Homemade contraption.

[Wortown Mick]

Im looking to make a homemade contraption of a heating system.

I want to build a heat exchanger to heat water over the firebox. I'm thinking an older steel wood stove with an exchanger built off the flue on top of it.
Pump water to another exchanger to make it work on an existing forced hot air system.

My first hurdle is selecting a stove, something heavily built, old ugly and square. Fairly big.

My second is an idea for my exchanger, I was considering an old steam radiator encased in steel to direct the exhaust gasses through, should heat up water pretty hot.

The next hurdle is a water-air exchanger, and a blower fan behind it. A circulator pump on the water line to make it function.

Fairly simple idea, I'm curious if anyone's got good suggestions.

 

[mga]

heating water could be dangerous.

consider as many safety devices as you can think of.

what if you have a long term power failure?

 

[jburlingham]

Im looking to make a homemade contraption of a heating system.

I want to build a heat exchanger to heat water over the firebox. I'm thinking an older steel wood stove with an exchanger built off the flue on top of it.
Pump water to another exchanger to make it work on an existing forced hot air system.

My first hurdle is selecting a stove, something heavily built, old ugly and square. Fairly big.

My second is an idea for my exchanger, I was considering an old steam radiator encased in steel to direct the exhaust gasses through, should heat up water pretty hot.

The next hurdle is a water-air exchanger, and a blower fan behind it. A circulator pump on the water line to make it function.

Fairly simple idea, I'm curious if anyone's got good suggestions.

Depends on the volume your looking for and how much you want to put into it.

You could go cheap with an aluminum radiator, all the way up to having stainless tubing custom welded into an exchanger. I would opt for the later and the see if there is a way to put it into the firebox itself, however depends on the scope of your project.

 

[Wortown Mick]

I can weld so ill be doing the fabricating. The idea is to supplement oil heat and just get heat into the forced hot air system.

I was thinking pressure relief valves & such.

Its possible to set up a system to work on convection but id rather set pumps up. In even of power failure a generator would run them fine.

 

[jburlingham]

Mick, assuming your up for a project I would invest in stainless steel tubing and weld up a radiator of sorts, you could put it inside the fire box of the stove near the top and a thick walled tubing should take some abuse if needed, a couple of holes through the steel of the stove could allow the the "exchanger" tubes to exit the stove and be tied in, braze them to the stove to keep CO from escaping and your good to go, a simple pressure relief valve from an air compressor can keep the system from going critical, and many have adjustable pressure settings.

All in all your Idea is sound and not far off from mine, best of luck with it and please post pictures when it's in process.

 

[ericjeeper]

Pressure relief pressure relief.. Otherwise you are building what is commonly referred to as a BOMB. You will need an expansion tank in the mix too..

 

[turnkey4099]

Pressure relief pressure relief.. Otherwise you are building what is commonly referred to as a BOMB. You will need an expansion tank in the mix too..

Amen to that!! Neighbor across the street out here in the county installed an old cookstove in his basement. It had a 'water back' with pipe connections to connect to something. He, or someone, capped the pipes. When he fired the stove the first time he wound up with shrapnel throughout the basement. None penetrated the overhead. Must have been a bit of water still in there.

Harry K

 

[lobsta1]

Just sent you a PM about what I have.
Al

 

[Junkfxr]

A heat exchanger in the flue gases will get a lot of creosote build up on it. Several years ago, I was experimenting with close to the same idea. I coiled up 60 feet of 3/8" copper tubing in the top of a steel box woodstove with the ends coming out through the side and plumbed it into an old 50 gallon water heater, brazed all of the joints. It only took a couple of hours before the T&P valve on the water heater started cracking open. All of this was done outside the garage "just in case". Be careful!!

 

[Mike Van]

If something ever happened in your home with a homemade un-inspected boiler, your insurance company would bail on you so fast you'd be spinning. Making a stove is one thing, adding a boiler to it by a non professional is asking for trouble. I couldn't put my home/family at that kind of risk to save a few $$$.

 

[rick2752]

I have had pretty good success heating a large home with wood stove by adding a few cold air returns in the right places. My stove is in basement and I tapped into the cold air return and added another in the ceiling near the wood stove. I then run the furnace fan full time and it circulates the heat through the entire house. Works pretty well.

 

[RacerX]

If something ever happened in your home with a homemade un-inspected boiler, your insurance company would bail on you so fast you'd be spinning. Making a stove is one thing, adding a boiler to it by a non professional is asking for trouble. I couldn't put my home/family at that kind of risk to save a few $$$.

I completely agree with Mike. Even the title of this thread screams trouble.

 

[mtfallsmikey]

If something ever happened in your home with a homemade un-inspected boiler, your insurance company would bail on you so fast you'd be spinning. Making a stove is one thing, adding a boiler to it by a non professional is asking for trouble. I couldn't put my home/family at that kind of risk to save a few $$$.

Might be ok if you are an ASME certified welder, with an endorsment for pressure vessels.....

Please don't try this!!!

 

[demographic]

I used to inspect the welds ( Dye Penetrant, Mag Particle and Radiographic testing) on some pretty massive pressurised steam boilers and can say that you really don't want to be running a pressurised system in a home made boiler.

When the big boilers go up it takes the street out.

The back boilers in fires I have seen on a smaller scale are unpressurised systems and if it all goes a bit wrong it boils off to atmospheric pressure and hopefully doesn't involve the local undertaker.

 

[Wortown Mick]

I used to inspect the welds ( Dye Penetrant, Mag Particle and Radiographic testing) on some pretty massive pressurised steam boilers and can say that you really don't want to be running a pressurised system in a home made boiler.

When the big boilers go up it takes the street out.

The back boilers in fires I have seen on a smaller scale are unpressurised systems and if it all goes a bit wrong it boils off to atmospheric pressure and hopefully doesn't involve the local undertaker.

I don't even need pressure, ok maybe what 2-3psi to circulate the water.
I wont be having much parasitic loss of the heat as the water only needs to travel 10 feet or so from heater to exchanger.

I understand the concerns people are having. I'm trying to use a wood stove as my firebox to keep it safe. I can make the water heater portion easily cleanable as well as free flowing to keep the creosote down.

I think I can make this work, maybe

 

[Wortown Mick]

Might be ok if you are an ASME certified welder, with an endorsment for pressure vessels.....

Please don't try this!!!

I never went about it, but I can pass my 3/8 v groove structural test plates

I just need water & smoketight.

 

[ericjeeper]

I never went about it, but I can pass my 3/8 v groove structural test plates

I just need water & smoketight.

It is not a matter of quality of welder.. It is a matter of quality of plumber.. You will need an expansion tank. a pressure relief valve.. and it can all work like you are hoping.

 

[flotek]

its alot easier to heat the air than the water ,the water will basicly cool the firebox and the flue which will cause alot of creosote and make poor heat ,sounds like a bad idea to me.

 

[Jkebxjunke]

if it were a sealed system yeas a bomb in the making... if it were an open system ( like OWB's ) they are vented to the atmosphere... no boom....
you are talking its like 10' away... couldnt you just put a 8" pipe to your cold air return line? and 'suck ' the excess heat into the system? put your fan on continuous or if so inclined put a thermostat in the room with the stove... when it gets too warm it comes on and removes some of the heat and distributes it to other areas of the house...

 

[Wortown Mick]

if it were a sealed system yeas a bomb in the making... if it were an open system ( like OWB's ) they are vented to the atmosphere... no boom....
you are talking its like 10' away... couldnt you just put a 8" pipe to your cold air return line? and 'suck ' the excess heat into the system? put your fan on continuous or if so inclined put a thermostat in the room with the stove... when it gets too warm it comes on and removes some of the heat and distributes it to other areas of the house...

Too inefficient.

Ive had a wood stove, I know moving the air around can wok but not for my layout. I need heated air forced through the ducts, not lukewarm air but hot.