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Let the big cat eat! Buck 91 up and running. Advice, tricks and tips welcome...

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by Woody Stover, Dec 6, 2012.

  1. Woody Stover

    Woody Stover Minister of Fire

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    This may be the key. Wife was in town, so she loaded the stove. There were some split shapes left (which crumbled when she raked them to the front/middle. They were probably giving off blue flame, but she couldn't recall as she had also put a couple of splits on to bring up the temp for the reload. With the bypass open, probe temp went to 1140. :ZZZShe loaded up, got some flame in the middle with the shotgun air, and was off to the races. Probe got up around 1500, stove to 500, and then leveled off. :cool:
    The times lately when I had trouble getting to cat to take off, I had most of the coals in the middle, big wood on the sides. I loaded a couple small ones in the middle to get that area hot quickly, but put some bigger splits on the top of that. I gave it air, figuring that the heat from the flames would come out the back of the 16" splits and heat the cat area, but apparently that doesn't work. This AM I had coals in the middle but just small stuff on top, and got big flame coming up to the shield. Closed the bypass and the cat took off nicely to over 1000. Cut the air back, turned on the blower, and cat temp didn't fall much. I'll keep starting this way with big flame able to come out the top of the load unrestricted. Hope I didn't buy a cat for nothing but I'll put it in, and do expect to see improved performance. I like to have a backup cat around anyway...

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  2. Woody Stover

    Woody Stover Minister of Fire

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    OK, I put the new combustor in on Thursday...yep, the old one was tired. Glad I didn't spend my money unnecessarily. >> I'm still going by the book and engaging when it's close to 700 on the probe and wow, she lights off pretty quick and no worries about a stall. I restart the blower at about 800, and see little drop in the probe temp. I'm seeing no smoke at about 900, vs. 1200 with the old cat. Neighbors will be happy. :cool: I expect to get more heat as well, now that more smoke is being burned. I replaced the ash pan gasket several weeks back, hoping to stem the air coming up through the ash dump lid, but it slowly developed a similar gap where the ends of the rope gasket meet. I think with repeated contact with the pan housing, the strands at the rope ends loosen up. I ran a couple ideas by the folks at Buck, one being to fill in the gap with silicone. They emailed back almost immediately, saying 'Yes, that will help.' So far, customer support from Buck has been outstanding with quick email responses and informative answers to my questions. Anyway, I ended up using gasket cement to glue a small piece of rope into the gap. We'll see how long that holds up... I might also try replacing the rope with a flat gasket at some point. Anyway, the results are outstanding! The left side of the box still burns a little faster than the right but there are some decent chunks remaining on the left after a 12-hr. burn. Before, there was nothing but ash over there. The load is burning more in the middle of the box instead of on the left with too much flame. The result has been a longer burn with good heat output after 12 hrs. 600 probe, 250 stove top and house temp a good bit higher. I haven't had to burn any sacrificial splits to get stove temp back up for the reload, just pull some chunks/split shapes forward and open the air a bit to get up around 700, then reload. I'm no longer concerned about the cat temp going high now that I've got better control of the air. I may adjust the air slider plates up to allow me to cut the air even more, if I desire.

    I recommend that all Buck owners check for a gap at the ends of the ash pan gasket if they want to be able to run their stove slower. It's made a huge difference in my case. Not sure if other Buck models have a similar ash pan gasket?

    I just saw that the door latch pawl(?) is too far back, and partially hitting the plate steel...easy fix by loosening the set screws (I mistakenly said it had a roll pin earlier.) Actually, one screw is missing and you can see the edge of its hole in the pic.
    [​IMG]

    Now that I'm finally getting the stove set up right, I'm sure it's going to do everything I ask of it and it'll be much easier to run, to boot. I'm one happy camper, and lovin' this stove more all the time! ::-)

    A revised burn-time report is forthcoming. ==c
  3. WoodpileOCD

    WoodpileOCD Minister of Fire

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    Good to hear you are getting the beast tamed and tuned. I have never even had my ash drawer out so I will have to take a look at that. I don't think you said but how hot is your cat running now. Are you able to get it to the 1500 - 1800 range pretty easily now? Also what kind of cat did you get and where?
  4. Woody Stover

    Woody Stover Minister of Fire

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    Yeah, I'm really pleased with the way it's going.
    Like I said, there is still a little air coming in at the ash drop but nowhere near what it was. I cleaned the glass last night and only had a little brown haze in the lower corners this AM. :) Contrast that to the previous clean left-side glass due to the ash pan leak inferno, and gunked-up lower right glass. Now that I'm getting a longer burn with stronger, more even heat output, I don't have to cram the box full. I don't have to push the coals to the back to make room for wood, I just heap 'em up in the middle, N-S. Then I can load the 16" splits further back, away from the glass. That may help keep it cleaner, I don't know. Just sealing the ash pan leak is getting more air coming in through the air wash, I'm sure. We had 69* in the furnace thermostat room, next to the stove room, this AM. No, it wasn't too cold last night, around 40, but the wind was pretty strong.
    I never had a problem getting high cat temps. In fact, I was more worried about it going too high. I don't think that's going to be an issue any more, with more control over the air. The problem was getting the cat to take off with a new load. And even with the cat glowing away there was still some smoke out of the stack. Besides a tired cat, that have been partly due to too much air (cool ash drop air at that) moving the smoke too quickly through the cat and not giving it the time it needed. Hard to tell what actually happened since I made two changes at once (new cat, fixed air leak.) Highest cat temp I've seen with these changes has been 1200. Waiting for more recorded daytime readings to come in from further into the burn...
    I may keep burning sacrificial splits to raise the stove temp if I need to. That way I can get big flame and radiation against the walls of the box. Once you have 'er loaded up, radiation against the sides is limited. This AM, MIL had opened up the air a bit when she got up, and I was ready to load up as the probe was already around 700. By the time I had 800, cat was glowing and no smoke. :)
    The replacement cat is OE, Applied Ceramics from firecatcombustors.com, the site that AC directs you to. I will be starting a thread about that soon. :mad:
    Yep, I'm stoked about the situation now. I think I'll be able to get 12 hrs. of good heat on lesser fuel, like soft Maple. This would sure take the pressure off since I should be able to dry quite a bit of that this summer. Hopefully I can save the slower-drying high output woods for those colder-than-average nights. Once I get far enough ahead, it'll be a moot point and I'll burn whatever the hell I want. >>
    Gonna get cool this weekend; Might have to stuff 'er to the gills with Hickory and BL, and go for the Long March burn. ==c
  5. _CY_

    _CY_ Burning Hunk

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    just installed a used Buck 91 .. barely getting 1,000f degrees max after getting box good and hot before engaging cat. just not putting out enough heat

    time for a new cat? there's all sorts of instructions on the web, on how to clean your old cat... is it worth cleaning or just order a new one and be done?
  6. mellow

    mellow Resident Stove Connoisseur

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    Where are you measuring that temp at?
  7. _CY_

    _CY_ Burning Hunk

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    at the cat with thermometer next to damper handle. did get 91 up to 1,500f last night.. today could barely get it pass 800f ... thinking intake air dump is clogged inside.

    took the cat off yesterday and made sure it nothing was plugging it up. a few cracks showing.
  8. omnipotent

    omnipotent New Member

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    Hey guys, well I got the Buck fired up again (in another thread I was contemplating getting a new one) but after reading these threads a fixing some air leaks, I'm now able to control the flame and no more run away burns....so ordered yet another CAT (last 2 were damaged due to high heat and flame impingement) so I will give it on more go before replacing unit. Now question....how in the heck do you see your CAT? Maybe they changed designs (I don't know how old mine is, it was here 3 years ago, and I'm guessing he had it for 2-3 years before that. With the heat sheild in place I don't see how you could see it....through the air wash holes?

    Also, I read a lot about the blower and it affecting heat output....actuall cat probe heat....not sure how this would affect this since the blower is actually grabbing heat from the enclosure (around the enclosure I guess is a better way of saying it)...so not sure how that would change internal probe temp?

    Lastly, I know everyoneis trying to get that heat up, but as someone who is on his 3rd Cat,I will tell you, I'm happy to burn in the 1200's and never get higher.

    Well, another lastly....E-W vs N-S...I've done both, when I do E-W I rake all the coals to te front righ up to th air intake, then load the wood from the back stacked as high as it will go, then smaller in front and smaller still until it looks like a ramp of sorts. The air wash has a natural flow from front to back, so the first log(s) light and then slowly as they burn to coals, light the logs behind it until it gets to he end. The air wash helps to push the heat back and ignites the logs well. This burn doesn't get as hot as N-S, but can definitely burn all night.

    I use N-S when it's 30's out and need more heat, I rake all the coals to right side and load up from left to right, 2 rows high....this burns hotter and not quite as long, so it's all about how much heat is desired.

    Anyway, thanks for all the tips....I might be able to save this old abused (by previous owner) Buck after all.....
  9. pgmr

    pgmr Feeling the Heat

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    I cleaned ours this year and it made a huge difference. Used the hot vinegar and distilled water method.
  10. Woody Stover

    Woody Stover Minister of Fire

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    I had forgotten about that, but yeah, I think if you look through the air wash holes you can see the glow reflecting from the top of the heat shield. I usually look through the bypass rod hole. It's hard to see, and you have to move your head around to get the right angle. My 91 is an '08. I don't think they have changed the design much over the years. That might be something to email them about....they've responded well to any questions I've had.

    It does change the reading on the probe but I think conditions at the cat are still pretty much the same. Turning on the blower can drop the cat probe reading by 100 degrees or so.

    Manual says the sweet spot is 1500-1600. You're really crankin' out the BTUs then. I've got some bigger splits now, and I'm really not too concerned that the cat is going to go high (I try to get them to record some readings further into the burn, when I'm not there, but that's hit and miss.) Actually, I'm more worried about a crash from not letting the reload get burning fully enough after closing the bypass and before cutting the air to the cruise setting. I had one crash when I tried to leave too soon the other day. I saw the probe temp rising from 900 and thought it was lit off, but apparently not. When I went back to load for the evening, I saw a recorded reading of 600, a couple hours into the burn. The temp on the probe will rise even when the cat isn't lit, if you have flame in the box. Obviously this is the case, since the probe can be rising even if the cat isn't engaged. After I close the bypass and burn more flames for a while, then close the bypass and cut the air, if I see the probe rising over 1000 at a pretty rapid clip, I'm pretty sure it's lit off, even if I don't see it glowing yet. You can also sometimes hear a knocking sound, which I think is the cat frame expanding in relation to the stove top which it's bolted to.

    I haven't burned N-S much at all; I'm gonna have to play with that a bit. I can generally get twelve hours, even on a load of soft Maple, Cherry etc. Heat is dropping below 200 quicker than with an Ash or Oak load, though....

    Good on ya! You're a tinkerer after my own heart. :cool:

    So far, burning this stove has been easier this season, and I think I may be getting a handle on it. >> Locust Post has a new 91 this season and things are going well for him. He says he can get quick light-off at lower temps than I usually attempt, so maybe it's a difference in our setups, fuel or whatever....
  11. omnipotent

    omnipotent New Member

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    Ok, so new "issue"....I'm getting a good burn rate (8 hours +) and when I come down in the morning, cat probe is still usually ~800 or so. Issue is I'm getting a lot of "coal"...not hot coals for relighting or heating purposes, but wood that didn't burn through and literally turns to coal. I feel like I might need more air to get a complete burn through, but then I'm worried about the fire running off in the middle of the night and burning the load to quick, or getting too hot when nobody is around to watch it.

    I've been dialing down the shotgun all the way closed and leaving the Air Wash (what a joke that term is BTW), about an 1/8 to 1/4 in (really hard to measure :D )....so what's others thoughts...are you getting complete burn through and just soft white ash or are you also getting coal left in the morning?
  12. mellow

    mellow Resident Stove Connoisseur

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    I get chunks toward the rear of the stove as well, but usually I have enough hot coals back there to rake forward and start the fire going again.
  13. clemsonfor

    clemsonfor Minister of Fire

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    If your getting the charcoal hunks of wood that are unburned your draft is not good enough or the air is cut to low.

    I get a few pieces toward the front if I cram too much up front in the bay windows. It burns back and leaves the ends toward the front without coals to burn them. But in the middle or rear the only charcoal I get is small and usually sparse.
  14. omnipotent

    omnipotent New Member

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    Thanks for that...usually the "coal" is on the left side of the box (I load N-S) since I rake the coals to the right side and burn rigth to left. I'm gonna give it a bit more air tonight and see what happens.
  15. omnipotent

    omnipotent New Member

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    Alright, another question....in noting the "glow of the catalyst" I was able to see it last night, well more actually the glow reflection from the heat pan...anyway, today I loaded it with a couple of decent splits, got the cat probe temp to 600, closed the bypass and left the air wide open. Temp got to 800-850 and stayed there....there was no "glow" from the cat and temp never got any hotter even though both primary and secondary air was wide open. This is a brand new cat, just installed and burning year old (split & stacked for a year) Oak....same wood I burned last night, so not sure why Cat isn't lighting off and increasing heat exponentially at this point.

    thoughts?
  16. clemsonfor

    clemsonfor Minister of Fire

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    Cat does not always glow. Will only glow when there is lots off off gassing. You can glow one night with probe at 1200 and another night?? Just the behavior of it. I think applied ceramics even notes this in liturature.

    When I burn I rake coals forward as much a possible. I also burn north to south.

    For the record I have a high valley 2500 but looks and in design is very similar to a buck 91.
  17. omnipotent

    omnipotent New Member

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    Yeah not worried too much about the glow but more about the temp...it's been 2 hours sitting at 850, just won't climb any higher. Cat must be engaged as there is no visible smoke from chimney. I shut down the air controls to get a nice glowing coal bed and blue flame, but temp still hovering around 850. Don't recall this in past years....possible the wood isn't as seasoned as it should be, but still would expect the cat to take off after an hour or two sitting in the 850's.
  18. clemsonfor

    clemsonfor Minister of Fire

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    850 is active. I'd say anything above about 700 depending upon condition of the cat is active. But with only a few splits there is limited smoke to make it climb so high as well is there is not enough to glow red. Its eating if u have no black or blue smoke and its sitting at 850 with very minimal flames.

    I changed mine this season as I had them fail last year. I think I burned most. Of last year with failed or partially functioning cats. I would get the right temps but still have smoke and I creosoted like crazy!!
  19. Woody Stover

    Woody Stover Minister of Fire

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    When I go back over there after ~12 hrs, depending on how much wood I loaded, I'll have a varying amount of coals, but the wood is still burning. Stove temp might be 200-400. I think most of the unburned stuff would eventually burn, but the stove wouldn't be putting out the heat I need at that point. When I let the stove burn out, I may have a few unburned chunks but not too much. If I opened up the air at the end, it would all burn down. Cruise air setting for me has been shotgun closed, airwash slider out about 1/2" or so. When loading, I put the coals in the center and load wood on the sides, and a couple of smaller splits partially covering the coals. When I come back to reload, the left side is usually ashes, which I attribute to the ash dump leaking a bit of air. I find it strange that you have unburned wood on the left side, but maybe that's due to an air leak somewhere from the over-firing, that feeds the right side of the box more air. I may have an intact split still burning on the right side. I pull that to the center, throw on a small split or two, and open the air to get some flame and bring the probe back up to 800+. I find that if I get a good amount of flame, with the smallest possible amount of air, temps come up the quickest. Then I load, leave the bypass open and burn in the load (again, flame with the least amount of air.) Around 850-900, and the load burning decently, I close the bypass (manual says 700-900 before closing the bypass, but some have reported being able to light off at lower temps.)
    The cat wasn't lit, and the increase in temp was due to the heat from the wood burning in the box.
    Cats need the "three Ts;" Temp, Turbulence (provided by the expanded-metal screen below the cat,) and Time. If you have the air open too far and the cat isn't hot enough, smoke will get pulled quickly through the cat before it has a chance to burn in there. When closing the bypass, I'll let some flame burn for a few minutes but then I'll start cutting the air close to my cruise air setting. Less air=less flame=more smoke for the cat and more "Time" in the cat. When I see that probe temp rising over 1000, I'm pretty sure it's lit.
  20. Woody Stover

    Woody Stover Minister of Fire

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    Agree with clem, you only loaded "a couple of splits," therefore not a lot of smoke for the cat to get really hot.
  21. Woody Stover

    Woody Stover Minister of Fire

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    If I was with the stove all the time, I would burn full loads (which I do anyway) but open up the air toward the end of the burn to burn down the coals and slower-burning chunks, and get more heat off the stove at the end of the burn. Sometimes I show up to load and I've got a ton of coals in there. I just run a shovel under them and try to get the fine ash off the bottom, roll off any big coals, and down the ash dump it goes. That way I can make a bit more room for wood in there. Plus, when I throw a coupe of small splits on to bring up the temp, the coals will burn down further.
  22. clemsonfor

    clemsonfor Minister of Fire

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    I use to, on a hot reload, load wood and char the load good. Then shut bypass and slowly reduce air till cruise. But I'd have wild flames and a draft like a freight train was in my chimney!! I was worried about flame impingement with new cats in this season, even though they sit in a trough that is covered from the bottom I think it was pulling them in through the sides. NOW I load stove, hot reload, and reduce air to pretty much cruise level an then throw bypass so that I don't have giant flames washi g my cats. Those things are $197 a pair I'm gonna take care of them. Also its usually plenty hot buff in there and plenty of smoke for ligjtoff my manual says 500f but fire at says like 20-30 mins of 600f I think?
  23. clemsonfor

    clemsonfor Minister of Fire

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    I do this I will cut the air up so that I can get more heat and to burn that coal. This is usually in the afternoon when I return home.
  24. mellow

    mellow Resident Stove Connoisseur

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    I am noticing mine are liking to be around 900 before I can shut it down and it will cruise, last year I could shut down sooner. However I just did start burning Tuesday night so only got 2 days under my belt for this season.
  25. clemsonfor

    clemsonfor Minister of Fire

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    Been burning g since Friday. And going 24/7 even though in sc. I have a leaky old, large house and we just brought home our new baby so I want it warm, like 72 ish for him . He is staying far from stove room so I am burning loads I usually would not burn, I don't like to sleeo at 71 but he does I guess. I'd rather him be at 69 or 68 but wife wants warmer. We use to never sleep that warm. And 2 night ago it was 26 here and last night was 23f.
    ddddddden likes this.

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