OWB Project

[Stihl310]

Well after tons and tons of research I finally jumped in a began the build on my OWB. Originally I had planned on fabbing the thing up all myself, however a machine shop we use at work quoted it out to be cheaper for them to build it than it was for me to buy the material (for the firebox and outer jacket). Since they were slow and the fact that I'd rather have professionals welding it I figured I would let them go for it.

I picked it up yesterday afternoon and got it home last night (anyone wanna come help me figure out how to get it out of my truck?) It's sat in my garage ever since as I haven't had time to even touch it with all the snow we got.

I plan on picking my pump up tomorrow after work, my heat exchanger should be in tomorrow as well. I think with the way the weather is that I'll try to rent a metal break over the weekend and get the tin bent for my plenum on my furnace and try to get the last of the copper ran and the HX installed.

I plan on getting the burner installed as soon as the ground thaws out and dries out. I'm actually installing it right where my propane tank currently sets.

I'll be insulating it with regular R-30 fiberglass batts, so in total I'll have aorund 6" of insulation. For the outside I've already purchased some green metal ribbed barn siding. Originally I was going to frame up the outer walls with angle iron, however I got the idea the other night at Home Depot to use steel studs, this will cut down on weight and almost eliminate welding altogether making everything alot easier.

For my door I'll be cutting out a square 1/4" cover plate and bolting it to the face of the burning, cutting a 16" x 17" square hole for the wood. After this I plan on welding a square 1/4" steel protrusion offset 1" from the edge of the opening, this will extend out 1" and create my door seal. For my door I am going to weld up an insulated 5" thick door, faced front and back with 1/4" steel, with internal gussets to prevent warping.

This is a big project and feels much the same stress as building a house, however I went through that last spring, so this should be a drop in the bucket. I plan on taking pictures and doing small write ups along the way as I build it and I will post all of that on here for the benefit of others, maybe someone can learn from something I did, and if nothing else atleast learn what not to do.

Attached are some pics of the 1" Copper supply and return lines, I also stubbed down for my future hookup to my hot water heater. (don't plan on doing this right away) Anyways I'm at a stand still on the copper until I can get the heat exchanger in, I'm stubbed all the way to the wall where I plan to bring the Thermopex in.

Well here's the pics, first is the copper runs, second is pressure testing the lines for leaks (none so far!!!) Next couple of pics are of the burner in the truck, stil can't figure out how to get it out... that and the fact that its' frozen to the bed...

Enjoy...

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[Stihl310]

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[ericjeeper]

Hollow all the way through it? Or is there water at the end of the firebox?

 

[mantis]

Looks like a good start.keep us posted

 

[Stihl310]

Hollow all the way through it? Or is there water at the end of the firebox?

2" water jacket on the backside, I think in my original design ( i think you commented about the lack of water jacket on the back) I took your advice and added it to the backside to decrease heat loss and also decrease stress in the steel, since the old design would have had a round in the back that was super hot, then a ring around the outer that was kept cool by the water... I think that would have caused alot of stress in the steel, and could crack the welds... I think the design I have now will trap as much heat as possible and keep the stress on the steel down, since it will all move as one, rather than two different temp steels moving at different variables.

 

[WVwoodsman]

That looks great!! How much did it cost you for the materials and welding? What is the thickness of the steel for your water jacket/fire box?

Keep us posted!

 

[mbergeon]

Sounds like fun, but I would go with a bigger door.

 

[Jredsjeep]

i got my yukon furnace out of my truck by grabbing my come-along and parking under a swingset. picked it up then drove away, dropped it on a dolly and pulled it with my tractor to my basement.

looks nice!

 

[Stihl310]

That looks great!! How much did it cost you for the materials and welding? What is the thickness of the steel for your water jacket/fire box?

Keep us posted!

Water jacket is 3/16" and firebox is 1/4"

 

[Stihl310]

Sounds like fun, but I would go with a bigger door.

That's kind of what I'm debating, I don't want too big, but I don't want to have to split everything down... I was figuring this size would be sufficient, I'm going to lay the door design out in CAD this weekend, and get a cut list together so I can have the shop shear the pieces out.

Thanks

 

[Stihl310]

Well I finally got it out of my truck, my buddy came over and we slid it out the back... once it was on it's way out there was no stopping it... that thing has to weigh atleast 500lbs... it's a tank...

My heat exchanger delivery got delayed due to all the snow, if I don't get it in today, I'll probably start working on welding fittings on and getting the pump set up and in place. I'm hoping by next weekend I can have the final design done on my door so that I can start on welding it up.

If nothing else I'll go grab some angle iron and get the base frame for the outside cut and welded together, then I can begin work on the outer walls and getting the roof framed in.

All I need to purchase is my thermostat, blower, and solenoid control for the damper. OTher than that all the parts are sitting in my garage, just got to figure out how to put them all together...

 

[Stihl310]

Got a steal on some angle iron racks at work today... just got to tear them down to get the usable steel out of them. Should help in the construction, I was cutting and fitting pipes tonight for the supply lines on the burner... Got them all cut and fit, just need to cut the holes into the water jacket. I'll post pics of this tomorrow when I get more into it.

Also my heat exchanger showed up today, I purchased it from freeheat4u on ebay.... looks good with absolutley no fin damage whatsoever. If it's too cold tomorrow I may just work on getting that put into my furnace, I'll have to do a little sheet metal work since my plenum is only 16x18. I"m hoping to just release the screws and slide the unit in, then let the plenum stretch the 1/8" it needs to, to accomodate the HX. I'll then have to add a little on tthe one end the accomodate the 18" lenght of the HX which is actually 20" with the frame.

I'll post pics tommorrow of what I do, all this snow sure makes me wish I had it up and going. I also hope to get the base of my outer frame fabbed up tomorrow, this will be the base for ym steel studded walls...

 

[R W Ohio]

We all like to see progress pictures,looks very good so far.

 

[Stihl310]

Got the hot water outlet welded in place today, along with getting the pump in place and bolted in. I also welded a fitting onto the front and installed a thermostat just for another visual to double check the temps.

My dad and I also installed the heat exchanged into the plenum on my furnace today. In all it was much easier than I had expected, it took a little over an hour, but we got it in and all sealed up. I will try to take some pictures of it tomorrow.

Anyways here are some pics of today's progress, not much but I'm slowly moving along. Next weekend I'm hoping to get the well in place for the thermocouple on my digital control thermostat, that and a visual water level valve so I can just flip it and check water levels. Only things left to do are build the door, cut in for the blower, cut in for return water, and put a drain in. Alot of work, but I should be able to get it done in one weekend. I'll keep posting pics as I go along.

Thanks

 

[motoman3b]

Curious how much the material and labor was for shop to build you up the rough shell on this burner, Some of my relatives would like one and I told them it'd be easy to build but I dont have the time or equipment really to work with that thick of steel.

 

[Stihl310]

It was around $900, for me just to buy the material was slightly more than that... I figured it would be easier to have a professional shop do the main part of the welding and fabricating, then I can take it from there. I'm glad I did have them do it, the tank is welded on both sides where points of contact are made, and the welds look like that of a robot. Saved me alot of headaches and got the worst of it done for me.

 

[motoman3b]

Wow yeah that is a good price! I should check and see what shops around here would charge.

 

[atlarge54]

I believe a rule of thumb is not to pump down---air bubbles rise---pump up. Have you considered firebrick to shield your door? I've threatened to put firebrick on the inner side of my OWB to reflect some heat inward.

 

[Stihl310]

Guess I'm not sure how I could pump up... my lines will be coming up out of the ground so I have to pump down. Once the lines are purged there shouldn't be any problem with air bubbles.

 

[atlarge54]

Pumps can be placed almost any way you wish, some better than others. I was advised to pump into the boiler, because pump runs cooler. On open systems (nonpressurized) the "smart guys" say keep the pump as low as possible. The concern was low pressure at the impeller causing cavitation and lower boiling point which can destroy an impeller. If your lines come in the basement that would be a better pump location. It's your system so do as you please, just remember the laws of physics aren't very flexible.