Encore 2550 rebuild... start to finish

[jharkin]

Ok, so the amount of buildup I got in my chimney last year prompted me to take the stove apart and contemplate a minor rebuild.

To set the background:

- Wood supply is good. Last year I was burning 2-3 year CSS wood, mostly oak maple and some crabapple that I cut myself.

- Stove seemed tight last year and was controllable. No obvious signs of leaks and all the door gaskets good.

- I did get weird catalytic behavior. Sluggish light off on big loads, smoke anytime below 1200F probe temp. I run a steelcat and its warped so Im considering sending it back on warranty.

- You can see there is a lot of black creosote in the firebox, but there was nothing but brown ash in the back of the stove past the catalyst and I was getting good 1100F - 1700F catalyst probe temps, once it lit off! - last year. Typically this stove runs with almost no flame in the main firebox when the cat is engaged however, which is I think why I get firebox buildup.

- Longer term I know the best bet with a VC is to replace it. Financially I'm not in a position to do that this year, but am willing to do a modest investment in parts if I can get it to last a couple more seasons.

- This is not our only source of heat. It gets used mostly on weekends only.

Ok, so to start with I did another good sweeping. I did a late season sweep last year and this time I got about 2 coffee cans of crusty black chips. Probably from only a half cord burning. I installed an outside outlet by the new patio so this time I setup the shop vac outside with a long hose through the window. So much cleaner!




Lots of crusty creosote in the box, but so far the interior castings look good.



Lower fireback looks ok, as does the damper and upper fireback. Damper gasket has seen better days but still passes the dollar test.



Here is a summary of the completed project:

https://www.hearth.com/talk/threads/...advice-appreciated.112149/page-8#post-1536832

 

[jharkin]

I had been expecting to find the refractory is shot, but I dont think it looks too bad. Took a look with the mirror and the secondary air thermostat probe looks ok also.


VC experts - does this look ok? Anything look worth replacing?

 

[jharkin]

I pulled the 2 inner side panels. The bolts came out easily (!) Both panels still have gaskets, and there was some soot in the air channels but not enough to cause blockage. The left side panel has creosote glazing inside, and I know that the stove seems to burn hotter on the other end (right).

The right side panel looks very clean inside, as does the thermostat mechanism, which seems to be working fine.

 

[jharkin]

Here are the inner side panels. It looks like not only was the left side cooler, but some of the gasket is crudded up with creosote making me think air was leaking there.

 

[jharkin]

Here are all the parts I removed. Lower fireback needs a new gasket but looks straight. The catalyst hood not surprisingly is warped and will need replacing - but I can still manage to get it to go back in.

I dont see any cracks.

 

[jharkin]

So here is what Im thinking and where I would like some advice.

My catalyst is warped, and it does light off sluggishly. Its a Condar steelcat only 3 1/2 years old so I will send it back for a prorated warranty replacement.

The hood I will replace.

I will do the lower fireback and inner side panel gaskets and put them back. Also have a lot of creosote and soot to vacuum out.

The refractory I think is ok to leave as-is. Anyone disagree ?

The upper fireback I am temped to leave alone since the refractory is ok. I probably should do the damper gasket but it does pass the dollar test and I dont see how to replace it without pulling the upper fireback, or the flue collar. Does this sound ok, or would folks recommend I pull it and re gasket everything since I got it this far?

I did the griddle, door and ashpan gaskets last year. I might do the glass gaskets now.

Anything else I'm missing?

 

[jharkin]

The more I think about, I think I will pull that upper fireback. I might curse the thing putting it back in, but I fear I will curse even more if I dont pull it and still have odd symptoms this winter after everything else is back together.

 

[jharkin]

OK, to answer my own question, I pulled the upper fireback. Bolts came out easy, and halfway out I gave the right one a tap with a mallet to break the cement bond. It was wrenching that casting out that is a $(*&%(&#@@. They tell you to just swing it out to the right, but when you try it feels like its hung up on the top edge. It hangs on a lip around the flue exit and you have to wiggle it forward slowly till it falls free, then pull it out at an angle till the damper handle slides out of its hole. The tricky part is that there is only one spot lined up with the ribs on the right side wall where it fits without bending that rod.


Here it is. A real mess but seems straight and crack free.

 

[jharkin]

And a better look at the refractory box. What do you guys think, should I replace it?

So far I'm into this project for about $250 between a warranty cat replacement, gaskets and misc parts. Replacing the refractory would add another $220 ($475 total). I dont want to do it if I dont have to, but it almost seems like doing a water pump with a timing belt, since you are in there..........

 

[jharkin]

Alright, I'll keep this one going as a log of the rebuild in case it helps anybody in the future.

I starting working on cleaning up the castings, this is going to take the most time of the entire job. The upper fireback is a real piece of work because there is so much furnace cement on it. This stuff is more of a pain to get off than gasket glue. I cleaned it with a wire brush and started chiseling off the big chunks. Neighbors probably think my garage sounds like a blacksmith shop.

Next step will be to use the dremel with a grinder and wire wheel and take all the mating surfaces down to bare metal.




Even more of a pain will be cleaning up the inside of the firebox.

 

[jharkin]

Work continues. Old cat is on its way back to Condar on warranty and I ordered a the hood and a full gasket kit from woodmans. Fedex says a package is on the way but it doesn't sound heavy enough to include the hood... hope its not on long backorder.


In the mean time more work on the castings in prep for new gaskets. Goal here is to get every surface that will get glue or a gasket down to shiny clean metal. First up is the upper fire back. I chiseled off the big chucks with a a hammer and old screwdriver then use a grinding bit in the dremel to get the rest. I'll give the whole thing a once over with the wire brush when done.

I have a lot of respect for professional stove techs who can rebuild an entire cast stove in a day. I probably spent a good hour and a half just on this one casting and its not done yet. 3 more to go after that, and then the real messy job cleaning up the mating surfaces inside the stove.



One thing I haven't decided yet is how to reinstall the upper - gaskets, glue or both. Its got channels for gaskets, but was only cemented in. Doing a search of the forums reveals differing opinions. (This may have been worked on before, previous owners of the stove left a large half used tub of furnace cement behind)

 

[fortuna1]

Thanks for posting this. Keep going!
I sold my Fisher Grandpa and just got one of these stoves ( 2550 ) and it needs gaskets and a cat. Just ordered the cat and a gasket kit from Black Swan. Probably getting to it in a day or two so this is timely.

 

[jharkin]

Thanks for posting this. Keep going!
I sold my Fisher Grandpa and just got one of these stoves ( 2550 ) and it needs gaskets and a cat. Just ordered the cat and a gasket kit from Black Swan. Probably getting to it in a day or two so this is timely.

You are lucky in that the cat is very easy to do -assuming the refractory box is in OK shape and no iron parts warped. Just pop the two iron wedges and pull the lower back. When its open use a mirror to look for the secondary air thermostat probe in the bottom of the refractory box and replace it if its badly deteriorated (easy access through metal cover on back of stove)..

All the gaskets on the moving parts (doors, griddle, etc) and most especially the ash pan have to be pretty much perfect for this stove to work right so take your time and don't rush replacing them all. I ripped out and regasketed my griddle twice a couple years ago before I was satisfied with the result.

Good luck!

 

[fortuna1]

Quick question. Some websites talk about a gasket around the catalytic combuster. Is it needed?

 

[fortuna1]

Also, have you used a catalyst temp sensor? Worth the install?

 

[jharkin]

Quick question. Some websites talk about a gasket around the catalytic combuster. Is it needed?

The gaskets referred to is a mica impregnated expanding gasket tape such as Condar Catguard. Since this stove has a ceramic refractory, you are not supposed to need one. Last year however I found that there was a pretty big gap around mine due to old refractory (almost 1/4") and I decided to use one. Careful though, if the cat is snug in there adding a gasket could deform the refractory.

Also, have you used a catalyst temp sensor? Worth the install?

Yes I do - see the metal rod below where the cat sits in my photo of the refractory. There is a metal button on the back casting you pop off and insert the probe. I use the Condar Digital monitor. Others cook up there own with a k type thermocouple and digital reader - parts available for around $30 through amazon (member Joful posted a sample setup last year).

For this stove I feel the monitor is a must have. Its much easier, and I feel safer, to set the air controls based on catalytic temp (rather than griddle temp alone). Because of the stoves design its possible for the griddle thermometer to be in the safe zone while the catalyst is at overfire temp. Without the monitor your only sign of trouble would be the sight of glowing cast iron through the window (bad!)

With the cat monitor operating the stove is simple:

• Start up a fire and let it burn wide open to warm up the stove
• On a new load you close the damper (bypass) when the probe reads 500F (I go higher on big loads).
• If the cat lights off properly you should see it rise to 1000F+ in 5 min or less, if it climbs slowly and stops around 800 that is a catalyst stall and you need to reopen the damper and heat it up some more then try again. Once the cat is active start closing down the air control in increments till you reach cruising. For me this is with the air between fully closed and 1/3 open, depending on how much heat you want.
• Any time you see the cat probe temp over 1600 you should close the air completely (1700+ is the danger zone)
• In cruising mode the cat temp will normally be in the 1100-1600 range (griddle might be 500-700 depending on how the primary air is set). During this part of the burn the air control will typically be almost closed but the stove is pumping out massive heat from the back casting due to the cat. Probe temp usually will slowly climb through the burn then peak and drop off fast. This part of the burn might be 1-2 hours for a couple splits or as much as 4-6 hours on a full packed load of Oak.
• Once the probe temp peaks and starts falling s you know the major out gassing phase of the burn is done. You still have hours of usable heat in the coals and at this point you can safely open up the air control to maintain griddle temp without fear of overheating the catalyst.
• Once the cat temp falls below 800 with the air control open the load is pretty much burned out and its time to reload.

rinse & repeat...

 

[jharkin]

Work continues. Old cat is on its way back to Condar on warranty and I ordered a the hood and a full gasket kit from woodmans. Fedex says a package is on the way but it doesn't sound heavy enough to include the hood... hope its not on long backorder.

No suprise, got an email from Woodmans that the combustion throat is on back order. Will have to call them and find out what the ETA is. Worse case I think the existing one will still fit back in, maybe with a little grinding.. Bigger question is can they get the refractory if I decide I need it.

 

[Defiant]

I have been getting my parts here http://www.fergusonfireplace.com/
They are very helpful, I got my refractory there and I find their prices cheaper than Woodmans.

Now that you have gone that far I would go for the new refractory package and check out your secondary air probe. Looks like you are doing a great job. One thing I do when reinstalling the damper assembly is lay the stove on it's back on blocks. It makes it easier to line up. I will be doing mine this week if you need any photos of the aforementioned position.

 

[jharkin]

I have been getting my parts here (broken link removed to http://www.fergusonfireplace.com/ferfirpartslookuppage.html)
They are very helpful, I got my refractory there and I find their prices cheaper than Woodmans.

Now that you have gone that far I would go for the new refractory package and check out your secondary air probe. Looks like you are doing a great job. One thing I do when reinstalling the damper assembly is lay the stove on it's back on blocks. It makes it easier to line up. I will be doing mine this week if you need any photos of the aforementioned position.

Thanks I will give them a call and look at ordering a refractory. The secondary probe I changed 3 years ago and looks ok to reinstall. (BTW I noticed that Black Swan and Stove Parts Unlimited are also out of stock of everything... hope there inst a part shortage related to the buyout)

I would certainly like to see photos of how you do it. So far I'm just working on the stove in place on the hearth. How is it to lie the beast down - a doable 2 man job? I'm guessing with all the guts out and door/griddle off the shell still weighs close to 300lb?

Oh and last question for you - do you cement or gasket the upper in? Mine was cemented but it looks like you could gasket the sides for sure and maybe even the top flange. The 5927 fireback kit instructions that Im using as an assembly guide just say bolt it in.

 

[Defiant]

I tilt the stove myself, it is very light with all the innards out, I use a double 6 x 6 blocks to lay it on, I'll submit photos when I get there, much easier to work on out of the fireplace, lay out a drop cloth to work on it. I gasket the sides and put a bead across the top flange before bolting together.

 

[jharkin]

A bit more every day. Upper back is almost ready for new gaskets, and looks in remarkably good shape once all the old cement and baked on soot is cleaned off.

 

[Reckless]

I have some questions being that I have this same PIA. Is the damper assembly only held in by furnace cement? Is there a way to replace the damper gasket without removing the complete assembly? I should just say screw this 30 y/o VC and get a new stove already.

 

[jharkin]

I have some questions being that I have this same PIA. Is the damper assembly only held in by furnace cement? Is there a way to replace the damper gasket without removing the complete assembly? I should just say screw this 30 y/o VC and get a new stove already.

What model stove do you have? This one was only made since the mid 90s, and to do the damper gasket you either have to pull the upper like I did, or take off the flue collar and try to work from inside the back. Older Encores like the 0028 and 2140 I believe had the gasket on the damper plate itself and could be replaced from inside the stove assuming you can reach in there. The older ones also had a larger upper fire back held in by 4 bolts.

 

[Reckless]

What model stove do you have? This one was only made since the mid 90s, and to do the damper gasket you either have to pull the upper like I did, or take off the flue collar and try to work from inside the back. Older Encores like the 0028 and 2140 I believe had the gasket on the damper plate itself and could be replaced from inside the stove assuming you can reach in there. The older ones also had a larger upper fire back held in by 4 bolts.

Its a 2550 but the original owner NEVER took care of it, so it only seems like 30 years old...... The flue collar is gasket rope or? And it still looks like it will be tough even that direction. Maybe Ill just put up with cold mornings and rough it out till I get a new stove :/

 

[jharkin]

Gotcha. The flue collar is gasketed. I agree it looks tough but suposedly is doable to get the damper that way.

If you do it the way I am you do have to half gut the stove, and if anything is warped or a bolt breaks it might get expensive. You can use the instructions for the fire back kit as a guide. Probably not worth it if you are set on replacing it in a year or so, I'm hoping to get at least 3-5 more from mine.

https://www.google.com/url?sa=t&rct...9Kl4ohro7CxK1PVwVCuj5SA&bvm=bv.50768961,d.aWc