Encore 2550 rebuild... start to finish

[jharkin]

Ok so I found some time on the weekend between yard work and car work/ oil changes to start the final interior cleanup. I got most of the loose buildup off already, now the goal is to remove all the remnants of furnace cement from the upper fireback mounting surfaces and clean it down to bare metal so the new one will fit and seal right.

Plan will be to dry fit the upper fireback into place before installing the refractory or gasketing. I figure once that's all done I have only one shot to get it right if I'm cementing it.



As with previous jobs, a dremel with a variety of grinding tips is almost a mandatory tool for this work. I put the shopvac outside with a long hose coming through the window and work two handed holding the dremel in my right and the vac hose in my left. Don't forget the mask and goggles too.



A couple findings...

First off, the lip at the top of the back sating that the top edge of the upper fireback hangs off is actually a half round groove like a gasket channel. Defiant, I know you stated before that you gasket the sides of the upper and glue the top edge? Or could I put a gasket in this top groove and avoid cementing it in?

Secondly a lot of the cement in the vertical seams between the back and sides was loose and falling out. If i had the luxury of time it probably would not have hurt to take this stove out of the house and break it down all the way but I cant start into that now. The back casting actually has a 1" flat overlap on the side panels with what looks like a double tongue and groove seal so I'm hoping this is not critical. I will grind all the loose cement out of the channel and lay in a new bead of furnace cement from the inside as insurance however. Not ideal but better than leaving it as is.

 

[jharkin]

And got everything cleanup up nice for the new refractory to fit.

 

[jharkin]

We are getting really close to the goal line now.

All the painting is done. I even painted the stove pipe stub and tee for good measure.

I did a test dry fit of the upper fireback. Now that I had cleaned out all the buildup and old furnace cement it actually went in very easy! Luckily not the swearing fest BBar had to go through on his 0028 - so I guess there was some logic in the design change by Vermont.


Next up I need to touch up the internal seams with furnace cement and install the refractory. Then gasket the sides of the upper, then run a bead of furnace cement on the top channel inside of hte back casting and bolt hte upper in.

Once that's done the rest of it should be not more than an hours work and we are ready to rock.

 

[jharkin]

Ok, making some more progress finally. I was on hold for a bit with my parents coming up to visit the grandkids over the weekend and a lot of yardwork.

Its also hard to do any work on the stove after work since the kids go to bed at 7pm...

First off time to fuel up for the home stretch... relieved the local of their last supplies of Oktober'




And finally got around to removing that unnecessary pipe damper. Should have done it 4 years ago since my pipe is close to minimum, but its a lot easier to do with the stove guts out. (Now I just need a couple stainless 1/4 sheetmetal screws to cap the holes in the pipe)



Hopefully that will help shoulder season draft.

 

[jharkin]

Then I finished up the last gasket jobs.



And finally did the last of the cleanup inside the firebox and touched up those rough seams with cement. No gasket glue this time, real 2100F furnace cement - once it hardens I'll grind off the excess that got smeared around.



Yeah, I know, I cant be sure of those seams if I dont break the stove down completely but I just dont want to tackle that in October. As best I can tell the cement down in the T&G is still there its just the excess that squeezed out that's crumbling. Anyway I'm going to try it this way and if its trouble the entire stove will come apart next summer.

 

[jharkin]

And one last minor fix. The left side door has always rubbed on closing. Turns out the door air manifold was bumping the opening. 20 second with the dremel fixed that and she is smooth as silk now

Have I mentioned yet how indispensable a dremel is for this rebuild job?

Having a real hard time getting the doors adjusted. I can see into the stove on the bottom left door where the glass screw mount passes the right door. Any suggestions? I can post pics if needed.

Reckless - note this photo for the gasket routing on the left door....

 

[jharkin]

Next step is to place the refractory, install cat and secondary probe, then cement/bolt in the upper fireback. After that the rest of the panels, grate and andirons just bolt in. Should be down to only an hour or two work left!

 

[jharkin]

Ok, so we are almost there. I dry fit the upper fireback one more time, this time with side gaskets and bolts, to do a final fit check and check the operation of the damper. It was a bit tight but some work with the adjuster screw and a lot of graphite spray on the moving parts did the trick.

Then the fireback comes out, refractory goes in, and the two stainless sheetmetal heat shields. I laid a thick bead of cement on the upper groove inside the stove and put the fireback back in. Its a good idea to wait till you are ready for the final assembly to place the refractory, as the back of the fireback has a beveled/chisel edge that compresses the refractory opening slightly to make a gas tight seal.

Once its in tight, the side panels go in with a little encouragement from a rubber mallet and get bolted down. New hardware and copper antiseze everywhere.



Then use a small twist drill turned by hand to make pilot hoes for the secondary probe and cat temperature probe, install and hook up the secondary air (I get some closeup shots of the back tomorrow) and install the new catalyst. Its a tight friction fit.



BTW, those drywall screws that everyone loves to make jokes about in the VC refractory box where just there to hold it while the glue dries. That front panel is bonded to the box with refractory cement.

 

[jharkin]

Oh $&%#%#%$%$&#


I knew this was going too easy.

So we have a problem. When I put in the upper fire back, in the prcess of manhandling it into place the refractory box got tilted to the left about 1/4 inch.

The refractory box is sealed to the upper back well. Its not far enough out to cause any problems getting the lower to seat properly.
However it is tilted enough that the bottom of the box is not tight to the secondary air channel ribs, which means secondary air meant to feed the cat would leak right up the flue.

Even worse I only noticed after the cement on the upper hardened and I already made the secondary probe hole.


So I have two options:

1 take it all apart, grind off all the non cured cement again, patch the secondary probe hole, replace it all and do it over.

Or

2 Cut off a piece of the old refractory to stuff into the gap at the base and seal the secondary air channel.

Second choice is obviously a lot easier and I think would work just fine. I fear trying to rip it all apart and do it right I might just make it worse. Thoughts?

 

[jharkin]

Some close up shots. I am SOOOOOOOOO pissed off at myself. Ive been very careful all along and then I got careless with this part.





I thought about it overnight. I'm thinking now I should take it apart and redo it right. I could probably patch it and make it work, but long term who knows how well it will hold up.... and it will always bug me. Its just the thought of haivng to pry and break that upper back loose again and grinding off all the half cured cement (which actually seems worse than removing the hardened stuff).

If I do, I will mix up a little bit of furnace cement and crumbled up refractory to make a paste to seal up the old probe hole, and Ill use a couple dabs of furnace cement to glue the box in place tight before I put in the upper so it wont move again.


Defiant what do you think?



rrrrrr !

 

[Reckless]

Wow Jeremy Im sorry to hear that man. You're talking at least another 3 hours of work no? What caused that to happen and how can I avoid it when I do my rebuild?

 

[jharkin]

Yeah, probably a couple hours. I need to undo the bolts and pry the upper fireback to break loose the cement bond at the top, wiggle it out (should be easier this time without all the excess cement and creosote buildup around it), then use the dremel to grind off the fresh cement, and put it back in.

What caused it? The refractory box just sits in place. The back side of the upper firebox has a beveled edge that presses into the opening of the box, slightly crushing it to make a gas tight seal and also hold the box in place by a press fit. Now the way you put the upper in is you first slide the left side and damper rod into place and then swing the right side in and up - in that motion to push it up onto place it probably grabbed at the edge of the box and dragged it.

Now its in there so tight there is no way Im going to coax it back into its proper location without removing the upper. UGH.

 

[Defiant]

Sorry to here that Jeremy, the photos show why I lay my stove on it's back raised up so I can lay the upper fireback in and bolt. I hope to have mine done this Sunday.

 

[jharkin]

Thanks D.

So anyway I answered my own question - took it apart before work. It only took 15 minutes to pull everything out, and in the process I found that the top edge of the upper wasn't fully bonded to the cement as well - probably didn't put a thick enough bead down. Probably a good idea to redo it. Filling the probe hole will be easy actually, just cut a small wedge of refractory and stuff it.

I also noticed that the thermostat cable looks stretch out, as if I got it bound when I clamped in the right side panel. So good opportunity to adjust it, and fix the refractory and upper seal properly.

I'm now guessing that this will end up being an under 2 hour setback.

 

[jharkin]

the photos show why I lay my stove on it's back raised up so I can lay the upper fireback in and bolt.

Drrrr yup its quite obvious now - you can reach into the flue collar and hold the refractory in place! genius.

 

[Defiant]

Drrrr yup its quite obvious now - you can reach into the flue collar and hold the refractory in place! genius.

Found this to be the best way, gravity holds the upper fireback in place.
Good Luck, it's better to find these things out before you burn it.

 

[jharkin]

Thanks. I have no doubt that I can get it right, its just a pain in my backside

My target all along was to do the break in burns the week of colombus day (I have vacation). I should still be able to hit that if I dont screw up anything else.......

 

[jharkin]

Looking at it some more, I see that the upper back didnt seal to the bead of cement I laid into the channel (about 1/4") because with the gaskets on the side it didnt bottom out in that groove. Maybe it is better to just cement it all?

 

[jharkin]

Drumroll please....

The rebuild is done! I will elaborate later with more pictures, spending quality time with two sick toddlers right now

 

[jharkin]

OK, so after we met last, I disassembled everything and ground off all the old cement. Then I cleaned up and regasketed the upper again.



Now I got the refractory box into place again. This time I notices that when pressed back tight at the top it could wiggle a bit at the bottom. I know the older models used kaowool strips to seal everything, the 2550 just relies on a tight press fit of the fireback. I want this thing sealed tight, so I used what I had and cut up some strips of condar catguard expanding gasket to hold it in place during assembly (not too much, dont want to crush the box.

Also cleaned up and places the 2 stainless heat shields. These are critical - dont leave them out. Its the only thing protecting the sides of the back casting from the direct blast of catalyst exhaust at up to 1,700F.

 

[jharkin]

Now I put a good bead of cement in the upper channel again, this time abuot a half inch bead! so that I know I will get a good bond. The upper back goes in on the left, get the damper rod through the hole then swing the right up into place. This time I held the refractory down with one hand while lifting it with the other, and only once in place reach behind the stove to start the bolts. once its lightly bolted, check that the refractory is in position onle last time and make sure the damper rod moves freely then crank the bolts down.




I know I used enough cement this time because it squeezed out of the joint inside. Reach in with a finger and smooth it out and remove excess like you are doing a caulk job. Should be good and air tight.

The rebuild notes say the bolts should be snug, not tight. I will leave them tight till the cement cures than back out and re-snug.

A liberal coating of CRC spray graphite on the damper rod at all the moving points makes it work smoooth as butter

 

[jharkin]

Put in the secondary probe, cat temp probe, catalyst, catalyst acess panel, bolt in the side panels (checking the thermostat cable is clear this time), pace the lower fireback and hammer in the wedges, place the hood, replace the ash grate, and bolt in the andirons.

 

[jharkin]

Forgot the warming shelf this morning. Thats done now.



Lookin' good, eh?

 

[jharkin]

Before and after:



Another




BeGreen or Web, you guys can change the title now to "Encore 2550 Rebuild - Complete" I'll update in a couple weeks with first fire shots.

 

[Defiant]

Never got to mine today, have a fire going in it's place