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Vermont Castings Encore 2550 - Refractory Assembly Question (w Pictures)

Post in 'The Hearth Room - Wood Stoves and Fireplaces' started by oldAGE, Feb 1, 2008.

  1. oldAGE

    oldAGE Member

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    Hello folks -

    Today I removed my upper fireback from my VC 2550 CAT stove. Many know that I have been fighting an over fire situation where my stove with Primary Air closed will burn two splits and hit upwards of 700 degrees. Engaging the CAT (brand new Condar) I would not get the classic rumble. In short, the stove has not been behaving as it has since Christmas. I have had this for 7 years (installed new) and have learned its traits to the letter.

    In my quest for looking for leaks, bad joints, etc, today I removed the upper fireback. Enclosed are pictures of my refractory assembly (CAT removed). Please tell me your opinions upon reviewing the photos. Thanks again to those who have been providing me outstanding assistance regarding this issue.

    AGE

    Attached Files:

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  2. swestall

    swestall Minister of Fire

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    Its hard to tell from the pics but the top part certainly looks deteriorated. Aren't they warranteed?
  3. webbie

    webbie Seasoned Moderator Staff Member

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    Looks to be in reasonable shape - I think that stuff on the top is just cement for where it fits against the stove.
  4. downeast

    downeast Guest

    That refractory box simply sits behind the fireback and under the damper. Missing in the pic is the cat and the "refractory access panel" covering the cat. No cement used, but it damn looks like sheetrock screws ( !!) are used to hold the pieces together. High tech ass'y.
  5. oldAGE

    oldAGE Member

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    OK - So no concensus. The interesting point is that the Upper Fireback has a notch in it that, when mated to the lower fireback, creates the path for flue gases to enter the refractory. The back edges of the notched perimeter has a tongue and that tongue fits into the groove that is visible along the top and upper sides of the refractory. It is evident by the rust stain across the top and the upper left side. The right side is broken down quite a bit. I would venture to guess that the upper fireback no longer makes a seal to the refractory where it is broken away. When damper is opened, most of the flue gases enter the upper fireback and out the stove pipe. The secondary air also adds air so when the primary is completely closed down, secondary air can still enter the stove body and air channels by seeping back through the broken down refractory. When damper is closed, a portion of the flue gases are not forced through the CAT, mixed with air, and out the flue channel but rather finds the path of least resistance through the holes and out. This possibly causes more air to be drawn into the secondary and adds to the over draft.

    Now I have to quickly find a new and reasonable refractory assembly with the access panel. And yes, it looks like sheet rock screws hold the refractory together.

    AGE
  6. swestall

    swestall Minister of Fire

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    Yeah, but they are the Vermont Castings, High-Tech Woodstove, Sheetrock Screws: LOL!
  7. oldAGE

    oldAGE Member

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    OK... Received my new refractory assembly from my dealer yesterday and installed it, cemented some seams, reinstalled the upper fireback, and put everything back together again. Tonight I take a trial run to see what happens... Will my magical mystical overfire conditions be solved? Will I now have $500 sunk into a this stove for no apparent reason and something else is wrong? Will it ever stop snowing here and will the ice covered roads ever clear? Will the Mets ever win another World Series in my lifetime.... All good questions and the answers start coming tonight.

    I will post pictures of my complete removed refractory for second opinions later today. Once again, thanks to those who have been participating in my hell. I am glad that I have everyone here and that my two months without a normally behaving stove may soon be over. By the way, whilst waiting for this part to come from what is apparently the moon, I looked at an F500 Jotul Oslo. Are they truly and really "that simple?"

    AGE
  8. Xpress

    Xpress New Member

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    FWIW,

    I just finished tearing down a 2 yr old Resolute Acclaim and the combustion package looked a bit worse than yours but I was experiencing the same symptoms. A fire I was having a tough time controlling. Even with the damper closed it was having a tough time settling down. I ordered a new one, which of course is also on backorder 5-8 more days I have been told. I am hoping a new combustion package helps but the old one was definitely falling apart and yes, it was held together with three (what appeared to be drywall) screws. One interesting thing about the stove was the air inlet in the bottom of the back wall. It is about 3/4" tall and 2 1/2" long. It looks as though the refractory box seals this intake but I am wondering if this inlet in conjunction with the larger holes being formed in the combustion package was the culprit for the excess draft.

    Please let us know how you fare. I would be very interested in hearing about your experience.
  9. oldAGE

    oldAGE Member

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    Xpress - No problem. That inlet you are talking about in the last of your reply is called the Secondary Air assembly and is meant to help keep the CAT at temp. On the Encore, the bi-metal spring expands when the probe that it is attached too and is inside the refractory (through the back of the stove) gets hot and the little metal damper door closes down. When that probe cools, the bi-metal spring contracts and it draws opened allowing more secondary air for heating the catalytic combustor again. I don't know if the Acclaim has the same setup but if it does, check your probe for wear and tear. You may notice that the refractory assembly sits on a couple of offsets creating an air gap between the refractory and the back-bottom allowing the air to pass into the refractory assembly.

    I am hoping that my refractory was broken down enough that, like you think, secondary air was passing through into the firebox doing two things -- increasing my draft and keeping the box too hot. I expect that flue gases were by-passing the refractory and heading up the chimney creating a vicious cycle. I will be posting a first "draft" (pun intended) tonight. I won't be able to get a good long fire going until this weekend as I am deathly afraid of building a long burn and slow burn condition unless I can spend hours attending to the stove.

    AGE
  10. Xpress

    Xpress New Member

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    Can't wait to hear... My stove has nothing at all covering this orifice. No thermostatic control devices anyway. There is a "ridge" or backbone of cast iron in the shape of a square around the opening that pushes against the combustion package I believe. The interesting thing is though, I cannot burn it long without closing the rear damper to slow the draft.

    Anyway, good luck with yours!
  11. oldAGE

    oldAGE Member

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    Fire is running with very small splits and keeping it around 300 for a bit. Will be adding fuel soon. Here are a few photos of the refractory upon removal. Not horrible but....
    AGE

    Attached Files:

  12. oldAGE

    oldAGE Member

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    Well, the Jury is still out. I goosed it up yesterday a bit and I still don't believe my stove is behaving normally although it seems a bit better than previously reported. What are the chances that I have a bad CAT out of the box????

    After keeping her at about 300 for a couple of hours, I added some very well seasoned splits (stored indoors for over a year) and tempered it with some well seasoned splits taken from outside (zero degrees). Backed down to 1/3 primary air and once again, she climbed through 550. I had a small bed of coals and let her sit there for bit and then engaged the damper. For you Encore CAT owners, with my new refractory and new CAT, I still don't get that little rumble that I used to get. And, although the flames slowed down better than in the past month, I used to get that rumble and my flames would be very low and more blue with minor ignition of gases that created a slow rolling burn every once in awhile. Now, I have tall flames that move slowly and with the primary nearly closed, the stove reached about 600 - 625 and then settled back down again and I adjusted the air to 1/3 opened and she seemed to hold ok. This was with the firebox only about 1/3 - 1/2 filled.

    This weekend, I will start in the early morning and see where it takes me across the course of a day.

    AGE
  13. marc nichols

    marc nichols New Member

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    I'm curious to hear how this ended.

    I recently replaced my near new Encore everburn (junk IMHO) with a 2550 CAT version. It burns much nicer but I still have a control problem. Essentially, the amount and quality of the wood load determins how hot it runs. The controls do little. I cannot throttle it back to 400 with three splits...450-500 perhaps but usually 500+.

    My flue system is likely the problem at 8" x 28 ft. My dealer did install a flue damper but even that has little effect. Very odd.

    I'd like to know how air flows through this stove and if there is anything I can do to better control air into it.
  14. Xpress

    Xpress New Member

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    Marc,

    That sounds like the same problem I have with my Acclaim. Is your chimney Class A? Mine is about 22 ft. and has a very strong draft when heated. It seems at times, if the wood is even a bit too dry the draft overpowers the air control's ability to regulate the fire. I also tried an inline flue damper with little success. I actually removed it shortly after installing it.

    I too am curious to hear how the OP made out.
  15. marc nichols

    marc nichols New Member

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    Class A? Is that double wall? If so, yes, about 15 feef or the @28 foot total length. Seems like a weak draft when cool and a very strong draft when hot. My in-line damper has a hole in the middle. I don't remember how large but probably about 2.5 inches diameter. One would think the system would slow and eventually starve, but it doesn't. I'm considering fitting a 6" pipe which would heat quicker but not carry as much air and I would assume, decrease the upper capacity of the draft. I can't shorten the overall height of the flue.

    I'm sure this flue length worked fine years ago with a non epa stove and total inlet air control.

    Today I am burning compressed sawdust logsn (energy logs), just one at a time. After six hours (I get three hours per log choked completley) stove top is still 500+. Two logs or three moderately dried hardwood splits drives temp over 600 fully choked down and if I'm not careful, well into 700.
  16. oldAGE

    oldAGE Member

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    Hey folks. I wanted to make sure that I had good and adequate data before posting. I am saddened to report that although the new refractory seems to be helping me control my fires better to some degree, I don't believe my problems are solved by any stretch of the imagination. I do believe my combustor is working as my smoke is drastically reduced now.

    Like Marc is posting and like Xpress has indicated his concern (I assume Xpress is a "he"), the behavior of my 2550 is nowhere near where it has been. Started fires slowly, built my ash bed to a reasonable depth, maintained temp with small splits at 550 - 600 with primary air at 1/4. Add a couple of larger splits and let them get going, engage the damper. She holds at 550 as it has in the past.... but, then as the splits begin to get good and charred, the temps rise. I have my original thermometer and bought an inexpensive Rutland brand a month ago. My old one (must tap it to get it to jump to the indicated temp) moves upwards of 650+ while the new Rutland reports 725+... And after a good while it begins to fall off. If I close the primary air, the temps still would remain high and once burned off, she would cool down.

    In the past, following the exact steps above, I would engage the damper at 500 - 600 and set the primary at 1/3 opened and she would sit there at 550 for hours at a time. Closing down the primary would reduce the heat. Again, I do get a tall lazy flame but in the past it would be a low blue flame with rolling waves of yellow flame as the gases ignite. I don't seem to have that behavior any longer.

    Thanks to all and my search for an answer continues.
    AGE
  17. Xpress

    Xpress New Member

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    Sorry for the name...I was staring outside and saw the name brand of my small fishing boat and used that. All other things being equal, it would seem maybe there is a new air leak? Did you regasket the stove just to be safe? Good luck, I know I could use some as well. Please keep us posted.
  18. oldAGE

    oldAGE Member

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    The first thing I did was regasket the doors and ashpan. After than, I regasketed the griddle top. After that, the inside wearplates and lower fireback. So, just about everything that can be gasketed is gasketed. I used furnace cement on the seams that show signs of being brittle. The one thing that I am going to do next is use less seasoned wood along with my seasoned wood to see if I can find a decent middle ground of moisture content.

    AGE
  19. swestall

    swestall Minister of Fire

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    Hey! I am wondering how much of a problem this really is? The temps you are getting are not really out of line with what the stove can handle. The stove is older and since its not new, it isn't going to work as it did when it was out of the box. But, how much more wood are you using and is the stove giving you good heat for the wood.
    I had similar experiences with my Defiant CAT stove when I had it. It just didn't make a lot of difference to me. It wasn't overfiring, it didn't get over 700 unless I got it there and it didn't use any more wood than before. The heat was great!
    In fact, I think I was stupid for changing it out to the non-CAT stove. After that fiasco I upgraded to a Hearthstone Mansfield and am happy with it; but the Defiant CAT was just fine the way it was.

    Perhaps that might be the case with yours; It isn't just like new, but the performance is within its operating limits, it isn't overfiring and you are getting nice heat from it?
  20. oldAGE

    oldAGE Member

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    Swestall -

    I was thinking the same thing when I tested it this weekend. It is just on the cusp of being OK by my standards. I made that comment to my wife yesterday that is seems better. As a matter of fact, I was just speaking with a coworker who helped drive me towards the VC in the first place and he asked the same question. What is bothering me is that after seven years of expected behavior, it is "radically" different than what I was accustomed too which is what is bothering me. The fact that I can't make the stove "cooler" on demand is something that sits in the back of my mind. It seems to operating on its own terms. That's why I want to try a few things still. I really didn't try to get my stove to 750 degrees... It just went there on its own. I am afraid to fill the firebox because I really don't know what to expect. Will more wood just mean less air and it will control itself? I guess only time will tell and I have to try.

    One other note... there seems to be greater slack in my primary air control so its use is not as granular as it used to be. I am going to see what happens if I take some of that up...

    Next, I am going to invest in a fairly inexpensive IR Thermometer to see how hot that device records it to see how accurate the bimetal thermometers are. I was able to put my hand about three feet up my double walled stove pipe so i am wondering how hot everything really is.

    Thanks for the feedback. Keep it coming and keep me honest.
    AGE
  21. swestall

    swestall Minister of Fire

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  22. eernest4

    eernest4 New Member

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    hi old age,

    I think the word you wanted to used to describe the loose opperation of the primary air control was linear , non granular. garnular refers to suger or snow, but we got the idea.

    After seeing all the troubles that you guys get with your catalitic cumbusters & how complicated your stoves are, I am glad that both of mine are secondary burn.

    My friend Billy just bought a vermont castings encore defiant from 1986 all beat for $30.oo
    & of course ,he will want to rebuild it & restore it to its former opperation, not even knowing what that former opperation was like.

    Thats why i am reading this thread, because i know he will be comming to me for help later this summer on that stove.

    well, you are going through hell with it now & I will be going thru the same in oct or nov 2008, depending upon how long Billy waits to get started on it.
    Well , at least, it is mostly his trouble, even if I have to get the step by step & am expected to
    give his rebuilding efforts steering advice & troubleshooting.
  23. marc nichols

    marc nichols New Member

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    I can't image going from the CAT to an everburn. God did I hate that everburn and am I ever happy to have it gone. Howeever, I had the same issue with lack of control so I'm now down to my flue. I suspect that 28' of 8" pipe is just too much for the stoves designed-in controls to handle. Even with a damper, I can't burn three splits at 450....not gonna happen. So, it is impossible to load it for an extended burn.

    I'm going to try a 6" flue and include a damper for good measure. I'm stuck with the 28' parameter. If that doesn't work, I'm going to see if I can modify the air intakes on the stove.

    Billy should be pleased with that older unit. I sure did like my 30 year old VC pre emissions stove. A joy to operate and to look at.
  24. oldAGE

    oldAGE Member

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    Thanks for all the kind words and corrections to semantics. My 8" of SS chimney and 8" of double walled stove pipe worked perfectly well with this stove up until Christmas Day, 2007. Seven wonderful years of great heat, great consumption control, and great temperature control. My issues are something completely different. I'll get to the bottom of it or I will have a Secondary Burn Jotul F400 or F500 in its place by summers end....

    AGE
  25. swestall

    swestall Minister of Fire

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    That is how I solved my VC problems, a new stove. I went for Soapstone but the f500 is nice too.

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