Too much air?

[Bmore]

Hey All,
I am in my second week burning a Buck 91. I get a good amount of flame through out the burn cycle even with the air slides completely closed. Is this normal? I thought I could choke the fire out by closing but it just slows it down. Door seal seems good and tight on a dollar. Maybe a leak at catalyst?
Thanks

 

[mellow]

I would try running an incense stick around the gaskets on the door to see if the smoke gets sucked in. I just noticed on my door while I had it apart that the air slides do not fully close even though they look like they do.

 

[bholler]

Modern stoves dont close down all the way there is a minimum amount of air that they allow in so you cant shut it down to hard. I dont really agree with it but that is how they are

 

[begreen]

Choking the fire down to a smolder would turn the stove into a smoke dragon. That is the antithesis of its design.

How tall is the flue liner connected to the insert?

 

[Bmore]

Choking the fire down to a smolder would turn the stove into a smoke dragon. That is the antithesis of its design.

How tall is the flue liner connected to the insert?

My liner is 25'. I don't want to burn that low. Just wondering if I am losing burn time from a leak. My insert was used prior so I worry about seals. Currently get 8 hours overnight with the air sliders closed. I like that I can shut it all down and know it will still burn. Just didn't know if that's normal.

 

[mellow]

You should be getting longer than 8 hours with that much firebox, I get that easy with mine. I think with some practice you will get it down and be getting 12 hour burns.

These stoves are redesigned smoke dragons, don't worry about smoking the wood as long as the cat is active you are fine, I try to keep a small active flame in the box just so I do not have puff backs.

Tell us your current burn process, like what cat temp do you close the damper etc...

 

[HotCoals]

I concur you have a cat stove you should be able to cut it back to no flame.
Leaking air somewhere.

 

[rideau]

Or maybe very strong draft. He has a tall chimney.

 

[Bmore]

At 8 hours there is just enough coals to light kindling. I close my damper at 400f. It steadily climbs to 1000f. It stays between 800-1000 so I figure the cat is lit. Without closing the damper I burn up all my wood by the time it gets 600f. When closed it takes off, but keeps a steady flame with all air shut off. Seems to be ready for a reload at 5 hours time. Burning oak, one year stacked. Moister is below 20%.

 

[Diabel]

Burning oak, one year stacked. Moister is below 20%.

I got my popcorn.

 

[mellow]

Cat should be going higher than that if you are only getting 8 hour burns, something is fishy here. I would check your interim gasket you used on the cat and make sure it is fully sealing and as well double check your door gaskets.

 

[Bmore]

The new cat did not fit tightly and may have created a leak. There was a 1/2" gap or so on one side. I ordered the interim and cat wrap gaskets but it also came with another flat rope type gasket. I used that to seal the gap and coated it with 2000f furnace cement. Would that have sealed it or maybe it failed at the thicker gasket material?

 

[Ashful]

Burning oak, one year stacked. Moister is below 20%.

Only if it was stacked in a kiln or attic. How're you checking that MC%?

 

[Bmore]

Only if it was stacked in a kiln or attic. How're you checking that MC%?

I used a moisture meter. It says the splits are 10-13% on the face. I split a few to check the middle and it was below 20%. Not sure how accurate my meter is. It is new from Home Depot but does not have prongs. It scans more like a stud finder. The trees I cut were all already down. Not sure how long they sat. I single stacked everything around the perimeter of my yard and covered the tops.

I have been getting longer burns loading EW. And filling up the box. Before I was putting 3-4 large splits at a time.

 

[BobUrban]

Forgo the incent stick if you hate the smell(like me) and just run a lighter around the door. If there is a leak the flame will be sucked into the stove and it will be obvious.

 

[jeff_t]

Seems like I remember reading about tightening up the sliders, bending the rods, or something like that. Like, they're closed like they should be, but aren't tight against the air inlet.

Is there an ash pan?

Where's @Woody Stover?

 

[mellow]

Here is the links to woodys threads on his MIL's 91:
https://www.hearth.com/talk/threads/the-buck-stops-here-91-bay-heater-install-under-way.92228/
https://www.hearth.com/talk/threads...running-advice-tricks-and-tips-welcome.100464

 

[Woody Stover]

Burning oak, one year stacked. Moister is below 20%.

I got my popcorn.

Only if it was stacked in a kiln or attic. How're you checking that MC%?

I split a few to check the middle and it was below 20%. Not sure how accurate my meter is. It is new from Home Depot but does not have prongs. It scans more like a stud finder. The trees I cut were all already down. Not sure how long they sat. I single stacked everything around the perimeter of my yard and covered the tops.

Not sure about the accuracy of that type of meter but if the trees were dead when cut, sat for several years...could be as dry as you are reading, although it still seems unlikely for Oak.

I have been getting longer burns loading EW. And filling up the box. Before I was putting 3-4 large splits at a time.

Mine will burn 12 hrs. with still decent heat output, on good hardwoods like Oak or Hickory. It will have some coals after 24 hrs. but no heat to speak of.

The new cat did not fit tightly and may have created a leak. There was a 1/2" gap or so on one side. I ordered the interim and cat wrap gaskets but it also came with another flat rope type gasket. I used that to seal the gap and coated it with 2000f furnace cement. Would that have sealed it or maybe it failed at the thicker gasket material?

That doesn't look like the cat in mine. Where did you get it? But a leak around the interam gasket wouldn't make the stove burn hotter; That will be a function of how much air is coming into the fire box.

Seems like I remember reading about tightening up the sliders, bending the rods, or something like that. Like, they're closed like they should be, but aren't tight against the air inlet. Is there an ash pan? Where's Woody?

Oops, caught me nappin'!

Here is the links to woodys threads on his MIL's 91:

Thanks, mellow. Rather than wade through those threads, I'll distill the nuggets of my present state of evolution with the 91.
Bmore, if the stove is used, I'd replace the door and ash pan gasket for sure. Having 25' of stack, any air leaks will be magnified in your setup. I have 21'. Use OEM gaskets, as they have the proper densities to do the job. Make sure you have the ash pan gasket up high, across the top. The one I just replaced, I let it get a little low in the middle, so rather than tear it off and re-do it, I just slipped a piece of sheet metal in the bottom of the ash pan housing to bring the entire pan and gasket up a little higher for better contact, until I get around to replacing it. It is sealing pretty well. You can tell if the ash pan gasket is leaking by the way the load burns. If you see a lot of hot coals around the ash dump lid, you know air is coming in there. I also replaced the door gasket and I can tell that it helped because the glass is staying clean except for the bottom corners, even though I cruise with the air pretty low (left slider closed, right slider about 1/4" open.) I used high-temp (700 intermittent) copper silicone from the auto parts store. I also dabbed a little on the ends of the gaskets to keep them from unraveling over time. When I got the stove, there was a huge gap in the ash pan gasket where the ends met.
If you look under the 'hearth' (ash lip,) you can see the workings of the air sliders rods and plates. One of the first things I saw, as jeff_t mentioned, was that the plates aren't tight to the air inlets. You could bend the rods, but I chose to take a more easily reversible approach...I just cut a trim coil strip and wrapped it around the bottom of the saddle for the slider rod. I did this on the right side only, the left side didn't have quite as much gap. I may try to tweak all the air plates more closed to go for a longer burn, but I think the risk is a back-puff if you try to run the air too low, depending how strong the stove is drafting due to outside temps, etc. The way I have it now, you can't cut the air enough to crash the cat or get a back-puff. I kinda want to keep it foolproof in case my wife or SIL loads the stove. But I can run without flame if I want. This also depends on how much of the load you have gassing when you cut the air and cruise....you may get intermittent flash-over flame for a while. Yeah, if the cat probe is holding 800+ even when you cut the air, the cat is burning. If it gets up to 1000 or so, you will begin to see the cat glow if you look in around the bypass rod hole.

 

[Bmore]

Not sure about the accuracy of that type of meter but if the trees were dead when cut, sat for several years...could be as dry as you are reading, although it still seems unlikely for Oak.
Mine will burn 12 hrs. with still decent heat output, on good hardwoods like Oak or Hickory. It will have some coals after 24 hrs. but no heat to speak of.
That doesn't look like the cat in mine. Where did you get it? But a leak around the interam gasket wouldn't make the stove burn hotter; That will be a function of how much air is coming into the fire box.
View attachment 146837
Oops, caught me nappin'!
Thanks, mellow. Rather than wade through those threads, I'll distill the nuggets of my present state of evolution with the 91.
Bmore, if the stove is used, I'd replace the door and ash pan gasket for sure. Having 25' of stack, any air leaks will be magnified in your setup. I have 21'. Use OEM gaskets, as they have the proper densities to do the job. Make sure you have the ash pan gasket up high, across the top. The one I just replaced, I let it get a little low in the middle, so rather than tear it off and re-do it, I just slipped a piece of sheet metal in the bottom of the ash pan housing to bring the entire pan and gasket up a little higher for better contact, until I get around to replacing it. It is sealing pretty well. You can tell if the ash pan gasket is leaking by the way the load burns. If you see a lot of hot coals around the ash dump lid, you know air is coming in there. I also replaced the door gasket and I can tell that it helped because the glass is staying clean except for the bottom corners, even though I cruise with the air pretty low (left slider closed, right slider about 1/4" open.) I used high-temp (700 intermittent) copper silicone from the auto parts store. I also dabbed a little on the ends of the gaskets to keep them from unraveling over time. When I got the stove, there was a huge gap in the ash pan gasket where the ends met.
If you look under the 'hearth' (ash lip,) you can see the workings of the air sliders rods and plates. One of the first things I saw, as jeff_t mentioned, was that the plates aren't tight to the air inlets. You could bend the rods, but I chose to take a more easily reversible approach...I just cut a trim coil strip and wrapped it around the bottom of the saddle for the slider rod. I did this on the right side only, the left side didn't have quite as much gap. I may try to tweak all the air plates more closed to go for a longer burn, but I think the risk is a back-puff if you try to run the air too low, depending how strong the stove is drafting due to outside temps, etc. The way I have it now, you can't cut the air enough to crash the cat or get a back-puff. I kinda want to keep it foolproof in case my wife or SIL loads the stove. But I can run without flame if I want. This also depends on how much of the load you have gassing when you cut the air and cruise....you may get intermittent flash-over flame for a while. Yeah, if the cat probe is holding 800+ even when you cut the air, the cat is burning. If it gets up to 1000 or so, you will begin to see the cat glow if you look in around the bypass rod hole.
View attachment 146839 View attachment 146840

Thank you Woody Stover,
I have purchased a new door seal and will check the sliders when we get a break in the weather. I purchased the cat from Clear Skies Unlimited, catcombustor.mybisi.com . It was under $200 at the time and is now $250. Much cheaper than the ceramic OEM replacement. I previously posted a thread asking if anyone had tried this new type, but didn't get much feedback. I will let everyone know how it does, although I have never used the pricey ceramic ones. To compare to.. The new cat is only 1" thick and looks like a sponge. They claim it was designed for open fireplaces and is not impacted by direct flame contact. Also said it can be ignited at lower temps around 400f. I found this to be true. I close the bypass even shy of 400 and it quickly climbs to 800-1000. I Like the very fast start up time. Just would like the longer burns you speak of. Thanks!

 

[Woody Stover]

I purchased the cat from Clear Skies Unlimited, catcombustor.mybisi.com . It was under $200 at the time and is now $250. Much cheaper than the ceramic OEM replacement. I previously posted a thread asking if anyone had tried this new type, but didn't get much feedback. I will let everyone know how it does, although I have never used the pricey ceramic ones.

I musta missed that post. Those fly-by-nighters ripped me off; I ordered 2 cats for the Dutchwest a couple years ago, but only got one. They never answer their phone, and multiple emails to a good address went unanswered. Luckily, I only lost $40. Next time I visit my Sis in NM, I'm gonna drive by their office and run over their mailbox. The ceramic cat for the 91 is around $290, so I would go for that one next time if the Brillo pad craps out and is $250 to replace.

Also said it can be ignited at lower temps around 400f. I found this to be true. I close the bypass even shy of 400 and it quickly climbs to 800-1000...Just would like the longer burns you speak of.

I generally get about 800 on the cat probe before I close the bypass so that the cat takes off quick and I'm not running unburned smoke through it for very long. If you read some of the Buck 91 threads, though, you'll see that other guys closed the bypass at much lower temps. Get a handle on the air entering the stove, and the 91 will get the heat into the room instead of up the flue, and your burn times will stretch...

 

[mellow]

I tell you what, this is the best wood I have ever had and I am able to close my bypass with my ceramic cat down at cat temp of 450 on my stove, good wood makes a huge difference as well.