Encore 2190 Fireback

[postandbeam]

I've searched a lot of posting about this stove, and if this post is redundant, then I will welcome a ruler slap to the back of the hand, and a link to the previous conversation.
I'm rebuilding the back of my 2190 and have torn it apart, to find the culprit preventing me from putting a replacement combustion throat piece back in properly. The arms of the sides of the new throat piece will not line back up, and there is some warping of the upper fireback, which looks to comprise of the damper assembly. I am trying to ascertain how much of both the upper and potentially the lower fireback I will need to replace. The stove has been great for the few years I've owned it, its a 1993 model with cat, that I would like to breathe a little life into. Thanks.
Bill

 

[treefrog25]

Hi,

I also have a VC Defiant Encore model 2190 and am doing pre season maintenance.
Last year the combustion throat became so warped that it would fall out easily. I ordered
a new one from Blackswan but like you I have discovered that due to warpage of the surrounding
components: lower fireback + upper fireback, the new throat cover cannot be installed.

Initially, I thought that I would have to buy a new lower fireback. The lower fireback has two vertical
ridges that fit on the inside of the throat cover. Due to warpage, these ridges now, no longer fit inside
the throat cover. To resolve this, I used an angle grinder and cut/ground off the top 2" of these
ridges. Next, I replaced the lower fireback in the stove and tried to install the throat cover but
now I see that the *upper fireback* has sagged/warped and I am about 1/4" short of being able to
put the throat cover peg over the holding ledge.

Possible next steps:
1) Grind down the center top of the combustion throat 1/8-1/4" in a slight arc so that it matches the sag
of the upper fireback and will be able to fit into place.
..or...
2) Remove/replace the upper fireback. I have tried to remove it just to evaluate its condition and remove
one of the broken bolts. However after removing the 2 bolts I didn't come free and I posted a question on this
forum seeking advice on how to get it off.

As I see this stove VC-2190-w/cat maintenance issue, it appears that component warpage is a fact of life.
If I can fit the pieces together AND the stove remains *airtight*, then warpage should not matter. For
example, my ash grate is warped up 3/4" in the center, but that shouldn't affect anything, the ashes will
still fall through. Ditto for the lower fireback. Now in the case of the previous combustion throat, I replaced
it because it is so warped that it would not function properly and fell out repeatedly.

FYI, there is a 'Service Manual' for the similar but different model 2140 (no cat?) at: https://www.hearth.com/econtent/index.php/wiki/File:Serv_Encore_0028_2140.pdf/

Tim

 

[postandbeam]

Tim,
I looked at mine again over the weekend, and it sounds like we have similar issues. My lower fireback is the lesser of evils, my upper fireback has experienced more warping, and it droops down. I thought about doing some grinding myself, but I'm more inclined to buy the replacement parts instead. Did you find that you'll need to do any more maintenance over and above the upper and lower fireback to get the throat cover to fit? Thanks.
Bill

 

[treefrog25]

Hi Bill,

At this point I am still into the analysis of the situation. I still have not gotten the upper fireback off, I've been hitting the broken stud (it sticks out 2") with
PB Blaster every 12 hours. When that comes off I should be able to see what it needs, but if I can get by year to year by 'adjusting' the fit of these components,
I will . Its clear that I could put $500 into the stove for all new innards:
refractory box
lower fireback
upper fireback
ash grate
But as these components have structural integrity, I'll try to get more life out of them.

Tim

 

[postandbeam]

Tim,
Thanks for the reply. I agree that there is still plenty of integrity in the pieces, even with some warping. My concern last winter was running the stove without the throat lid in place, which allowed the flames to go directly into the rear area, and I was concerned about damaging my cat. The cat looks good for now, it will likely need replacing next year. One of my refractory pieces broke in two, but its all still there, so I'm hoping to get one more year out of that as well.
Specifically regarding the upper fireback, are there only two bolts holding this unit in place? I am going to buy a new upper fireback with the damper built in this week, but need to understand how to take the old one off? Thanks.
Bill

 

[phishheadmi]

Hey Tim and Bill,

Just thought I'd check in to see how everything's going with your stoves and ask a quick question. I'm stuck the same place Bill was a while back, with trying to remove the upper fireback assembly. BOTH my hex bolts on the back have snapped heads, but the one on the left seems loose, it's snapped off below flush and seems like it might just pull through, the other is solid. Are these bolts threaded through the outside casing or do they just pass through and thread into the upper firebox? I guess what I'm asking is: do I really need to pull remove those bolts or can I just pull them through with the upper fireback? Once I get this out, I think I'm smooth sailing...have both the new upper and lower, refractory package, cat, throat hood, etc. I'll probably replace the gaskets while I have the beast torn apart, but other that that I should be ready to rock!

Thanks,
Matt

 

[postandbeam]

Matt,
I did finally get my new upper fireback in place, and I don't believe that there is any threads in the exterior stove casing, the bolts only thread into the back of the upper fireback. I will say that when I did get mine loose, it was something of a bear to gently lower, and get out of the front doors. I would recommend taking off the rear housing for the stove pipe in the back, remove the griddle, and the front doors, so its wide open for you. I had someone stand behind the stove and reach through the top and hold the weight of the upper fireback, while I layed in front of the doors to lower it once it was loose. Putting the new upper fireback in was a bit of a struggle as well, it took a while to line up the bolts, but we eventually got it all in. My only mistake was putting the damper handle back together upside down, and then it wouldn't lock the damper shut. But a few beers, and some patient attempts, and a few more beers, and it all came together as it should. I did replace all my gaskets while I had it all open, and once I get my sides and lower fireback in, I'm hoping for a burn this weekend. I did talk to my local VC dealer about a replacement cat and refractory, mine is o.k., but will need to be replaced in the next year or two. I was quoted around $725.00 for the cat and refractory, just blows my mind how expensive these parts are. The repair tech at the VC dealer has been working on VC stoves for about 30 years, and he lamented that so many people are throwing away good VC stoves, 10-15 years old, because the parts are so cost prohibitive. I read a post recently, someone posted about building their own refractory's, and I'm thinking we might benefit from looking into this further. There has to be at least a dozen folks out there with Encore's that need refractory's and I have to believe we could build them for a fraction of the price they are retailing for. Any thoughts?????
Bill

"DIY VC Encore refractory assembly and heat exchanger?" is the thread I was referencing...

 

[phishheadmi]

Bill,

Thanks for the advice and words of encouragement! I have everything off the stove and she's wide open, I hope to get that upper fireback out tonight and get started on the rebuild. I read the inside right and left walls are gasketed, did you replace those? Do you know if that's something that needs to be replaced frequently or are they good for a long time as there's no real movement there? As for the cost of parts, they're definitely very high, but you really have to shop around. I must've called close to 20 dealers before I found someone who could get me the fireback kit I learned about on these forums. For a total of $690 including shipping, Hearth and Stove in Philadelphia sent me the entire fireback kit (upper and lower firebacks, throat hood, refractory assembly, probe, etc.) and a catalytic combustor ($490 for the kit, $180 for the cat). For those parts locally I would have been looking at nearly $1,000. I know that dosen't help much when you just need the refractory though...I sure don't see why someone couldn't build one of these themselves, there dosen't seem to be much to the thing...I'd imagine getting the material would be the biggest challenge.

Oh, by the way, I don't really know if my cat's bad, it didn't look too beat up but I don't want to have to tear everything apart again, so I'm just putting the new one in. What should I look for to determine if the old cat's still good? Also, since the heads were busted off the hex nuts for the upper fireback, I have no washers. What kind of washers did you use, just standard steel or something specific?

Thanks again...good luck getting that stove fired soon!

 

[postandbeam]

Glad to hear you are making good progress, its such a good stove, that I haven't hesitated in putting some money into it, because the return on the investment will be very good over time. Plus the sand color matches the trim in my house, and the wife just loves that, almost as much as the heat I think! I didn't replace the sides, just new gaskets, mine weren't all that bad, and I expect they should remain that way unless I overheat it. And that I think is one of the most important things for me to do now that the stove is rebuilt. I purchased a new thermometer, and I am going to faithfully follow the temps, and not allow this stove to overheat, I really think that is the source of most problems. I think if your honeycomb is still in place in your cat, and the metal band is still holding it together, it can continue to do its job. Mine is showing a few signs of wear, but still not gone yet, that's next years project! I agree about making the refractory's, the url to the post I referenced actually talked about finding the material as well, but it would take a number of folks to band together to make it cost effective, but still a very interesting idea......I was able to reuse my washers, but I expect anything would work, there isn't too much heat behind the upper fireback. But I did buy stainless steel replacement bolts and used them in the new fireback, I don't want to deal with cheap bolts again if I have to take it out in the future, a small price to pay for two very important bolts.

 

[treefrog25]

Hey Guys,

My progress on rebuilding my VC Defiant Encore has been slow and steady.
The problem with the stove seems to be that all the parts in the back warp.
But, this is caused by over heating which seems to be caused by air leaks.
So, the #1 maintenance issue is preventing air leaks:
- around the glass
- main doors
- ash door
- primary air flap doesnt shut 100%
- top door
- secondary air flap ... it is open 1/4" with a new probe, I guess its supposed to be like that, do you notice this ??

After my stove burned for 10 years, I had an air leak and it over heated. The combustion
throat was ruined but the upper & lower fireback were also distorted.
I bought a new combustion throat and ground it to fit the slightly sagged upper fireback.
This is a temporary repair. I really need the entire fireback kit. I ordered the refractory
and lower fireback from a dealer in CT, but the suggestion to contact the dealer in Philadelphia for the
fireback kit is great. That is a much better price than I got.

My upper fireback had one broken mounting bolt (goes out the back) and another bolt broke which hold
the actuator rod in place. Neither of these could I remove with e-z outs etc. Instead I got an oversized
drill & tap set at Sears and that worked really well. The larger size bolt is stronger too.

After, a test burn, very hot, I noticed that I could not control the temperature entirely. So, just today,
I slackened the wire to the primary air flap so that it closes 100%, I can hear it slap closed. Next I replaced
all the gaskets on the doors / glass / ash door / griddle.
My next test burn will try to see if now I have complete control of the combustion air. If not then I suspect
that the hole at the broken upper corner of the refractory box may be causing the some of the problems.

Yes, I would be interested in DIY refractory boxes. Potters make kilns from ' which is essentially the
same stuff - white ceramic blanket. But the kaowool I have seen is much softer and not as rigid. I wonder if
it was soaked in some sort of solution which contained glaze chemicals, then fired in a kiln....would it form a rigid
box. I'll have to ask my potter friends about this.

Tim

 

[slindo]

I was the one who started the DIY refractory box thread. Before I installed my new box, I showed it to a friend who is a glassblowing kiln guru, and very familiar with refractory products. and we figured it could be done using fiberfax batts hardened with colloidial silicate, but it would require a pretty elaborate mold. The VC box appears to be cast, not made up of board as I first thought. but out of a very mushy, soft material - my cat was much too tight a fit in the box, a common problem I am told, so I had to trim it, and it cut like butter with a dull blade. I am toying with the idea now of a simplied refractory box, made out of a heavier, more durable material, more like firebrick than mushboard, and eliminating the SS "heat exchanger". It think suspending the cat half on the ceramic box and half on the SS heat exchanger may promote and other problems, due to the uneven rates of expansion. This would probably reduce temperatures at the cat and in the box, which would lower efficiency, but on a hot burning stove used for serious heating probably wouldn't matter too much, and would greatly extend life - I think the inside of the stove is way overdesigned, when you compare it with other cat stoves that just have the cat on a metal plate over the firebox, or even in a box on the stovepipe!

I also wonder whether there might not be quality problems with the refractory boxes VC has been supplying. Our first one lasted about 15 years, and the second on only 5 despite being much more careful. ! But hard to find out with the company always in turmoil.

BTW, a mistake many people make when the do the fireback is not replacing all the seals all over the stove - often the reason they fail is overheating as the seals get older and leakier, so unless you reseal the stove the new one won't last long either.

Yes, I would be interested in DIY refractory boxes. Potters make kilns from ' which is essentially the
same stuff - white ceramic blanket. But the kaowool I have seen is much softer and not as rigid. I wonder if
it was soaked in some sort of solution which contained glaze chemicals, then fired in a kiln....would it form a rigid
box. I'll have to ask my potter friends about this.

Tim

 

[treefrog25]

Hi,

I wonder if it would be possible to construct the refractory box/cat holder from those insulating firebricks which
potters and glass people use to build kilns. These bricks are easily cut and shaved with steel tools. I know you can
get them in various temperature grades and perhaps different sizes as well. The standard brick size is most common
but I have seen that stuff in different sizes too. The price is much less than the kaowool stuff. If this is possible and
even if it only lasted 5 years, it may be a viable solution to the $300 price that VC is charging this year. Next year it may be and additional 5%.

Can you tell me if the secondary air vent should normally be open a 1/4" when the stove is cold? I only have my stove
to go by. Since this secondary air vent is always open at least little bit, there is no way to stop air from entering the stove. However, what I dont know, is whether the air from the secondary air port will affect combustion, perhaps not since it is behind the lower fireback. From my limited viewpoint, if the ash door + griddle+ primary air door + main doors(including glass) are all tight then there *should* be no leaks. In a perfect/new stove can the fire be extinguished or severly limited by the closing of the primary air door?

I did the 'slip-of-paper' test on the gaskets in the main doors + ash door + griddle and got them all pretty snug.
The back side of the griddle is perhaps the least tight but besides putting in a new gasket (which I did) there doesnt
seem to be much I can do to get that seal tighter. Perhaps I could braze a line on the back of the griddle to build it
up then file it smooth to get a tighter seal - it may come to this. But again I would appreciate hearing from others about
the conditions of the various gaskets when tested with the pulling-slip-of-paper test. I wonder how a new stove performs.

Tim

 

[treefrog25]

Hello again,

After my re-gasketing and adjustments to the Vermont Casting Definant Encore '2190', here are my results:

1. the fire was built up with 1 - 2" wood and with a digital probe thermometer, the after catalytic convertor temperature
read 1600 F.

2. The primary air control was pushed all the way back which closed the air shutter 100%.
15 minutes later, the after-cat temperature read 1200F (400 degree drop).
This is now the sort of temperature control that will allow me to prevent it from overheating.

Lessons learned so far:
1. Air leaks are very very subtle but very very damaging to the stove and can/will cause expenisve repairs.
What I realized too late is that even something as simple as a 'drooping' window gasket will allow too much air
into the stove and consequently allow the stove to overheat.

2. Just because gaskets visually *look* ok, doesnt mean they are. I should have re-gasketed my doors and ash-door and
windows years before I did. The maintenance requirement of this stove is not huge but it is real but its also
deceptive and easy to assume that all is well.

3. The secondary air door is closed when the catalytic converter is hot.

4. tbd ;-)

Tim

 

[treefrog25]

A google search turned up LOTs of companies selling refractory materials which could be used for a VC combustion chamber.

Possible alternatives for a DIY refractory box are:

Build it from 1/2" ceramic fiber board as mentioned by Slindo. These are also called combustion chambers and this company specializes in the stuff
http://www.rsifibre.com/index.html


Form/cast it with this stuff:
http://cgi.ebay.com/Kast-O-Lite-30-...Z1267QQcmdZViewItemQQ_trksidZp1742.m153.l1262

Carve, shape and build up the box from soft insulating firebrick
http://www.axner.com/axner/equipment/insulating-firebrick.php
http://www.insulatingfirebrick.com/shapes.html