ideas for custom outdoor masonry water stove

[Ericcc]

About 11 years ago I got a used Taylor water stove. It has served me very well, but it started leaking about a year ago, I added some "liquid stop leak" and bought some more time, but I think I'm going to have to drain it before the end of this winter, maybe even this week. If I can find someone to repair it after I drain it, I'll try to do that and use it however much longer I can, but I've been asking around, and it's looking my stove may just be at the end of its useful life. So what I want to ask about here are my ideas for a replacement.

I've thought about just buying a new water stove like the one I have now, but one major issue with that for me is that I'd really rather not use the anti-corrosion chemicals -- I'd be willing to make significant sacrifices, including extra cost, to avoid them, basically for organic kind of reasons, even though I've added some chemicals to my current stove (although not as much/often as recommended) -- and it seems foolish to buy a brand new stove and then not use the chemicals. (Sacrificial anode rods aren't at all a reasonable substitute for the liquid chemicals, are they?)

My leading idea right now is to build (have build) an outdoor masonry stove , I guess with firebrick and red brick, but build one with a large firebox like I have now, design it with a very simple flue system (not like for quick, high intensity burns but more like a common water stove, just out of masonry instead of steel), and then install a very small boiler over the firebox in my masonry -- I'm imagining something just the depth and width of my firebox and probably less than a foot tall -- and use the steam/hot water from that boiler to heat a large (multiple hundred gallon) water tank that wouldn't be exposed to direct heat from the fire, and then insulate all of the masonry and the tank together, so that whatever heat the masonry absorbed would gradually get transferred to the water tank as much as possible. I'm hoping I can get a tank, thinking stainless steel like maybe an old dairy tank, that I'm hoping would last for several decades even without any chemicals if used in this way. I figure the boiler is the only part likely to rust out anytime soon, but I'm hoping I can replace it for a lot less money than a new water stove if it ever does rust out.

Is anything like this feasible and reasonable? I figure I'll sacrifice some efficiency compared to my current stove (poorer heat transfer and therefore more heat going up the chimney), but I'm hoping not too much, and it could be worth it to me if I could have a stove that would function basically like the stove I have now but with parts that would mostly stand a good chance of lasting for a very long time without chemicals and could be replaced piecemeal as necessary.

Any other ideas for outdoor wood-fired hydronic heating besides the common water stoves?

The only other idea I have is to buy the smallest water stove I can find and then add a separate water tank to hold extra thermal mass.

 

[E Yoder]

I would think the storage tank will need to be treated unless it is pressurized. Any open system would usually use treatment to prevent electrolysis and sludge.
Designing a system like you describe will involve a fair amount of trial and error I'd guess. At least to get it to work well.
With the units I sell we treat once, then test yearly even though they're stainless. Usually once they're treated properly there's very little treatment being added yearly. I don't see it as a big environmental concern.
As far as alternatives to the common water stove, check out the new gasification boilers/outdoor furnaces out there. Giant leaps in efficiency and convenience.

 

[hedge wood]

If you don't like using chemicals I would buy or build you a system that is set up with pressure. Any open system is going to have problems without chemicals. Looking back on it I wish I had went closed instead of with my Garn.

 

[Ericcc]

I had no idea that pressurized systems would be any different in terms of need for chemicals, and I still have no understanding of why that would be the case. Your two comments definitely have me wanting to learn more about these things, though. If we're talking about pressurized systems does that necessarily mean steam instead of hot water? Currently I have pex lines running from my water stove to a heat exchanger in a blower unit that delivers heat to my house through the duct work. I definitely don't love the forced hot air system, particularly given some of the details of my own system, but if I continue to heat with hot water I was figuring I'd just keep using it because it's already there and fully functional. Is there any way that part of my heating system would be compatible with a pressurized system?

I could ask lots more follow-up questions, because you've given me lots of helpful ideas to consider, but I'll leave it at that, at least for now. Thanks!

 

[brenndatomu]

Pressurized hot water...but it will still need water treatment.
Whats the issue with treating the water anyways?

 

[maple1]

A closed pressurized system usually doesn't need treatment because it is isolated from the atmosphere. And the oxygen in it.

 

[maple1]

Pressurized hot water...but it will still need water treatment.
Whats the issue with treating the water anyways?

Its a bit of a pain. Usually consisting of annual testing and treatment.

 

[brenndatomu]

A closed pressurized system usually doesn't need treatment because it is isolated from the atmosphere. And the oxygen in it.

Its a bit of a pain. Usually consisting of annual testing and treatment.

Hmm...I respectfully disagree. I run/maintain the 650k BTU gas fired hot water boiler (low pressure) at work, and everything that I have ever been taught about this machine (which is 50 years old and gets a state boiler inspection every year, internally every 3) says that while we could run without treatment, we would have 10 times the maintenance/repairs, and lost efficiency (due to things being scaled/crapped up) Everyone that I have ever talked with about how it is being run/maintained highly agreed with our procedure, including my helper, who carries several different high pressure steam boiler licenses (formerly municipal power generation operating engineer)
It was re-tubed once and the company said after seeing the tubes, it was a waste of time and money.
The treatment is not expensive, and I only test once per year...doesn't take long at all, and is easy/cheap enough...not sure why the reluctance to treat...from everything I know about it, it is win/win to treat.
And as far as a leak goes, that would/should be infrequent, and in low volume, not a big environmental hazard. If draining the system, the water can go down the drain, especially if you are on city sewer service...not sure I would want to dump a large quantity down the drain to my septic system...I would have to research that a bit...certainly wouldn't want to dump it out on the ground in quantity...

 

[maple1]

It just doesn't seem to be done with indoor pressurized boilers/systems (at all around here), and from what I have seen it doesn't seem to be hurting anything. Have never heard of issues and there are lots of older setups. Parents place & system is 5 years younger than me, which would be 52 years & still going. Never an issue. Mine was in service for 17 years before I swapped. I checked inside it when I moved it out. All solid & black with that protective coating that a sealed system develops over use (think there is a techno name for that but it escapes me now). I did ask at the supply place about treatment stuff when putting my new one in, they looked at me like I had 2 heads. So I could likely have gotten something, from somewhere, and likely could get testing done, somewhere (not sure where but nowhere around here that I know of) - but ya, then it's a bit of a pain, from my point of view. If one was filling the system with water that could be acidic or something like that, then it should be a consideration - if in doubt, the fill water should be tested first for at least that. But I don't think even the OWB people around here do anything about it either (certainly not saying that is right).

 

[Ericcc]

So what kind of untreated systems are you talking about, @maple1 ? Are these all steam-generating systems? Or are there also minimally pressurized hot water systems that could be made compatible with the pex lines I currently have running to the heat exchanger in my blower unit?

And @hedge wood , what kinds of closed systems are you saying that you think now would have been better for you?

 

[Woodman1]

If the OP is going to consider a pressurized system make sure his existing pex lines are O2 barrier. Including the lines that are buried. My pressurized system has no chemicals. I thought that was one of the benefits of a pressurized system. I would not enjoy cracking it open every year to test,and then have to add fresh makeup water.

 

[Ericcc]

make sure his existing pex lines are O2 barrier

How do I figure that out? Will there be something written on the lines that I can look for?

 

[3fordasho]

No direct experience but I recall from obtaining by special class boiler license (basically the entry level license) that boiler treatments are common with pressurized industrial sized boiler systems along with annual water testing. We do have a couple gas fired boilers at work (one steam and one water) that require daily checks and log books and there is some water treatment done but rather inconsistent (I am not the operator for those) and they seem to live a normal life expectancy.

For my personal system (Attack 45kw with 1000 gallons closed storage) I run about .6 bar cold system pressure that will top out about 1.1 bar at full temperature. When filling that system I added 5 gallons of boiler rite #39 water treatment which is a nitrate treatment. Cost was about $100 and I can check nitrate levels on an annual basis and add a bit if necessary but I expect very minimal ongoing expense on this closed system. My take was this was optional on a small closed/pressurized system that does not need lots of make up water and I could have gone with no treatment as others have suggested here.

 

[Woodman1]

How do I figure that out? Will there be something written on the lines that I can look for?

Try to find the manufacturer of the pipe and verify with them. I believe most of the common colored red and blue tubing is not.

 

[Ericcc]

Are there regular "store-bought" options I could consider for a wood fired (preferably with a large firebox like I have now with my Taylor) closed system, warm water heating unit. If so where would I find out about them? What are the possible name brands/sources that I might reasonably be able to buy in the US?

 

[maple1]

Are there regular "store-bought" options I could consider for a wood fired (preferably with a large firebox like I have now with my Taylor) closed system, warm water heating unit. If so where would I find out about them? What are the possible name brands/sources that I might reasonably be able to buy in the US?

Look at everyones signatures for starters - most people posting have their stuff listed there. Check out the banner ads and sticky threads. All kinds of info all over this place. I got mine from Smokeless Heat. They have a banner ad that you should see once in a while.

 

[maple1]

So what kind of untreated systems are you talking about, @maple1 ? Are these all steam-generating systems? Or are there also minimally pressurized hot water systems that could be made compatible with the pex lines I currently have running to the heat exchanger in my blower unit?

And @hedge wood , what kinds of closed systems are you saying that you think now would have been better for you?

I don't think anyone here is making steam. Just hot water, and in the 15-20 psi range usually.

 

[brenndatomu]

boiler rite #39 water treatment which is a nitrate treatment. Cost was about $100 and I can check nitrate levels on an annual basis

Exactly what we use...

Damon Industries :: Chemical Cleaner Cleaning Custodian Custodial Degreaser Degreasing Deodorant Disinfectant Disinfecting Floor Finish Housekeeping Jan-San Janitor Janitorial Sanitizer Sanitizing Sealer Treatment Wax

 

[Ericcc]

Are all the pressurized wood-burning systems on the market gasification systems? I'm not at all inclined to want to trade the flexibility of a large firebox that can burn wood of any size I can lift and that isn't always necessarily well seasoned for greater efficiency, especially if these gasification systems are more expensive and come with electronics that could create higher repair costs and difficulties 10 or 20 years after purchase. I already have wood that I'm just letting rot on the forest floor because I don't need it, so although there's definitely work in cutting and gathering it, winters in my part of North Carolina just aren't cold enough for me to want to sacrifice for the sake of efficiency and low emissions.

Not to get too far off topic, but I also regularly use my current wood stove for burning bone scrap I get from a small-scale meat processor near me, which probably provides about 1/5 of my heat and leaves me with "bone char" that's worth enough to me as phosphorus fertilizer that I'd continue burning the bones in an open barrel just for the fertilizer if I couldn't burn them in my stove for heat, and I assume I wouldn't be able to burn bones in a gasification stove like I do in my current stove.

 

[maple1]

I have no idea about your bone thing, that's a new one to me. But most all new boilers sold these days are gasifier, pressurized or not. Unless maybe you happen to find an older model someone is working around new rules somehow in selling. I had no sacrifices at all in going gasser, nothing but gains and wouldn't have anything else.

 

[Ericcc]

Is it true that wood for gassifier stoves needs to be well seasoned and split to a smaller size than is necessary for an older stove like my old Taylor? And are there additional electronic components? And they're more expensive, right? Those are the things I'm thinking of -- I don't know how true or valid they actually are -- when I talk about making sacrifices for improved efficiency.

 

[maple1]

Is it true that wood for gassifier stoves needs to be well seasoned and split to a smaller size than is necessary for an older stove like my old Taylor? And are there additional electronic components? And they're more expensive, right? Those are the things I'm thinking of -- I don't know how true or valid they actually are -- when I talk about making sacrifices for improved efficiency.

The wood needs to be dry, yes. But it should also be dry if using a non-gasser, really. Smaller size makes it easier to get dry, and maybe gives better coaling & less bridging. Mine has no electronics, but not sure you can buy a new one of those now with the more recent EPA regs & certifications & all that. Not sure on more expensive, depends what else you could buy that you can compare with. Storage ups the cost, the amount also depending what you can source - it's not always necessary, but is for some and always makes them function better.

Sounds like for your priorities you should just go shop around local for what you can find for outdoor boilers. Used ones are always a gamble but might be the only thing that fits your wants.

 

[E Yoder]

Keep in mind that any new wood boiler installed to a residence must meet EPA requirements. The older Taylor, Hardy, etc OWB's are not legal for residential install but are still for sale since they can be legally installed to commercial buildings.
From what I'm seeing out there your only legal option is a gasification boiler. Coal boilers are legal to install and might burn your bone scraps fine (that's a new one for me), but it's not an "approved" fuel I'd guess. Actually I didn't know something like that would burn. Quite interesting.

 

[Woodman1]

Burning bones? I think I would not like to be down wind of that. Lol!

 

[SpaceBus]

I'm pretty sure the bone scraps have already been distilled and all the liquids are long gone. Bone char is used to filter many things, including making sugar white.