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Author Topic: How I improved my shaver boiler model 290  (Read 28222 times)

fletcher0780

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How I improved my shaver boiler model 290
« on: September 27, 2013, 09:37:17 AM »

I bought my outdoor wood boiler in 2008 and have had a series of issues I wanted to address to make the boiler more user-friendly and efficient. Below you will find a series of images and descriptions documenting this process.   



The boiler originally shipped with a rather rudimentary temperature control system consisting of a surface mount thermostat that cycled an electric blower on and off, and a manually adjusted draft door on the blower. I had a very difficult time regulating the temperature. I had frequent boil-overs and wide swings in water temp. I addressed the problem by adding a dry well, a solenoid,  and a two stage digital aquastat that is set as follows:
180* - blower off and damper closed
<180* but >=175* - blower off and damper open
<175* - blower on and damper open
The idea is to only use the blower when needed, as it forces hot air out the chimney and wastes heat.





The second issue I faced, was what I personally define as “poor insulation”. The boiler used some type of fiberglass batting on the to and sides, and nothing on the bottom of the water jacket. I decided to strip the tin, and ultimately the framing from the boiler and prep for spray foam. I was a bit disappointed to find the outer shell of the water jacket also had no paint and was beginning to rust:









I also discovered the water jacket was not welded solid around the top of the boiler, which essentially left me with a 50 gal air space above the water level:



I sandblasted the boiler, welded the gaps, and sealed the welds with polyurethane roofing sealer for good measure, then painted the boiler and tacked on studs to attach tin:













I also cut and threaded the overflow pipe on the side to direct it up through the roof and reclaim that unused 50 gallons of airspace for water storage.



Before I welded that ridiculous inspection cover in place, I added a couple 90* and a few pieces of pipe to the inside of the return pipe to direct the water to the front of the boiler and promote better circulation. Unfortunately I forgot to take pictures of this step.

Once this long and laborious process was complete, I was ready to have the boiler insulated with closed cell spray foam. I kept the foam away from the door and chimney area, I used rock wool high-temp insulation for those areas, along with in-between the inner and outer firebox door panel:











The single wall chimney was also a source of problems for me. At least twice during the winter it would clog up and I would have to climb onto the shed roof and attempt to clean it out. I decided to cut the existing chimney off about 12” above the tank, and bought some nice triple wall insulated pipe and a cap. I reused most of the existing tin, but had to buy a few corner pieces and covered the furnace





I added a switch to cut the power to the damper and blower while loading the stove:





Since I spray foamed the bottom of the boiler and the hot coals sit in the ash pan and could potentially melt the foam, I thought it best to line the ash pan with half-height firebricks. These bricks also raise the floor of the firebox even with the bottom of the cleanout door, which is a nice benefit.







I think I may also experiment with lining the floor and possibly the firebox walls with firebrick in an attempt to raise combustion temps and further improve efficiency. I’m going to experiment with a secondary burn air tube plumbed from the ash pan area, up along chimney, and along the ceiling of the firebox. I’ve drilled a series of holes in the pipe that runs along the firebox ceiling in hope that the air will help ignite the wood gasses and initiate a secondary burn. I’m not fully sold this will work, but it was an easy modification while I was working on the boiler:









From the factory, the door gaskets consist of a large bead of hi-temp silicone, which on my boiler, melted away every year. I decided to clean off the sealing area and glue a 1”x1/4” strip of nomex to both doors. If I can’t seal the firebox, all the sophisticated controls in the world won’t properly regulate the temperature.





I know I’ve missed a few items, and need more and better pictures of others, but this should be a good start. I’ll keep track of wood usage this winter to document any improvements. In the past winters, I’ve used about 12-14 full cord of hardwood to heat a three level (including finished basement) 3000ft house to 72*, an 800ft garage to 55*, and an 800ft apartment above the garage to 72*. Everything but the apartment has radiant floor heat, and both are well insulated. On the coldest spells, 3 days or more of constant below 20 weather, I had to load the boiler up to four times per day, and it would still never reach a 175* set point, the blower ran constantly.







In case you didn't notice in the pictures, there are actually two different 290's we did the same modifications on, so there is a mix of pictures.
« Last Edit: October 10, 2013, 08:53:24 AM by fletcher0780 »
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yoderheating

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Re: How I improved my shaver boiler model 290
« Reply #1 on: September 27, 2013, 09:45:19 AM »

 Wow that should help a lot. Its to bad you had to do all that work but you should have a much better product now.
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Scott7m

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Re: How I improved my shaver boiler model 290
« Reply #2 on: September 27, 2013, 08:49:27 PM »

Wow,you basically built a new furnace! Nice lookin home
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doow14

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Re: How I improved my shaver boiler model 290
« Reply #3 on: September 28, 2013, 02:50:38 AM »

Nice job you did a lot of things that should have been done when it was built.hope you see a big improvement.Looks like your tank drain is same as mine about 3/4 up from bottom of tank don't think you can, with any amount of flushing get every thing off the bottom that may settle down the road.just a thought.Good luck,stay posted.
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gandgracing

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Re: How I improved my shaver boiler model 290
« Reply #4 on: September 28, 2013, 07:24:20 AM »

One other thing I could add that has made it easier for me is to raise the stove about a foot.  A lot easier to load and see into the back of it.
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rugerman

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Re: How I improved my shaver boiler model 290
« Reply #5 on: September 30, 2013, 09:44:36 AM »

with top welded shut how do you add boiler treatment
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fletcher0780

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Re: How I improved my shaver boiler model 290
« Reply #6 on: September 30, 2013, 12:06:57 PM »

with top welded shut how do you add boiler treatment

Just pour it in the overflow with a funnel like every other outdoor boiler.
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coolidge

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Re: How I improved my shaver boiler model 290
« Reply #7 on: September 30, 2013, 05:57:41 PM »

Nice job on the rebuild, I would like to say be carefull with the closed cell foam, the auto ignition temp is right around 400 degrees. An overheat and the whole works could go up in flames.
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fletcher0780

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Re: How I improved my shaver boiler model 290
« Reply #8 on: October 10, 2013, 08:53:37 AM »

One issue I noticed after the fact, which is a pretty big fail, is the overflow port was re-engineered incorrectly. It is in the original position and just extended up with a 90*, but what happens when you try to fill above that port is the air gap above the water level begins to compress and has nowhere to go, so it pushes water out the overflow without fully filling the boiler. I'm going to drill and tap a 1/8" NPT hole into that double plate piece behind the chimney to allow the air to escape and the boiler to fill completely. I should have caught this to begin with, but there were so many issues to address I missed this one. Hopefully anyone following in my footsteps can address this correctly from the beginning by eliminating the side overflow pipe and move it to the top of the water jacket. I'll post pictures of this correction shortly.
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gandgracing

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Re: How I improved my shaver boiler model 290
« Reply #9 on: October 10, 2013, 03:14:58 PM »

I know just what you mean about the vent.  When I had my bottom and top of the water jacket replaced we did away with the access panel in the top rear and brought the vent out the top with a 1" piece of pipe.  It was still burping until I figured out the stove  wasn't level and it was leaving an air pocket in the back.  Fixed that and all good now.
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fletcher0780

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Re: How I improved my shaver boiler model 290
« Reply #10 on: October 15, 2013, 11:46:05 AM »

So, I drilled a hole through the tin and insulation with a 1" hole saw and then drilled a 7/16 hole through the top of the water jacket (where there's an extra support plate on top of the boiler). Once I drilled through both layers, I threaded the hole with a 1/4" NPT tap and threaded in my 8" nipple. I essentially have two overflow pipes now, but at least I can fill the boiler completely and don't have to deal with those pesky air bubbles. I plan to silicone around the pipe and re-insulate with spray foam, but I wanted to check for leaks first. I really wish I just added a 1.5 or 2" overflow to the top of the boiler when I had it all apart and eliminated the dumb pipe on the side, but live and learn.



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jimr

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Re: How I improved my shaver boiler model 290
« Reply #11 on: October 28, 2013, 08:15:20 AM »

just curious, how is the door gasket holding up
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fletcher0780

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Re: How I improved my shaver boiler model 290
« Reply #12 on: October 28, 2013, 06:34:46 PM »

just curious, how is the door gasket holding up

It's working great so far. I had to step it as I got away from the hinge, 1 layer on hinge side, then two, then three by latch. The two stage controller is also working well, but I had to turn my outdoor loop circulator on full time to keep an even temp throughout the inside of the boiler.
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jimr

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Re: How I improved my shaver boiler model 290
« Reply #13 on: October 29, 2013, 05:04:44 AM »

Was wondering about the door gasket. I installed a rope gasket in place of the silicon. After about 3 weeks of running the door gasket is pretty hard and starting to leak a little smoke, although it is not affecting the fire at idle, at least not now.  Is this normal for a rope gasket on the outside wood burner
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slimjim

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Re: How I improved my shaver boiler model 290
« Reply #14 on: October 31, 2013, 10:19:25 AM »

Yes, what size gasket is it?
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