To the basement, or to the scrapyard? My attempt to resurrect a Tarm Excel 2200 Wood Gasification boiler

[kenmbz]

I have a Tarm wood/oil burner with internal 40 gallon HW and house heat.

I have the original manuals somewhere if you need a copy.
Thing is a beast, I only use the oil side now, but with cost of oil going up it may push me to use wood.
Mine is pretty clean right now. But needs to be a bit more cleaned soon.

 

[aczlan]

Took it outside and rinsed it out with a hose, got enough out for now to work on it without getting covered in ash, will pressure wash things later.
Inside the firebox:

More to the front of the firebox:

Down below:

Where I washed out out:

I now have a box fan sitting on the cleanout opening pushing air through to push the "loose water" out.
Before I go to bed, I will put the heater in the bottom and hopefully finally start to dry everything out.

Aaron Z

 

[aczlan]

I have a Tarm wood/oil burner with internal 40 gallon HW and house heat.

I have the original manuals somewhere if you need a copy.
Thing is a beast, I only use the oil side now, but with cost of oil going up it may push me to use wood.
Mine is pretty clean right now. But needs to be a bit more cleaned soon.

Thanks for the offer, this came with the original manual and I have a PDF copy of it as well.

Aaron Z

 

[5030]

To tell you the truth, if it was mine (wish it was), I'd soda blast the inside and get rid of all the crud. Soda blasting, unlike sand blasting don't remove any metal at all, just crud. Guess I have to stick with my biomass stoves, oh well...

 

[TimberFarm]

That is completely out of character for that bottom burner chamber to have all that creosote in there.
That is the hottest area of the boiler. With good dry oak and a demand for heat the flames coming in the rounded burn area would almost be all blue.
Maybe just because you washed it, but it looks like the sides down there are even creosoted. Be interested to see after it all dries out.

 

[aczlan]

That is completely out of character for that bottom burner chamber to have all that creosote in there.
That is the hottest area of the boiler. With good dry oak and a demand for heat the flames coming in the rounded burn area would almost be all blue.
Maybe just because you washed it, but it looks like the sides down there are even creosoted. Be interested to see after it all dries out.

Pretty sure that they are creosoted, I think that's because it was not burning properly due to ash blocking things (especially the tubes in the back where the smoke is supposed to exit).

Had a conversation with my neighbor (who has run/maintained steam boilers for years at work) and he suggested when I'm ready to fully dry it out and/or to finish curing refractory cement to stick a salamander heater in the opening where you would load wood and let that run for an hour or so, let it cool off and repeat.
That should get it up to a couple hundred degrees, let me get the first couple of stages of curing the refractory cement taken care of in a controllable fashion (without having to fill it with water and try and run it slowly without having it hooked up to the house).
That should also let me finish drying out whatever water has been absorbed into the fire bricks in a controlled fashion.

Aaron Z

 

[5030]

If you get frustrated with it, I'll be happy to come and get it....

 

[aczlan]

If you get frustrated with it, I'll be happy to come and get it....

You will get the first call if it comes to that.

Got the back wall cleaned off tonight:

Surface rust, but it doesn't look bad. No significant pitting or erosion that I could find.

Started cleaning off the door (so it doesn't put creosote on my arm all the time) and it is the rusty mess that I was expecting the back wall to be:

Going to have to replace the insulation and the round vent adjuster as it is rusted through.

Snapped off my first bolt (lower left on the door), will weld a nut to it and see if it comes out.
If not, I will center punch, drill and try not to snap off an extractor in it.

Aaron Z

 

[5030]

Soak it down with either PBlaster or a mix of ATF and acetone and let it sit for a while before trying to remove it. Little heat helps too. I see you need a new door gasket too. TSC will have that most likely in stock. Comes in various lengths. Whomever had it really neglected it but I'll still come and get it if you decide not to restore it...

 

[TimberFarm]

The model I had, which I can't remember right now, did not have steel plates on the doors. They were each covered with a masonry piece. The bottom door had a pyrex sight glass in it that let you see how the fire was burning which it looks like you have too.

 

[aczlan]

Soak it down with either PBlaster or a mix of ATF and acetone and let it sit for a while before trying to remove it. Little heat helps too. I see you need a new door gasket too. TSC will have that most likely in stock. Comes in various lengths. Whomever had it really neglected it but I'll still come and get it if you decide not to restore it...

Given how eroded that one was, I don't know that it would have helped. Has PB blaster on it now.
Actually picked up rope gasket the other day, was 50% off at Lowe's #score.

The model I had, which I can't remember right now, did not have steel plates on the doors. They were each covered with a masonry piece. The bottom door had a pyrex sight glass in it that let you see how the fire was burning which it looks like you have too.

This has a 1/4" steel plate on the top door and masonry on the bottom with a sight glass (I assume something like Pyrex)
It had some kind of insulation behind the steel plate on thebuoper door and everything behind the insulation is rusted and corroded.

Aaron Z

 

[mikester]

If you try talking with your insurance first you will never buy anything. Tell them you are doing your own uncertified repairs on heating appliances and watch your coverage disappear...and good luck getting off the black list

 

[5030]

Maybe in Canada but not here in Michigan. Our insurance carrier knows we heat with biomass and there in no issue so long as the biomass appliance is Warnock-Hershey certified and installed with 'approved' components. The exception to that is rental properties (which I own). No solid fuel appliance allowed in rental properties, only NG or propane furnaces.

 

[mrmikey]

Tell them you are doing your own uncertified repairs on heating appliances and watch your coverage disappear...and good luck getting off the black list

Yup you're right. Although saying that, when I bought the place I'm in it had a woodstove already but it wasn't a WETT certified/inspected install. I just had to get it inspected and all was good.
I was going to put one in my garage,...that was a different matter. Had to have bollards around it, so far from the wall (understandable), not near a door, no gasoline storage on site and I think it may have had to have a concrete curb around it. Needless to say, no wood stove as it would have made the garage a big open space with no ability to put anything in it.

 

[aczlan]

Pressure tested it today, found 4 leaks in the back wall.
Top right is the one that was leaking when I saw it, the others are pinholes:

I am going to bet that the gasification part did NOT work properly after they replaced the firebricks, the nozzle brick was installed backwards so they had no flow through the nozzles.
This end was towards the door:

Instead of this one (they're supposed to be one unit, but it broke in the middle and now there's two halves):

The backside of one of the nozzle bricks:

The outer bricks look ok:

Some closer pictures of the back wall after taking a wire wheel to the leak points:

Aaron Z

 

[aczlan]

Tarm gave three different cleaning brushes for those tubes and to clean the firebox.
Since this is so bad a shape, I imagine the original owners lost them or threw them out.

I don't think I replied to this, but it came with a straight "poker" a rectangle brush and a tool to clean out below the firebox (like a straight poker, but with a piece of flat steel welded on the end).
That matches what the manual says was shipped with it.

Aaron Z

 

[dstig1]

With that many leaks (...so far...) aren't you more concerned that you should replace the whole back plate? I would expect that this is a sign that it is getting thin and is just going to keep springing new leaks as time and use go on.

Now getting back in there to weld a new plate is another whole story!

 

[dougtrr2]

I had an HS Tarm with natural gas backup. I bought it in 1993 and replaced it with a Woodgun in 2016. I also started springing leaks on the reinforcing stays. If you look, you can tell that they were robotically welded. I had several that started weeping, all in the same place. They leak where the weld starts and finishes. I hired a welder to attempt to fix them. He also worked on commercial boilers so he wasn't a stranger to boilers. He had a very difficult time and as I remember he had better luck with stick welding rather that wire feed. He would make the welds and then it would leak around the new weld. He chased it for quite a while.

One word of caution. As you know it is very difficult to access the place you need to weld. You have to squeeze upper body in through the door to have a good view of what you are doing. He had issues with his self darkening helmet going back to clear because the sensor would get blocked.

I would have replaced with an HS Tarm, but at the time they were not offering a dual fuel option anymore. The WoodGun is a better fit for me as it has a forced draft, and I need that it my situation.

I am heating over 2500 square feet with radiant floor and love it. I plumbed in and additional water storage tank. As I recall it is 119 gallons. If I recall correctly, if you go over 120 gallons then they have to meet pressure standards and the price goes up astromomically. As you know radiant flooring systems are not running much pressure.

Good luck,

Doug in SW IA

 

[aczlan]

Curiosity got the better of me, so I went out and drilled out the worst of the leak points with a 3/16" drill bit.

It looks like I was incorrect in my assumption, I was thinking that these were dimples stamped into flat plate, in actuality it was a flat plate that had slots cut into it and these are reinforcing slats or stays that are welded from one wall to the other to keep the walls from spreading apart. Thanks @dougtrr2 for pointing that out.

If my HF micrometer is accurate, the metal has not eroded, it is still 1/4" thick.

The leak is a crack at the point where the stay is welded into the wall plate.

A couple of pictures:

Also found a couple more leaking stays on the sides, one on each side.
Right side:

Left side:

So I guess the question is, do I weld these up with the stick (and if so which rod), or with a MIG...
From what @dougtrr2 said of his it sounds like stick may be better and I may be chasing my tail with leaks on this.
I am thinking that if I can get it to weld up that I may want to hit all the stays in the firebox as a precautionary measure...

Aaron Z

 

[mrmikey]

Me, I'd go with stick, stainless steel, 308 or 312 type. Get it clean with a grinder, all the flakes and rust off, V it out a bit. Don't end the weld right at the point where you think the crack ends, run it past onto good metal