Yes, ANOTHER OWB build thread... (Tank in tank style)

[breymeyerfam]

Door flange cut and tacked. And yes, there was a significant amount of warp in the face plate. Had to make up roughly 1/8" to make the face of the door flange flat.

 

[breymeyerfam]

Less critical welds, so I'm burning the door flange in with MIG.

 

[TonyK]

I always enjoy the build threads. Keep up the good work.

 

[LondonNeil]

welds look fabulous, especially for mig!

 

[stratton]

Love the pics and progress

 

[breymeyerfam]

Inner door (I will cut in the draft blower duct when I figure out which blower I'm going with)

 

[breymeyerfam]

Quick question, how many CFM is everyones draft fans? I'm thinking 100-150 cfm should be adequate, but I don't want to go too much...

 

[H-Ranch]

Quick question, how many CFM is everyones draft fans? I'm thinking 100-150 cfm should be adequate, but I don't want to go too much...

Mine is ~150 CFM. I would like to try smaller though as I believe it is plenty to stoke the fire, and may be too much once the fire is going. A quick check of some of the commercial OWB's should give you a good idea what common sizes are.

 

[breymeyerfam]

Ordered 1TDP7 Dayton blower. 146cfm stated. Figured I'd go big and can always add a fan control later if I needed to slow it down. Getting ready to order fiberglass rope for the door gasket. Looking at the 1" diameter. That looks pretty standard for boilers. Lastly I want some opinions on location for draw and return ports on the tank. I was planning on drawing from the top rear of the water jacket and returning towards the front almost directly under the firebox. The water jacket is almost twice as long as the fire box, will drawing so far away from the firebox hurt me? I've always heard that water layers and the hottest will be in the top 25%. Here is a quick drawing roughly indicating front and rear while showing firebox in relation to the water jacket.

 

[hseII]

Mostly stick welded because stick is easiest out in the field. Plenty of wire feed FCAW setups used too.

I'll be honest, for an experienced pipe welder it's pretty bad welding in those pics.

I'll be honest, You personally can't see S H I T from these pictures when fooling with 6010.

Post up your 6010 welds and prove me wrong.

 

[cantoo]

Not sure what size my blower is but I also felt it was putting too much air into the fire. I spent hours on fabrication of a restrictor plate over part of the blower hole to reduce the air. Mainly it's a piece of duct tape that covers about an inch of the hole. Works for me. What I would like is a blower fan that has the ability to come on at full speed and then about 5 minutes later (when fire is going good) it slows down to about half speed or even just shuts off but leaves the damper door open for natural draft to slow the burn down to make for longer cooler burns. I think I'm loosing a lot of heat out the chimney especially in the summer when I'm running the owb at lower temperatures.

 

[Skeans]

Not sure what size my blower is but I also felt it was putting too much air into the fire. I spent hours on fabrication of a restrictor plate over part of the blower hole to reduce the air. Mainly it's a piece of duct tape that covers about an inch of the hole. Works for me. What I would like is a blower fan that has the ability to come on at full speed and then about 5 minutes later (when fire is going good) it slows down to about half speed or even just shuts off but leaves the damper door open for natural draft to slow the burn down to make for longer cooler burns. I think I'm loosing a lot of heat out the chimney especially in the summer when I'm running the owb at lower temperatures.

Couldn't you use an air knife?

Sent from my SAMSUNG-SM-G890A using Tapatalk

 

[cantoo]

Is that like an air guitar?
What I have works, might use a little more wood but I like cutting wood so it's ok with me. I like to keep things simple, much easier to keep working and if it stops working I am capable of fixing it with things on hand. Computerized things are for nerds not hill billies like us.

 

[Skeans]

Is that like an air guitar?
What I have works, might use a little more wood but I like cutting wood so it's ok with me. I like to keep things simple, much easier to keep working and if it stops working I am capable of fixing it with things on hand. Computerized things are for nerds not hill billies like us.

No its a manual operated guillotine used on turbo charged diesels to shut them down if they run away, the same idea could be used for limiting air flow.

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[cantoo]

Skeans, just googled them and yes they look like they might work and aren't really that complicated.

 

[breymeyerfam]

A timed relay would work perfect for what you were talking.

 

[breymeyerfam]

Not sure what size my blower is but I also felt it was putting too much air into the fire. I spent hours on fabrication of a restrictor plate over part of the blower hole to reduce the air. Mainly it's a piece of duct tape that covers about an inch of the hole. Works for me. What I would like is a blower fan that has the ability to come on at full speed and then about 5 minutes later (when fire is going good) it slows down to about half speed or even just shuts off but leaves the damper door open for natural draft to slow the burn down to make for longer cooler burns. I think I'm loosing a lot of heat out the chimney especially in the summer when I'm running the owb at lower temperatures.

What you need is an "interval on" timed relay. There are many different time lengths available, but it looks like there is one made by dayton that is adjustable from 10 seconds to 10 minutes. Can be found on ebay for $20ish. Very simple to hook up. Power in, power out, and a neutral. When power is applied the timer starts. Power out of relay is shut off when timer runs out. Relay resets when power is removed from relay(when boiler reaches temp and normally shuts blower down).

This is a very good idea and I think Im actually going to try it and see how it works. Only time I see an issue, would be when you first build a fire and want a longer burn. I plan on putting a draft fan on/ off switch on the front, so you can switch it off when loading anyway, this would allow you to reset the relay if you needed to have the blower keep running by just flicking the switch off and back on...

Anyone have any comments on where my supply and returns should be on the tank from my previous post of the rough drawing?

I got the draft blower in the mail today and the door gasket should be here by the weekend, so hopefully I can get the door finished up and start on the hinges and lock mechanism.

 

[H-Ranch]

Anyone have any comments on where my supply and returns should be on the tank from my previous post of the rough drawing?

Mine is a similar tank in tank design. I pull water from the top near the rear of the firebox and return it at the bottom center. It seems to work well enough and I don't know if different locations would be any improvement. The only caution I would say is not to make the feed line to the house too high so as not to run the pump dry if the water is low - 25% from the top would seem sufficient. I chose not to draw from the bottom in case there was any sediment in the tank. Don't put your aquastat probe too near to the return. Use valves on every line so you can shut them off if needed for service. Oh - and put in multiple inlet/outlet ports in case you ever decide to heat another building/swimming pool/hot tub/etc.

 

[cantoo]

Don't let your wife touch the owb. This is what happens when it's 100 outside, very little heat draw, Ash charcoal in the owb and she decides it's a good time to throw 6 pcs of 4x8' cardboard in the owb. "I was just trying to burn it before the rain got it all wet". PS, we're in a Total Burn Ban here now. I had to open the door because smoke was pouring out the seal and out the chimney. Needed air to burn up the smoke, 2 minutes later the water is boiling.

 

[H-Ranch]

You may also want to buy steel pipe fittings instead of malleable iron fittings if you haven't already thought of that for ease of welding when installing the ports.