldilocks zone, to little and it back puffs and too much and glows in back.

How could this be a problem with your setup?

The horizontal run from the back of the stove can slow down draft quite a lot. The longer the horiz. run the worse it gets. Then the flue gases have to make a 90º turn up a cold chimney, more slow down. If the chimney only has a clay liner and this is oversized for the stove which needs 6" (28 sq in) then more slow down of draft.

 

[Fennesseyb]

Refractory assembly, is that the combustion chamber? If so, last season I did get back there to check it out. Everything looked intact, and I vacuumed it all out. Nothing about it made me think it needed replacing, although I know many have needed to replace it on the Leyden.

The chimney was lined with a 6" pipe inside the chimney prior to installing the woodstove. I thought about the draft as well, but I have never had issues starting a fire...as soon as there is smoke, it's going up the chimney. Loading wood during a fire has never been a problem with smoke coming back out. I have read where some have adjusted their bypass handle so it closes about 90% allowing more air to pass through even when closed. I know this will hurt efficiency, but if it eliminates a few of my frustrations, I'm game. I'll have to take a look at that tonight.

 

[begreen]

Yes, the combustion chamber. You've done your homework. A manometer test on the horiz. run would determine if that is contributing to the issue. How long is the horizontal run? Is it pitched upward toward the chimney?

How well seasoned is the wood you are burning? Have you tried some dry 2x4 cutoffs in the stove as a test?

 

[Fennesseyb]

Yes, the combustion chamber. You've done your homework. A manometer test on the horiz. run would determine if that is contributing to the issue. How long is the horizontal run? Is it pitched upward toward the chimney?

How well seasoned is the wood you are burning? Have you tried some dry 2x4 cutoffs in the stove as a test?

Horizontal run is less than 3' and I don't believe it's pitched upward towards the chimney.

The wood has been seasoned a year, I haven't tested it though. I haven't done a 2x4 cutoff test.

 

[begreen]

By the book, the horiz. run should be pitched at least 1/4" / ft.

 

[Fennesseyb]

I'll take a look tonight, it probably is - was professionally installed.

 

[webby3650]

These stoves are very unpredictable. I’ve had 2 of them. The first experienced different problems than the second one. First would back puff and blow the lid open, filling the room with smoke. The second one went nuclear, the entire back would glow almost see through orange/white, nothing could be done to slow it down once it took off! Pretty scary, no wonder Lopi discontinued it, even though they would never accept that it was a flawed design.

 

[branchburner]

The wood has been seasoned a year

This could be part of the problem, depending on wood type, storage and how "seasoned" it really is (some call wood "seasoned" if the tree was dropped a year ago but only split yesterday). My Harman with a similar burn technology was pretty fussy in this regard, more so than many other stoves.

I can't speak to the 3' horizontal run, but with a 40' pipe it seems likely you have decent draft. I wonder if when it is colder out you are getting shorter burn times and less effective heat because the draft is TOO good, pulling heat up the flue. Is backpuffing less of an issue in colder temps?

Also: are you taking temp readings of flue, stove top, or back of the stove? (Not sure about the Leyden, but my Oakwood let me measure temps in the area of the combustion chamber, which sometimes ran over 800. If those temps were low, I knew the secondary had stalled.)

And BTW, "professionally installed" is not always the same as "optimally" or "correctly" installed. That goes for the chimney cleaning, too. Does the liner come to a tee inside the chimney, for cleaning purposes? How much creosote is removed at cleaning? Sometime draft is compromised either by a buildup, or by the venting not being a closed system (A few times the bottom cap has been off at the base of my cleanout tee, and that makes good draft a nonstarter).

 

[Fennesseyb]

Thanks for helping me troubleshoot this. I think the smoke smell is more of a backpuffing problem, rather than a draft problem. I started a small fire last night and kept a close eye on it. As soon as the secondary combustion started, a gentle stream of smoke came out the back. I wonder how long this has been happening and I have only noticed the big back puffs? Tonight I'll take off the heat shield off the back and see exactly where that's coming from, it appears it's coming somewhere from behind the shield.

That's a great point about too much draft. I've really noticed the smoke smell now, with the temps in the 30's (and also getting a lot of heat in the house). So to your point about the heat going up the chimney during cold temps makes a lot of sense.

I'll keep trying different things, limp along this season, and get rid of it next year. Thanks for the suggestions thus far.

I've never had it go nuclear like Webby, but have always struggled with the back puffing.

 

[webby3650]

We had an interesting experience with it.
The stove that went nuclear on me was a store display. It always seemed to burn on the hotter side, so I took it home as a comparison to the sluggish one that back puffed. After much trail we found that the Ashpan was made in a way that prevented the drawer from latching down tight all the way around. We contacted Travis industries, they said they changed the design because of this issue. They would only sell us a new one... not provide us with the current pan. They never even sent out any memos to dealers about the issue!

 

[Kevin Weis]

Sounds to me two issues, questionable quality of the stove and the long horizontal run of about 3'. That horizontal run should be eliminated and made into a 45 section with two 45 degree elbows. Will make a world of difference in the draft. Mine did and eliminated my back puff problem. As for the stove, seems folks are saying it needs to go. Kevin

 

[Fennesseyb]

Sounds to me two issues, questionable quality of the stove and the long horizontal run of about 3'. That horizontal run should be eliminated and made into a 45 section with two 45 degree elbows. Will make a world of difference in the draft. Mine did and eliminated my back puff problem. As for the stove, seems folks are saying it needs to go. Kevin

Agreed the stove needs to go, it's just not in the cards right now. The stove actually does have the two 45's that you reference. The two 45's and about a 8" flat piece make up the 3' horizontal I referenced.

In an effort to try and figure out the smoke smell, I started a fire 2 nights ago, filling the box about half full. Got a nice hot fire going and shut it down. No back puffing, no visible smoke escaping. But after about 30 minutes the smoke smell started to surface. I kept a close eye on the stove the entire time, looking closely for any smoke coming out of any of the stove joints....nothing.

So last night I removed the heat shield off the back to expose even more joints, and filled the firebox about 3/4 full. Same thing, after about 30 minutes the smoke smell started to surface, but no visible signs of smoke anywhere.

It almost seems like once secondary combustion slows down or stops, that's when the smoke smell starts to become evident. Would that be a gasket problem? A need for a new combustion chamber? I don't feel like it's a draft problem, but am willing to continue to explore that. This is our third year with the stove and we never had this problem the first year, very occasional the second year, and it seems every time this third year.

 

[begreen]

We need to eliminate the question of the wood first. Did you try a fire with some 2x4 cut offs yet?

 

[Fennesseyb]

We need to eliminate the question of the wood first. Did you try a fire with some 2x4 cut offs yet?

I haven't. I'll do that tonight.

 

[Fennesseyb]

We need to eliminate the question of the wood first. Did you try a fire with some 2x4 cut offs yet?

Did the 2x4 burn this morning and kept a close eye on the stove. Lots of secondary combustion going on inside the stove. Almost every time you would see secondary combustion flames, a small little puff of smoke would come out the back. Back right corner out of the seam. I've attached a photo of the seam where smoke is coming out.

Once the secondary combustion flames slowed way down, the smoke stopped coming out. Smoke was coming out probably every 30-60 seconds at its worst.

The first and second year I owned the stove were probably the greenest wood I burned. This year is the driest wood yet. That could explain why it's so bad this year. The dry wood is creating more secondary burn than ever before. The secondary burn must create added pressure that forces smoke out the back?

 

[begreen]

Can you finger tool some stove cement in there for this season?

 

[branchburner]

Here's the thing about these stoves: when functioning and drafting properly, secondary combustion should be taking place in the rear burn chamber (out of view) as well as visibly in the firebox. And another name for this secondary combustion is "burning the smoke." So if the smoke is being re-burned properly and completely in the afterburner, you should see no visible smoke coming out of your chimney, let alone seeping out of the stove.

Now the problem may not be with the combustion package itself (perhaps it's the damper, or flue, etc.) but it would seem you are having a problem establishing a good secondary burn in the rear chamber such that visible smoke exists. This actually would easily be a problem with a 2x4 test burn, because you are burning super-dry stuff of smaller dimension, giving too much exposed surface area of the fuel and thus creating far too much smoke to be handled all at once. But it shouldn't be a problem with a normal load of well-seasoned splits, assuming proper draft and proper technique (fully closed bypass damper only after fire is fully established, stepping down the air supply incrementally, etc.)

And no, secondary burn does not create added pressure that forces smoke out the back. A good draft should be sucking everything up the stack, and good secondaries should mean none of those gasses are visible smoke.

With my Harman it was important to establish a good coal bed and have the stove hot enough before closing the bypass damper. I don't really know how the Leyden works in comparison, because if I understand correctly it has a damper that is adjustable, with more settings than just either fully closed or fully open. If the bypass damper was anything short of being fully closed I don't understand how a complete secondary could even occur, because it would seem essential that ALL of the gasses are forced down and into the rear chamber for that to happen.

Again:: are you taking temp readings of flue, stove top, or back of the stove? What are stove top temps when you close the bypass? These stoves do have a learning curve and are very subject to variable performance depending on user technique, not just dryness of wood. (I found running mine FAR trickier than with other burn technologies.) And again, are you also sure that from stove to chimney top the venting is a fully closed system that is not compromised anywhere? With such a tall stack it makes no sense that you would have a draft problem, but it does sort of sound like that's a possibility.

If you can describe your procedure from a cold stove, regarding both bypass and air-supply settings as well as stove temps, that might help identify other possible causes.

 

[Fennesseyb]

Can you finger tool some stove cement in there for this season?

I think that's exactly what I'll try.

 

[kennyp2339]

Take it for what its worth but I remember seeing a write up of a gentleman that had the same issues about 7-8 years ago, turns out the rear re-factory chamber was almost clogged solid with deposits / debris which many of the symptoms you described, you may want to carefully take the stove apart and check the rear chamber and clean it out.
Found the write up https://woodchuckcanuck.com/2011/12/18/our-harman-fireplace-wood-stove-goes-boom/

 

[Fennesseyb]

I don't really know how the Leyden works in comparison, because if I understand correctly it has a damper that is adjustable, with more settings than just either fully closed or fully open. If the bypass damper was anything short of being fully closed I don't understand how a complete secondary could even occur, because it would seem essential that ALL of the gasses are forced down and into the rear chamber for that to happen.

Again:: are you taking temp readings of flue, stove top, or back of the stove? What are stove top temps when you close the bypass? These stoves do have a learning curve and are very subject to variable performance depending on user technique, not just dryness of wood. (I found running mine FAR trickier than with other burn technologies.) And again, are you also sure that from stove to chimney top the venting is a fully closed system that is not compromised anywhere? With such a tall stack it makes no sense that you would have a draft problem, but it does sort of sound like that's a possibility.

If you can describe your procedure from a cold stove, regarding both bypass and air-supply settings as well as stove temps, that might help identify other possible causes.

I don't believe my stove has the adjustable damper. I'm thinking my damper is still the original one, not the one that is adjustable. So when mine is closed it's completely closed. Unless I'm just missing how to adjust it.

I'm taking the temps on the top of the stove. I'll usually get it up to around 700* and then shut the damper down.

My process with a cold stove:
1) with a firestarter and some kindling I get a nice hot fire going (usually about 5 minutes or so with the front door cracked.)
2) Adjust the coals to give a nice channel down the middle for airflow - fill the firebox up about half full.
3) When the stove top hits around 700* I'll close the damper
4) After the initial (half full) wood has burned down, and I have a nice bed of coals, I"ll fill the box up.
5) I'll at least get the fresh wood burning (a couple minutes), and then close the damper down.
6) The manual says to close the air control down to low, but I have found that I need to leave it open the entire time, or else the temps drop very fast.

 

[Fennesseyb]

Take it for what its worth but I remember seeing a write up of a gentleman that had the same issues about 7-8 years ago, turns out the rear re-factory chamber was almost clogged solid with deposits / debris which many of the symptoms you described, you may what to carefully take the stove apart and check the rear chamber and clean it out.
Found the write up https://woodchuckcanuck.com/2011/12/18/our-harman-fireplace-wood-stove-goes-boom/

Wow, watched that video...our puffing, even at it's worst, isn't even close to that bad. But the timing is exactly the same...you see the secondary flames, and then the puff of smoke. I vacuum it out a couple times each year, as much as I can without taking it apart. I also make every attempt to keep the ash bed cleared away from the air intake part of the combustion chamber. In the middle of the burning season last year i pulled it apart to clean it completely out. Nothing looked out of the norm - everything intact and wasn't even that dirty.

 

[branchburner]

Take it for what its worth but I remember seeing a write up of a gentleman that had the same issues about 7-8 years ago, turns out the rear re-factory chamber was almost clogged solid with deposits / debris which many of the symptoms you described, you may what to carefully take the stove apart and check the rear chamber and clean it out.
Found the write up https://woodchuckcanuck.com/2011/12/18/our-harman-fireplace-wood-stove-goes-boom/

That was my first thought (since I too experienced it with my Harman, to a lesser degree) but the OP said he had already cleaned and inspected the reburn chamber.

But it does sound like the reburn process is stalling out for some reason, because the backpuff is likely a result of too much smoke being produced for the amount of draft available to pull that smoke up and out. There are so many possibly contributing factors to that, but the fact that it is getting worse this year as opposed to when first installed makes it sound like something has changed, either within the stove itself or with the venting, the wood or the operational technique.

Or perhaps something else has changed the effect draft, like a reduced air supply due to tightening up the house or new appliances using air?

 

[branchburner]

6) The manual says to close the air control down to low, but I have found that I need to leave it open the entire time, or else the temps drop very fast.

So what I found through lots of trial and error is that I had to step the air supply back incrementally for best result. Going from fully open to mostly (or fully) closed would stall out the AB sometimes. So I'd go from full open to 3/4, then to 1/2, then to 1/4. And the timing might vary depending on the type, dryness and size of my fuel, or on what the outside temps were, etc.

But I wonder if leaving the air fully open is helping create a problem. It certainly will give shorter burn times. The backpuffing itself is essentially a series of small explosions where unburned gasses are building up and reigniting in the firebox, which means they are not properly flowing into the reburn chamber for complete secondary combustion.

I found the most reliable way to know my reburn chamber was cranking away was to measure the temps on the rear of the stove, rather than the top. The top might remain in the 500f range, but it the secondaries were engaged the rear side of the stove could easily push 7000-800f. If not engaged, that temp might be only 300-400f. The other way is of course to look outside and see if smoke is visible from the chimney.

When removing the combustion package, do you have to unbolt the rear cover of the stove, as with the Oakwood? In addition to cleaning it and ensuring nothing on it has degraded or broken, it is very important to re-seat it correctly when replacing, and to ensure all the gaskets and other refractory components (like "shoe brick") are also intact and correctly positioned. I had a problem with this more than once in servicing my Harman.

That Oakwood thread with videos that was linked has a long comments section with some interesting observations, including this one near the end:
"The first 2 years the stove worked great. We have it in the basement, which wasn’t finished at the time, but had insulation up. In 2013 we finished the basement and after that we’ve had nothing but issues with smoke smell in the house, the huffs of smoke coming from the top, etc."

So that was likely a change not in the stove itself, but perhaps air supply. Any changes in your house?

 

[MisterFixIT]

Lopi Leyden! Hey I remember that name. Ran one for 8 years. My first stove. It was expensive (3500$ in 2008) and it was terrible.

Replaced combustion package after 5 years ... totally clogged with ash. Also took apart and regasketed the top of the stove.

Ran it another 2.5 years and started clogging up again. Ran away in the wind and the back glowed red all the time. Stuffed a insulated BBQ glove up into the air intake to try to keep it from going over 750F. What a nightmare.

Finally smoke smell. The back cast iron was cracked, combustion package clogged up with ash again and the bypass door would not stay shut.

It was finally dead... the best day of my life.

Replaced with PE and never want a top-loader or a stove with a by-pass door again.

Kept the cool Eagle andirons to remember it by.