DIY Hack: How I hooked up my water heater to my wood stove
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- Опубліковано 4 гру 2022
- Here are the things I have learned in the process of hooking setting up my wood stove to heat the water in my domestic hot water heater to get free hot water that is more reliable than a solar water heater in he winter!
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As a plumber I am impressed. By raising the water heater you helped eliminate a heat trap condition. Free hot water for the win !!.
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Heat rises, fits that logic. Could have also laid the copper line flat.
My water heater is in the basement but the stove is upstairs. Would a gooseneck work?
@@jasonbrown7258 I am not sure what a gooseneck is?
Raising the tank did nothing to help the thermosiphon. I have my water inlet lower than the heat exchanger on purpose, to stop reverse thermosiphoning. This could be why you're losing heat.
I love home brewed engineering projects like this. Very nice job. Adding onto the loop as much as possible would definitely increase the efficiency.
Truth!
Incredible video. We are working on our homestead here in Tennessee to build a more self reliant system. This is great information. Thank you for sharing. Also, lots of great advice in the comments. I'm sure this video will help lots of people. Thank you
Thanks for the feedback! My goal on our homestead is to be as self sufficient as we can! Please don't forget to hit that subscribe button!
@@portercreek Already done! I look forward to seeing more.
Appreciate this video. Often wondered if the wood stove / water heating combo was possible. Thanks for demonstrating it!
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New subscriber.
I dig how you explained all of your fittings. You're right, not a bunch out there on the Tube about the "nuts and bolts" of this conversion.
Car radiator installed on either side, instead of your zig-zag.
Thank you! I suppose the car radiator would work if I removed the shroud and left it off. There would be a little more ingenuity to get the plumbing to work.
I'm very close to purchasing a Tim Sistem North wood cook stove with built in exchanger. My plumber just worked out a system and it is exactly what you have done here. I'm glad to know we're on the right path!
Nice! I would love to have a cook stove!
Nice job, very good description of the parts too!
Thanks!
I am putting in a 30x40 shop. I plan to put in a wood stove immediately and will tube the concrete for radiant heat. This may be a good system to marry the two. Thanks for sharing.
If you do try to heat the pex tube through the concrete floor you will need to do a heat exchanger on each side and some on top of the stove to make enough of a difference because that is a lot of mass to heat.
My buddy’s dad built a shielded manifold that sits inside his XL wood stove, he designed his house to have the water heated on his roof. During the winter the water can be practically boiling.
During the summer he uses solar hydronic heating from a heat exchange system he built into his roof.
Winter power is assisted by his seasonal creek and a micro-hydro system and a brushless alternator. The (vertical) head is only 100 feet.
The ingenuity of the homesteaders in that area of NorCal to live more in harmony with nature is absolutely mind-blowing.
I wish I had a creek running through my property! I would love to build a hydro generator!
It is fun to see the ingenuity behind some old timers projects!
You are correct. I have a wood fired hot tub heater. It requires a significant angle of cold water from tub to heater for it to thermo siphon. Very clever. More surface area will help for sure. If you can increase angle from heater to stove that would also help.
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What about the heat exchangers they have on CPU’s would
I grew up through the 60s,70s,80s and 90s with a kitchen wood stove with a connected hot water heater. Dad removed the bathtub and put in a shower. We always had plenty of hot water.
Gotta love free hot water!!
Nice job thanks for the video. Any little bit of independence is a great feeling. I think these sorts of ideas will become more important for the times we're in. Again thanks good stuff
I agree! Thanks!
My Coonara from 1986 came factory with this exact system, linked to a copper vat in the roof... still working to this day without fault...
They just don’t make things like they used to!!!
This video was very helpful... thanks!
No problem! Thanks for watching!
We heated our house and heated our water with wood for over 30 years! I bet the power company wondered why our electric use actually dropped in winter! I used an 80 gallon electric water heater as the tank. I pulled out the heating elements and ran the heavier gauge 3/4” copper pipe into our Kalamazoo furnace from those openings. The manufacturer gave instructions with the furnace and it had knockouts for the pipe. I did as you did and raised the tank up 16” on two layers of concrete blocks. It worked like a charm! The tank had the temperature and pressure relief valve already. I had it set up feeding into the household electric water heater. I turned off the power to the normal water heater in winter and never ran out of hot water, and we had two daughters living at home! The pop off valve actuated often!
That’s great!
@@portercreek oh yeah, I wrapped the tank with r13 fiberglass insulation and insulated the exposed pipes. Point is, using a dedicated electric water heater as the tank made the setup pretty easy and it had a lot of features as is that are needed for this thermo-syphon system work! Thanks for the video!
Looks like a good system. Our woodstove has a plenum chamber above it that ties into the hot air return for our HVAC system. We have a water heater with a heat pump on top of it. When we have a fire in the woodstove, the utility room gets relatively warm ( >60 degrees) and the heat pump on the water heater extracts that warmth to give us hot water. After rebates, the water heater with heat pump was less than $600 and it is saving us probably $250/yr over what the previous electric-only tank was using. As a bonus, the cold output from the heat pump on the water heater is vented into our garage, giving us a small A/C unit. :)
Nice!
@jasonbroom7147 can you direct me to where I could find more information that setup. We just bought a house with a hvac tied woodstove. Very interested in what you've got going on
@@SirloinBeefBurger - I've honestly never seen anything like it, before or since. Imagine a large metal box above the fireplace insert, forward of the flue channel. On top of that box are two round stand-offs with insulated flexible heater hoses that tie into the hot air return for the furnace. I don't think it was a commercially-made product, just something the mason who installed the brick fireplace built.
My great-grandparents had a water heater connected to their oil coal and wood range in the 40s.
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We had a wood stove in the early seventies that also heated our water with pipes set in the back of the firebox and oven. We were on tank water and the tank was above the level of the stove but the hot water tank was on the bottom floor of the house where the showers were. We only had a sink that used hot water on the top floor. It was probably set up in the 50’s when the house was first renovated and worked pretty well and I think was standard for farm houses in the area at the time. I like cooking on wood stoves but looking after them and the wood was a pain-in the butt.
Thanks for sharing!
Why not wrap the water pipe tight around the smoke pipe? Extract exhaust gas heat.
I get mine from next door, tapped into their plumbing whilst they were on holiday.
Haha!
Haha
I used to work as an apprentice with a heating system installer a very long time ago. This was right at the time when circulating pumps were fairly common, but some people still choose to have pumpless system installed. These whole house central heating systems worked because of convection current alone. We started out with a minimum of 2" pipe from the furnace, and gradually stepp it down at the radiators, but the main circuit had to remain a minimum of 1" to make sure there's enough flow. Anyway, the point is, when you design a convection cycle based system, the diameter of your piping matters a lot. Even in a small system like this. If bigger pipes are not an option, you need a pump to circulate the water.
Thanks for sharing, I do have a pump installed and did not find it to be helpful. I will eventually modify the shroud in the side and go with 3/4” pipe I stead
I like what you have done so far I'd be uncomfortable using solder joints for the heating part though I know the water should keep it cool enough but if something go's wrong with the water flow it could all go bad very quickly and I think it would work better if you used 1 inch pipe and added 1 inch fittings to the tank I lived in a house with coal stove with a back boiler for hot water and radiators all around the house it worked amazingly well at the time I thought it was out dated and took to much effort but I wish I had a setup like that now
I wanted to go with soft copper but I couldn’t get as tight of bends with the soft. I also wanted to do 3/4 pipe but I would have to remake the shroud on the outside if I did anything thicker than half inch.
Very ingenious. I've been pondering how to do an add-on. Hadn't considered that the 'slope' in all the runs affects the thermosiphon.
I didn’t consider it with the first version then after a bunch more research I saw that it could be my problem and it made all the difference.
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This is a great idea but you need more surface area for your heat exchanger on the wood stove to be more efficient on heat extraction from the stove, do a lot more Z's to capture more heat. Awesome project though!
I added 1 more zig zag to this current set up, it added a little more heat to the tank but there isn't room to add anymore to this side so I am planning on adding another one to the other side as well!
If you plan on adding zig zags I’d up the pipe size. Or use a circular spiral coil will give a lot less resistance over the pipe run. Looks good.
@@Elldeeve smaller pipe diameter gives you more surface area to heat the water, so it will give you less gpm of hot water but the water you put through it is much hotter. I am an engineer and homebrew beer so I understand how exchanging of heat works most efficiently, but in my job and hobby its usually cooling water but the same concept applies.
Great work!
Thanks!
I've been thinking about this idea for many years. I have to wait until I move to do it. Like what you've done. You can increase the pipe size to three-quarter, and that would help along with more zigzag and as somebody else said more thermal mass around it. They used to do this back in the old days. I have a book where they have a cooking wood stove like this. I have solar hot water heater. It has 120 gallon tank that feeds my 40 gallon tank and before that I have the old 40 gallon tank as a tempering tank. You would be surprised how much the tempering tank works. I took it out one day while I was putting on the solar tank in. it was amazing how many times the hot water tank came on. I wouldn't have believed it if I didn't see it with my own eyes. That tempering tank makes a big difference. When I put it together, I got the temperature control valve also .never put it on. It's sitting on top of the hot water tank. You could tell my family something 1000 times. They don't pay attention. You'd be amazed how people pay attention when they're going to get burned by water. Funny how they can pay attention to that. Nobody's ever got burned. They pay attention. My solar, hot water, his got up to 195° When I bought my solar, hot water system, the guy told me it's all about storage. You don't have enough storage. There used to be a magazine called home power. in it a guy built a cement storage tank because it was so big and lined it with plastic. I believe. it was massive. I think he had hot water heat too. Nice job and good work.
Thanks, I do intend to increase to 3/4” for a little more hot water during the shoulder months.
I got a couple of tips from this video. I am looking to tap into my baseboard hot water system. My boiler is on the same floor but a good distance from the fireplace (with insert ). So I will tap into the baseboard water line, just not sure if I am going to drill through the stove or have water piping on the outside of the stove. Though I would have had it done for this year but will be ready with plans & supplies this spring. The price of oil is now a big motivator.
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Stay well, Joe Z
I have a different design that I can up with for the other side that I am going to do for a boiler set up to heat my garage. The heat exchanger on the stove will have more to it to capture a lot more of the heat and I will have a circ pump hooked to that system. I was hoping to start on that project by now but I don’t think I’ll get to it until after the holidays.
I thought about putting the loop inside the wood stove but I didn’t want to sacrifice that space in the stove and I have a hard time wanting to drill holes through the firebox of a new stove.
Cost of gas was a big motivator for me!
@@portercreek Did you start on this project yet? If all goes according to plan LOL I will be starting mine in June
@@JOEZEP54 yes, it has been installed since fall. I made a mod to it shown in another video but it has been working great!
@@portercreek I will take a look. What is the title of the video?
@@JOEZEP54 ua-cam.com/video/OpYGPeS_cV4/v-deo.html
A few code / safety items you might want to look into , is your water heater approved for zero clearance from combustible materials. Two install drops down to the floor from your relief valves , this will protect you from being scalded if one opens when you are near it, you have no over temperature protection, closed system with no thermal expansion available. If the codes in your area require any or all of those items and they are not present it would allow your insurance company a way to avoid paying any damage or injury claims from a failure.
Thanks for commenting!
I like what you are doing
Thanks!
I was planning on doing something like this. If you need more hot water do more pipe in the stove do more in a bit lup
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I used a coiled up roll of copper tubing with no solder for the exchanger
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If you had thermal mass around the copper tubes up against the hot steel it would increase the efficiency of the heat transfer thus increasing your flow rate. That stove is hotter near the top then it is near the bottom due to how the fire brick lines it. Aluminum poured in a soild block around the copper tube would be ideal, you could also use an aluminum heat transfer plate made for pex radiant floor heat, anything like that around the tube is going to be better than air.
Good tip!
I was thinking about using steel wool to surround the copper pipe and add to the surface area around both the stove and the pipe to increase heat transfer.
@@SeattlePioneer Steel wool is flamable so I'd advise against using it. Fire brick mortar or molded clay packed in then a piece of ceramic insulation cover would help.
@@Tonnsfabrication Sand is also a good thermal mass. You just have to seal it in the panel somehow.
do it on the top @@pre176
I added a comment to 'Tom Running's' comment about water inlet height, but I wanted to comment on your heat exchanger setup. You've done a good job on the heat exchanger, but you need to concentrate the heat to the pipes and also stop the air current around it cooling it down. I would add flat plate copper to the side that touches your firebox and then add rockwool to the whole heat exchanger so that you're not losing heat. Let me know if that makes sense.
Good work on the unit.
Also any rise in the pipe coming from the firebox is ok, just NO falls, even level will work, it's just not ideal.
I can take photos of my setup but it might be confusing to work out.
Freddy :)
Thanks for commenting!
Personally, I heat water during the winter in a pan on my wood stove. I save a couple of quarts of hot water in thermos bottles.
I live alone and find that frugality is the key to simple hot water heating as described above. I use a towel and less than two quarts of hot water for bathing a shaving ----FLOODS of hot water are NOT required!
Hand washing dishes takes two quarts or less of hot water.
I use cold water in the clothes washer and hang the clothes on a clothes line to dry.
During the summer, I use my simple solar water heater ---- two quart plastic jugs set in styrofoam blocks that have been cut out to fit the jugs. Glass shelves salvaged from old refrigerators cover the jugs. On a nice sunny day I get water temperatures from 140-160 degrees F.
In the shoulder season when I'm not heating with wood and not getting much hot water from solar, I just heat water in a pan on my gas range.
I wouldn’t mind simplicity like that but with 4 kids it just doesn’t work!
Well Done! I am not a pro at this, but I am a bit worry about the solder, tin melts easily (450F), even you are willing to use lead (621F), you still run the risk of leakage in case of flow interruption. Take care😊
Thanks for commenting!
I have a similar set up, but it's never worked. It's a backup to the glycol solar water heating set up anyways and so I've never had it repaired. There are a couple days a year where it's too cloudy to heat up the water, but it's not been enough to motivate me to fix the "recirculation pump" set up as they call it.
I am really curious to see what your solar water heater set up is like, I didn’t think it would work in the winter months. How cold does it get during the coldest days?
@@portercreek I may post a video on my @wildweeds channel at some point showing the glycol solar water heating system. This morning the temperature got down to 13F and the lowest I've seen it has been 8F last year. But that doesn't make any difference to the water heater... It's the amount of sun that makes the difference, but even on mostly cloudy days in December and January it works pretty well. Of course, there's no hot water until about noon around winter solstice.
Enjoyed your video, thought about this for a long time, my water heater is a bit removed from the stove, and I’d have to deal with a doorway. I wonder if a small circulation pump would work, less reliance on it thermally circulating?
Thanks! A circ pump and a thermostat should work!
Try using the internal part of a hydronic baseboard elements for the “zig-zag” , love the setup tho, 2 thumbs up from a 30 plumber
Thanks!!
If you're only getting a few degrees difference between the top and bottom hoses. It looks like not much of the heat is being transferred to the water, which would explain why it doesn't heat the water too well.
A larger calorifier coil in the tank may help you get more out of the system.
As a kid, our wood burner (A 7KW Hunter) Used to heat the water piping hot, and a lot quicker than the electric element.
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We’ve been using a wood burner with back boiler ( thermosyphon) for 20+ years for underfloor heating via heat exchanger and circulating pump, with an excess heat dump using 3way wax stat…….works brilliantly.
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Great job I've been thinking about doing this for a while and I have a question doesn't the heat of the stove melt the solder
While there is water in the pipes it cannot because water is cooling it.
Similar concept to putting a plastic solo cup filled with water on a log in a camp fire, the top of cup will melt where there is no water but the rest will not and the water will temp will raise to a boil.
This is a good effort. Just keep an eye on the heat exchanger as I am not sure how long thin copper will stand up to the chemicals in burning wood.
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Seems to me the copper is on the outside under the panel and never touches the flames.
@@RRaucina it doesn’t!
As Kurt Vonnagut said, "THANKS ALOT BIG BRAIN!"
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I would suggest putting the wood stove heat exchanger around the flue pipe, most wood stoves use a 6 inch flue pipe for exhausting the stove. Because the diameter of 6 in pipe
Is quite small to bend 1/2 copper pipe around the chimney the use 3/8 pipe. The heat transfer would be much higher using this type of heat exchanger. The size of heat exchanger pipe would not matter that much as the flow would is quite low.
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i considered doing a solar water heater panel to a tank and they said if you dont want to use a circulator you need to have tank above the solar panel to actually get it to flow on its own from cold water sinking and hot water rising into tank.
My grandmothers house had a crazy way to heat hot water they only had coal since they were in a coal town, so they put a cast iron knuckle inside the flue of coal stove in kitchen and just ran hot water line through it that was a crazy system the hot water came out ice cold them wham like 180-degree water came out it was great for getting burned if washing hands. i don't know what kept water from boiling in the knuckle it was about 4 feet above stove.
I have thought about it for summertime hot water!
I think You might have had air in the line. Also line size is on the small side. Thermosiphon will work if the cold is lower also. Interesting setup there. Make your lines bigger will help with make up water.
I was limited to the half inch because 3/4 wouldn’t have fit under the shroud.
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Nice i have a wood cook stove with this built in to it
Nice! Those cook stoves are pretty neat! Thanks for commenting, please hit that subscribe button if you haven’t already!
use malable copper tubing and coil it around the black flue pipe.... lots of heat transfer that way and much better flow due to the heat transfer. also no joints at the heat source
I didn’t do that for 3 reasons how .
1) Aesthetically I didn’t want to see that
2) it would cool the flue which would increase chances of condensation and build up as well as reduce draft.
3) the flue is hottest during the first hr or so and then the temp really starts to drop as the volatile gases burn off early in the burn and transitions to more coals. The firebox on the other hand gets hotter and stays hotter much longer giving me a more constant heat.
Very nice,however if you used 45s for your turns the water would flow easier. 90s actually Restrict flow.
But I like that you are showing this.
The reason I didn’t use 45s is because of the space it requires.
Thanks!
Looks good, when valved off how hot does the exchanger get? Always wondered if it would open the relief. Had similar thoughts on running radiant floor Off a wood stove. With a circ pump though.
I haven’t tried closing both valves with a fire, I am a little reluctant to, lol! I want to put another, bigger heat exchanger on the other side to run hot water out to my garage to heat that. I am hoping to get that done before the end of the year. That one will have a circ pump on it.
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@@portercreek Your coil would just start flashing to Steam and your relief will start blasting off Steam Into your house
Thanks for sharing. Have you kept the water tanked hooked up to it's original heat source (electric or gas?) so that you still have hot water in the non-woodstove months?
It is gas, yes it is still hooked up
Add a check valve in the cold water intake and that will help create a hot water siphon
It works great the way it is, a check valve would reduce the flow
Hi. I love the simplicity, and the emphasis on safety. I wonder if you have the possibility to lower your wood stove any, thus gaining a bigger height difference? Also, what are your thoughts about wrapping the copper around the chimney then into the tank? Simple open coils above the stove top and around the lower part of the chimney pipe? I am looking to do something like this for my trailer in the middle of nowhere. Thanks
i was thinking of the lower chimney thing as well one of the biggest problems i have experienced is the cooling of the fire interrupting the exhaust of the chimney. using metal piping inside the fireplace. but wondering if you only removed the heat from the chimney if the venting will still occur properly and keep the exhaust clean burning. if so having a water tank around the chimney essentially water cooling it might maximize the heat.
I didn’t wrap it around the chimney for 3 reasons,
1) I didn’t like the aesthetics of it.
2) it would reduce the chimney temp which would reduce the draft.
3) the firebox stays hotter longer than the chimney. Wrapping the chimney would produce hate water quickly but not for very long.
@portercreek Thanks, I appreciate your time to explain the difference to me.
Try plumbing in an old radiator instead of the copper pipes on the side of the woodstove. Just a thought. Nice work!
I thought about that but then I wouldn’t be able to put the shroud back on, which isn’t that big of a deal, but getting the plumbing to adapt from conventional plumbing to the radiator would be a bit of a challenge. Can an old car radiator handle 60psi from the water lines?
Andy Hentges good call! I'm not sure if a radiator would be able to handle that pressure? I'm just a normal "joe" with crazy ideas haha! I love your ingenuity! Keep it up.
@@ajwilson313 thanks! Please don’t forget to hit that subscribe button!
Andy, would adding a water heater blanket also help with holding the temp in the water heater?
I haven’t heard of that before, I will look into it! Thanks! Please don’t forget to hit that subscribe button if you haven’t already!
You could run soft copper tubing from your zig zag to the flue pipe and coil wrap the pipe as high as you can, then straight to the top of heater. Lots of heat to absorb off the single wall pipe.
I thought about running soft copper but getting a tight enough 90 was hard to do without a tube bender.
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@@portercreek I'm completely off grid and have a gravity fed system. Small rv tank above the stove. Cold comes down to bottom of flue pipe and coils around tight, then dumps back to tank. Shut offs on both in and out to isolate the coil when water is hot enough. Then we can use the sink or a small tub. Another gravity fed cold tank outside to mix at the faucet. Still tweaking things here and there.
@@sodman1987 Make sure you put a pressure safety relief valve on that coil if you were isolating it as well as an expansion tank
Two suggestions:
(1) Source a baseboard radiator tube with fins and use THAT for your internal pipes
(2) PLEASE build a safety fence around the wood stove, piping and water heater in addition to what I see that you have there already to protect that baby I see.
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For a heat exchanger could you use a stripped down 5 gal. Electric (or gas) water heater right on top of the stove?
I thought about it but the wood stove is now our living room space in the basement so we want it to look pretty 🤩
If we loose power youll have a hot bath in winter, well done,
That was my goal!
I need advice please. I would like to use my wood stove those way in the winter and have my supplemental water tank directly below my wood stove in the basement and have that water heater feed the main water heater which is an indirect water heater. So I would create a closed loop feed the coil inside the indirect water heater for our domestic hot water during the winter. Any ideas are welcome.
If the water heater is below the wood stove, thermosiphoning would not work. The water tank would need to be higher. You could add a pump to the loop with a thermostat but you run the risk of cooling the water in your water heater.
Impressive secondary burn on that wood stove. What make or model is that?
Vogelzang 3200
My dad built in an exterior coil on a Vermont casting stove when he built his home with a circulator pump to move the water. He added a temperature sensor and controller to activate the pump. Additionally he would run an air solar collector to a water heat exchanger. He ran way more coil loops than what you have and could easily make lots of hot water. Great way to go. Maybe I will post a video of his setup.
I bet!
Dude you’re amazing! Will you just build me a house?
They aren’t that hard to build, just UA-cam it, you can totally do it!
That is genius! I'm impressed. But I would think the flames would melt the solder connections on heat exchanger. Does you boiler still work off gas? Since you said you can only heat enough water for two showers, will the gas part still fire if you need more hot water than the wood stove provides?
The flames don’t actually touch the copper pipes as they are on the outside of the firebox. In order for the solder to melt the pipe would have to exceed 300+ degrees and it can’t do that as long as there is water in the lines. The water heater still functions the same. I usually keep it off and sometimes will kick it on if we had a high demand of water that day. I have some parts coming next week that I will add to this system which should help it produce more heat. If the new parts aren’t enough to get me to 160 then I will add another zig zag to the heat exchanger which should definitely get me enough hot water for our whole family.
Once I get the new mod(s) done I will post a video so stay tuned! Thanks for commenting, please hit that subscribe button!
Andy
@@portercreek Awesome detail about the tubes not being in the firebox. I don't know much about stoves so that was nice to know that you can totally avoid the soot buildup on the tubes and loss of efficiency.
Great setup. I have a question. Does it have to be pipes for the heat exchanger?! I was thinking of putting something like a plate heat exchanger but without the plate inside. Just one big flat tube with an inlet at the bottom and a outlet at the top that i can stick to the back of the atove to cover the entire surface and get the maximum amount of heat. Will it work?!
I am not sure, I have not tested that method.
That would work but try and find a ready made flat plate cast unit. You could weld up a water box and weld it to the side of the stove. "Water backs" were common back in the day.
How do you handle the possible thermal expansion of hot water?
I have a well so there is a pressure tank that will accommodate the expansion. There is also a relief valve on the loop and on the water tank.
Good job! Did you ever consider the fact that you now will have electrolysis buildup on the inside of that panel where you installed the self tapping screw that is sitting against the short piece of copper spacer? Might want to use a copper plated screw next time.
Not sure how that would cause electrolysis build up when the panel had 4 metal screws in it from factory.
Ideally, copper should never touch steel. I use cardboard or lead flashing pieces to insulate copper from steel. But electrolysis is a peculiar thing that often does not follow the rules, so it may be okay@@portercreek
What about a continuous circle starting at the center? Not sure how it could be done but it'd be sweet
The flow always needs to be in an upward direction or it won’t naturally flow and you’d need to rely on a pump of sorts.
I would throw a small circulator on with a strap on squastat. You will get much more heat transfer than gravity flow. That is you ever needed more heat. Looks like it's working fine as is.
I have thought about putting one on to get the temps a little higher to give me more of a reserve and I probably will when I add another coil to the other side for the air exchanger I want to put in the garage.
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Very cool solution. I can only add that if you want to play with gravity circulation then you need to use large pipe cross sections. The energy receiver should be above the stove. If you have the opportunity try to coat the pipes with chamotte or sand to increase the exchange at the stove. Air is moderately suitable for energy transfer.
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Yea I would increase the amount of pipe for the heat exchange. Double or triple the amount of pipe.
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If your coil ever runs dry while you've got a fire going, you risk losing your solder joints. I'd recommend a stainless steel welded coil inside your firebox at some point. I know you don't have a lot of room, but an 80-gallon tank would be better. Also, if you coil was under your log holder, the temps would be higher (1400º) than on the side. More turns in your coils would be better, too.
I leave the water on 24/7 365 days a year
I've really been wanting to do this with my wood stove insert but my issue is that its on the first floor and the water heater is in the basement. I debated getting another small hot water tank and putting it in a first floor closet but again all my pipes are in the basement.
You could do something like this with a circulation pump. You would have to rig it up so the pump is on a thermostat though so your not cooling your hot water when the fire dies down.
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How about adding a second row of Z behind the heatshield for more surface area? I have no knowledge about those things. Only a thought.
This row of z is behind the heat shield, I am going to eventually swap out the half inch pipe with 3/4 to get better flow and heat transfer. I have also considered adding it to the other side as well
Have you considered using a recirculating pump rather than thermo siphon to circulate the water?
Yes, the draw backs are it required electricity and if the fire goes out and the pump is running it will start cooling the water instead of heating.
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I wonder if adding a small water pump to circulate water from the stove to the water heater would make this system more efficient?
I tried it and it didn’t not help
What do you do in the summer months
Currently I am using gas in the summer. I’d like to figure out a solar option eventually though
Is the tank you are using a gas hot water? In other words, wondering if you just have it turned off when you're using the woodstove, and then turn it on when necessary? @@portercreek
@@shirleyjones63 yes, I usually just leave it on during the shoulder months and then turn it off during the dead of winter when the fire is always going. We have 6 people in our house so we use a lot of hot water.
I think you were just air locked to begin with . A larger drain at the top would solve that . Nice job.
I bled the breather on the valve as well has the both pressure relief valves on the first and second go around. It worked the first time but just not well at all.
We usually will do a drainback system similar to a solar water system. This is only possible though when the water heater is in the basement and the wood stove on the first floor. When the water heater reaches temp an aquastat will deenergize the pump and the coil will drain back to a small intermediate tank.
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I believe the water coming out of the water should have a 2ft drop. I would check the code .
I am sure there is nothing code about this around my parts. You need a permit to think about doing a project in my county, it’s ridiculous.
You know how to run a fire, I almost thought it was gas lit, with a fake log. Put a sand box around it all. Yes it will be a pita if you get a leak to clean it all out and put it back. However it is all 100% recyclable. The bigger the thermal mass the more heat with less wood. To save on sand I used all the free bricks concreet I could find.
I just popped by to see if anyone had new Ideas.
Thanks!
Do you think it's necessary for your tank to be in the living room? It might be a good idea to conceal it or place it somewhere safer for the kids, and it would also enhance the aesthetic of the room."
This is my basement so I am not too concerned with looks
Great video but your understanding of thermosiphon seems a bit jaded. My grandpa used solar panel water heating- with outgoing and incoming pipes going 20’ from the basement.
Raising the water header a few inches to create a pitch for the tank to “drain” into the heat exchanger will have no impact on performance.
What you could do is increase the area of copper pipe on your exchanger. -Use a direct to flame coil inside the burner.
Water going to the primary cold inlet on the water heater should pass through the coil. Depending on your system 3/4” or 1” pipe would be necessary.
When everything is shut off water moves slowly, circulating “looking for heat”.
Your setup should save you on water heating costs! Good job!
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So it is a year later, does the thing work well ? Have you improved on it since ?
It still works great! I will likely make it a little bigger some day…
@@portercreek myself also, its such a great value, I'd go a little bigger too. with the damper on it, it would just function more efficiently.
Glad to find this - we're planning on doing something similar for an offgrid house. Except we were thinking of coiling the copper around the stove's exhaust pipe instead of a heat exchanger on the side like you have. It just seems like we could get a lot more heat exchanged coiled on the pipe as a lot more surface area would be in contact. Was also thinking of just a hot water circulation pump to make it work (the kind that constantly circulates the hot water in your pipes so you never have cold water waiting for the hot to get to the tap). Never done anything like this before....do you see any issues with the proposal? This whole thing makes me nervous, but we need hot water lol.
The only concern would be cooling your exhaust pipe too much would cause creosol to build up quicker.
I wouldn’t add the pump, it is just one more thing to rely on. As long as the pipe is always moving in an upward direction, you should be good.
Coiling a pipe around the stove pipe gets super hot and you don't really want to be adding /making steam under pressure without a way to supervise it, I wouldn't rely on a safety valve alone, a water heater that size (in the video) could flatten a 3000 sq. ft house if the pressure was to get high enough. As a Journeyman plumber/steamfitter for 30 plus years I would advise you to use caution and consider having a pro help you out on this.
How do you prevent it from over temp?
The higher the temp rises the longer it takes so go up a degree. I have never seen it over 145 though I would like to see it to run at about 160-170 continuously.
I think the only way it could ever over heat with my set up is if I had a roaring fire 24/7 and didn’t use any hot water for 30+ hrs.
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I did this for my hot tub. The copper leached into my tub. Use stainless steel.
Yes, do not use copper in a chlorine water application or it will leach into the hot tube water and will turn your hair green!
How much runtime on showers. 1-2 10 minute showers plus dishes? 1 30 minute shower no dishes?? Great DIY set up.
Yes about 10mins and some in my house take extremely hot showers(idk how they can take such a hot shower) and no one in this house knows how to shower quickly…. If it was just me in the house it would be more than enough hot water. As it is getting colder out it seems like the wood stove is keeping up with our hot water demands a little better as I keep the wood stove up more through out the day. I am going to do some mods to it next week to increase the hot water reserve. I will post a vid with the upgrades once I prove them to work. Hit that subscribe button so you can get notified when that vid is live. Thanks for watching!
using a flat coil of copper tubing as the heat exchanger instead of the elbows you might get better flow... i think you lose a bit of flow with each 90 degree elbow. and you might get more feet of piping with a coil also..
You would get more feet of piping with a coil but you would loose the thermal siphoning effect and would need to use a pump. What makes this set up work is that the flow of the pipe is in an upward motion all the way back to the water heater. If the pipe being heated goes down it would stop the flow of water.
@@portercreek oh ok i see what u mean... U shaped fittings might help with the flow.. just a thought.. really cool set up tho..
I just hooked up a coil of copper around my pipe, the water got so hot it almost exploded the cpvc pipe that was no where near the copper ends it connected to. I need to know what i should do to prevent this and the best way to control it.
I would run copper all the way to the tank because the water coming from the wood stove is going to be significantly hotter than the water in a water heater. The pvc piping is not rated to handle that kind of heat.
Are you an ammonia refrigeration guy by any chance? That's what I do and we use thermosyphon oil coolers on our ammonia compressors.
I am not…
@@portercreek Okay, just wondering because most people don't know what a thermosyphon is. Neat project.
Your application doesn't work for me but what a great idea if you are off grid awesome explanation bud
Thanks!
For safety you should have piping running to the ground for your PRV. I see your little guy over there & if that thing blew hot water would spray. Other than that awesome job!
It does, just didn’t have it done before I shot the video!
Thanks!
National Stoveworks (nationalstoveworks) has units with water jackets. Do any documents on their site show how many zig-zags or other design hints they have in their products?
Yea it looks like they run zig zags but all their stuff is inside the stove.
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@@portercreek I bought a house with one of their Model 500 stoves. I had to replace the oil burner, and I disconnected the water (it was a hacky mess from the prior owner anyway) and used the Model 500 as a regular wood stove until the old chimney gave up and I had to get a smaller wood stove. I thought it was really clever how you tucked those copper coils under the heat shield.
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Andy
What's the purpose of the green pipe coming down? Also, I see a thick white PVC pipe on top. What's its purpose?
The white pipe is exhaust for the water heater. It is a high efficiency water heater and the green hose is a condensation drain hose for the exhaust.
But heat exchanger into where fire is that would get it super hot but u gotta drip 2 holes in fore place haha
Yeah, I was trying to avoid that!
So what happens if no water is being used, but the woodstove is running? Doesnt the woodstove have the potential to overheat, and thus over pressurize the tank? i understand you have a pressure relief valve but, it doesnt seem theres any way to stop the stove from overheating the tank. I feel like blowing reliefs could be a common issue.
Also, keep in mind you could just use soft copper and a tubing bender to achieve the zig zags.
When no water is being used it, the hottest I have seen it get is about 142. The hotter the tank is, the more btus it requires to keep it hot because of heat loss through the sidewalls. With this set up I don’t think it is able to produce enough btus to over heat this large of an amount of water. I was going to us soft copper but couldn’t get the bends tight enough with out a tube bender and I didn’t want to spend the money on one.
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@@portercreek Good to know, ill consider doing the same to my basement wood stove then. thanks!
I think a circulator pump coming from the bottom of the water heater will improve your situation immensely😊🍻
I tried that m, it had actually worsened the situation
Wouldn’t the solder melt??
As long as there is water in it, no. Water can not exceed 212
Cool but 2 things way bigger diameter copper on the exchanger and way more using inside the stove or at least the flu and the top of the stove . 1'' pipe flows two thirds not half more CFM than a 1/2'' pipe. go big , thanks for sharing
My plan was to modify the shroud on the side of the stove to accommodate 3/4 inch pipe instead to get me a little more production! Thanks!
Be careful you don't heat the water to steam temps, as the pipes could explode. Perhaps you PRV would open and relieve the pressure, but sometimes they can corrode shut. Work the manual relief handle whenever you think of it to ensure it is free to open.
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