How to get free hot water from your woodstove 

lol I love it , a man has to have his priorities. How can anyone do with out the JAMS!!! Thats awesome. You have to pay 26 bucks tho just for membership fee's? Wow. I'm thinking there has to be a way to beat that cost too. Great stuff, love your idea very helpful. Mother Earth News has been a staple for me over the years as well. Nice Job Peter. Peace!!

To cut down or eliminate your electric bill, try solar panels or other alternate energy. Startup can be a little steep but in the long run you pay less utilities. I know this post/video is about 4 years old.

Pretty much in agreement with you regarding the effectiveness of solar, that is why I have recently started a new pv solar installation company, www.nh.solar The building in which this convection coil setup is installed however is surrounde by tall pines and oaks so solar wasn't an option.

Thanks for the suggestion!

Keith Hill Great ideas Keith. If there were need for more heat from my design, I think a stove top placement such as you have described installed in the return line to the Convection Coil would greatly increase the hot water output. The main reason I use a vertically placed coil however is to create a constant natural flow in the loop to prevent spot overheating and the possibility of a catastrophic failure. The installation of a circulator pump and aquastat are not absolutely necessary, but they do greatly increase the efficiency. More details about this can be found on my website; Convectioncoil.com Like yourself I do use an outside air intake and it does make a huge difference in the comfort of my building. My stove is in a downstairs garage area with a concrete floor. I installed a 4' floor drain with a trap in the corner behind the stove. The trap is normally kept flooded to keep rodents and insects from coming in through it, but in the dead of winter when the critters are not active I blow out the water and use it as my air intake Great thoughts Keith, detailed and concise. Thanks for contributing!

+Keith Hill More power to you, Keith.Great ideas but 60 degress below..... Oh, Hell NO! Not for my Sunshine State blood! Alabama is far enough North for the ole' boy!

+Keith Hill, I'm really interested in heating water with a radiator/wood stove for a hot tub. Do you have any suggestions? I have considered copper coils incorporated into a rocket stove but haven't seen any successful plans on that idea and want to keep it simple. Thanks, Jay in Montana

Hi Jay. I heated my hot tub in Alaska with my boiler. I used a small stainless heat exchanger under the hot tub for fast water heating. It worked far better than electric. If you use a wood stove you could mount a small car radiator on top of the stove and enclose it inside a steel cover for astetics and functionality. I would use an aquastat to prevent the hot tub from getting too hot. Any additional heat generated can be used to heat your heat water tank for Domestic use. I believe I paid about $400-$500 for the heat exchanger at the time, but you could probably get by without the heat exchanger. Hope this helps.

Wendy Devereux It is a good suggestion Wendy, but as of yet my own coil doesn't have end caps to hold the vermiculite in place, just an outer shell made up from a 3' section of 12" stove pipe. The shell is for appearance only. Between the shell and the coil I actually am just using a 2' foot wide wrap of unfaced R-11 fiberglass. This was wired tied to the coil with a few wraps of the coil showing both top and bottom. That way the fiberglass is well away from the hot stove pipe and touches only the outside of my convection coil itself. I've never seen the water in the coil exceed 180 degrees so I feel that this is safe enough for now. To retain as much heat as possible in my coil I do have a few inches of Roxul poked in around the top, and yes it does touch the stove pipe. The ignition temp of the Roxul mineral wool insulation exceeds 2000 degrees ...hopefully the flue will never get even halfway to that hot!

+Phillip Patterson Actually I now have the coil wrapped with Morgan Thermal Ceramic 1" Superwool blanket, and shell with light steel. Superwool is made to wrap the stainless flue inserts that are often installed in older chimneys. It works so well that even after hours of running my stove really hot, I can lay my hand comfortable on the shell

There shouldn't be any electrolysis problem between the copper coil and the steel stovepipe because the contact is dry. I do however have dielectric unions where the copper pipe connects to the steel inner coil of the Steibel storage tank. I also make a point of doing an annual inspection of the sacrificial anode in the Steibel, so far so good. Good observation

I'd like to know the answer to this one too Mike as kinking copper pipe gets very expensive! I think it will take a machine using roller mandrels in order to get a coil that both fits the flue pipe really snugly and is perfectly formed

I am now using Superwool+ 1 inch ceramic insulation to wrap the convection coils and shelling it with sheet metal (36" flashing) painted with stove black. It looks great and the surface stays cool enough to touch at any time.

Certainly can't disagree with your good recommendation! I got around this by installing a very tall air hammer before the boileer relief valve. I filled the loop from the boiler drain at the bottom until it flowed out the opened relief valve. The air hammer extends a good foot above this point. Still... an expansion tank designed for solar use would be the better choice and my recommendation

I'll be looking forward to seeing a video where someone proves that 3/4 pipe can be smoothly bent this way without kinking the pipe or getting a hernia from wrestling with 60' of pipe filled with sand or ice

I've never had any discharge from the boiler pv valve and the pressure in the closed loop rarely gets above 15 pounds max, so elevating the boiling point apparently isn't necessay. I stick with water in the loop because the internal coils in the Steibel tank are in direct contact with domestic water.

ChemicalRefugee Taco is a USA manufacturer of plumbing apparatus. In this case there is a stainless model 005 circulator pump in my domestic/ radiant exchanger loop, and the cast iron 005 pump in the convection coil/ storage tank loop. The copper section of my closed convection coil loop is isolated from the iron internal coil in the Steibel storage tank by dielectric unions. Hopefully this will prevent any premature tank failure as you have described. The storage tank does indeed provide a huge domestic tempering factor before the domestic hot water system, but the primary reason for using the extra (storage) tank is to be able to combine my convection coil with a thermal solar summer hot water system. It also provides an extra 80 gallons of hot water storage over and above the 50 gallons in my Marathon electric water heater. This time of year (October) the sun in NH is fairly weak while at the same time I only need to fire up my woodstove occasionally to remove the chill. Neither the sun or my woodstove is providing much heat to the storage tank, but still there is some. I'd much rather pay for the amount of electricity required to heat my water from 85 degree more or less water in my storage tank than the 55 degrees of ground water. Perhaps I am using the wrong term in "tempering valve"?? I'm not a cerified plumber. It is simply an adjustable temperature controlled sliding mixing valve that mixes hot water with a proper amount of cold water to achieve a consistent output temperature. I set mine initially by feeding directly off my storage tank when it was well over 150F, and running the domestic feed over a thermometer for about five minutes. It has been working flawlessly since. There is both an expansion tank and a boiler relief valve in my convection loop, and I regard both as mandatory for any kind of hot water system. I flush and test the pressure relief valve at the start of each season. The water in the coil will never achieves the steam state both due to these mechanical safety items and the inherent nature of convection to my elevated storage tank. Quite simply, the hotter the water gets in my coil, the faster it flows. I pressure tested my closed convection loop to over 100 pounds before firing it up initially, and have never seen it exceed 45 pounds in operation, even when I deliberately pushed it by running the woodstove full tilt boogie for nearly an hour. I did see the storage tank rise to a peak of nearly 170F during that extreme test ( the circulator was set to a 135 degree turn on point and on consistantly during that test).

Interesting Mario, and I wish I knew why yours has done this. Just an uneducated guess but do you suppose that your loop might need a di-electric coupler?? or maybe a larger circulator pump? Some of my loop is cpvc and that seems to insulate it. My copper is only very slightly tarnished

convectioncoil I'm not using a circulator pump. My system works with thermal siphoning only. I'm chalking the tarnishing of the copper coil off as weird side effect then. Let's see how long it takes before it's oxidized to a degree that let's it fail.

Simple Aaron.. flow. Even though I use a circulator for increased efficiency, my original intent was to have the loop work well without needing one ...and it does

+Anne Anderson (Foxiepaws) I found that ice and sand did not work well at all with 3/4 pipe, but am told it does with much smaller diameters. Problem is the decrease in flow is logarithmic with the decease in diameter. If your need for hot water is minimal and you have adequate well insulated elevated storage, a hand formed 3/8 coil will likely suffice Anne. I went the 3/4 route because I needed enough capacity to pre-heat both my domestic hot water and radiant floor needs. You are right, the "safety valve thingy" is of paramount importance!

Tony Stone It hasn't proven to be a problem at all Tony. Bear in mind two things, first the coil is external of the flue pipe, and second that it is fully insulated. These two factors combined only allow a limited amount of heat to be withdrawn, probably no more than would be lost if there was no Convection Coil and the flue pipe were in direct contact to the atmosphere. I clean my flue out thoroughly each Spring and also open it from the tee at the back of my stove and check it visually from the bottom midwinter. In the four years I've been using this setup I have never noticed any problem at all. I do make it a habit of letting my stove run wide open for about fifteen minutes until my stack temp exceeds 450F degrees. It gets the cool wood from my morning loading well ignited and helps to burn out any deposit from the damped down overnight burn. I also added a secondary air intake to my Fisher Mama Bear, and more recently an internal baffle. The preheated air intake definitely made a positive difference in creosote buildup (see my other video). I don't know what effect the baffle will have yet for I've just recently installed it but will likely post another video on this as soon as I have some history for the mod

+BisdremisKostas I'm sure that a stove top heater would be more efficient, but efficiency wasn't really what my prime motivation was. I wanted a design that would constantly and naturally flow anytime it was acquiring heat, thus the need for a vertical coil. The Convection Coil won't by itself reduce he draw of your flue pipe, but a build up of creosote certainly would! The Convection Coil needs to be insulated not just so it will gather more heat, but also to be sure that it doesn't cool the stack temperature too much. I've never had any issue with creosote build up at all, especially since I added the secondary air intake shown in my Fisher modification video

Yeah, There is much for me to learn about filming videos, LOL... The website will ned to wait until next fall now. I sell solar pv for a living and the Spring season is starting to kick into high gear already. Here 'tiz the second week of April, I've just come back from a day of FABULOUS skiing at Cannon Mountain, there is still two feet of frozen snow in my dooryard, and yet the sun is already making it's irresistible strength very well known. The top of Cannon was in the clouds and cold today with all the trees encased in fresh rime ice, while the base was at about freezing but the sun was melting off snow quite rapidly. I drive out of my north facing home on a road still covered in winter's ice, and slide down the south face of my road in mud rim deep Spring in northern New Hampshire, I do truly love it!

convectioncoil.com understood,good work ! I will watch this again when I come around to do one for my house

I had suspended working on the Convection coils while I started a new pv solar installation business (www.nh.solar), but think I may have the time again next fall to begin making coils again. My intent at that time is to make up a machine to form the 3/4 tube around seamless stovepipe using the flue pipe as an arbor, just as you have suggested.

I don't use the aluminum anymore since switching to the Morgan Superwool+ insulation blanket. When I removed the aluminum foil after a couple of years of use however it was exactly as it was when I first wrapped it. For galvanic corrosion to occur I believe there would have to be an electrolyte, and this was a totally dry contact.

Mark Lammey No clue as to the actual flow rate Mark, but one of the main reasons I chose to go with 3/4 as opposed the much easier to form 1/ or even 3/8 inch was the flow rate. For example, the flow rate of 3/4 is more than double that of 1/2 inch pipe. When I first start my stove and the storage tank is still relatively cool,,the delta between the heated water leaving the coil and that of the water returning is about 20 degrees. At that point the only thing moving the flow is the convection, and the delta seems to indicate that there is an efficient exchange in the storage tank. I wanted the flow to be as free as possible to promote this, and thus the need for 3/4 pipe.

That would work and in hindsight I probably would have skipped the Steibel tank and just tee'd it directly into an 80 gallon Marathon tank. The domestic hot water outlet however would absolutely need a mixing valve.

It might work Janet, but bear in mind that this is an unwieldy 60 foot section, not a handy 2 or 3 foot piece ...still, it might work by attaching a long leading rope. Another factor is that I wish to be able to wrap the copper tube tightly enough around the flue pipe to slightly flatten and compress the inside to the flue (see Elderly Iron's good video on this), more heat will be transferred this way.

+Beth Oquist No, I do not plan to make coils for the storage tanks, there are plenty of specialized tanks like my Steibel currently available. Alternately you can simply T a Convection Coil directly into the inlet and outlet lines of an existing tank, but this does require a mixing valve to be installed in the domestic feed

PV person Yeah you're right, the video is poor quality. It was the first one I ever did and shot spur of the moment.

Yes the radiant floor is a closed loop system and fed by a heat exchanger. There is a radiant heat company in Maine with an excellent website that describes the merits of both open and closed systems, google Radiantec. I however am not a believer in mixing domestic and radiant water

Kanoee64 A good suggestion but I have come up with an easier solution, my coil is now wrapped fully with 1 inch Superwool+ ceramic blanket and finished off with a stove black sheet metal shell. It finally looks as good as it works! I really need to post a follow-up video to this one soon showing the finished Convection Coil. It will be detailed later this week on my website at; Convectioncoil.com

Hey John, To be honest I'm into this system for more like 3K if you include all of the solar components. Bear in mind though that there are HUGE incentives available right now for installing solar hot water. If I were doing this today and submitted my total for for these incentives, the Feds would give me a 30% tax credit, the State of NH a $1500 rebate, and my local utility another $600 rebate. Most of the cost is covered when you do a solar thermal install! Of course the Convection Coil, the piping, and the controls are all part of that same build, right?? The least expensive hookup would be to just elevate your existing hot water heater tank above the Convection Coil and park it somewhere near your woodstove. This is how it was done in the original Mother Earth News article titled Blazing Showers. I would guess that doing it that way would be a long weekend project and shouldn't cost more than a few hundred in plumbing and the materials to build a solid elevating rack. If you go this route, be certain to plumb a thermostatic mixing valve in your hot out to the domestic hot water! The CC will no doubt make the water in your heater much to hot to use without blending in some cold. Payback period? hard to say, but the general assumption is that your hot water is roughly 20% of a household's annual energy consumption.

convectioncoil.com The problem with the government incentive is: the materials have to be manufactured by a recognized company. The install also has to be done by a recognized contractor. At least that's the way it is here in IL.

+Goodtime Granny The cost of the plumbing was justified in about a year in what I saved in electricity to heat my hot water, and the woodstove was installed primarily as a heat source. I have an endless supply of firewood just from clearing my land, plus I really enjoy harvesting it. Bottom lie is that it probably did take me about three years to offset my investment and now I live freely and enjoy an endless supply of hot water. What did you pay for your hot water last year Granny??

Unfortunately no Robert. The coils I bought are as small as their machine could make them and actually measure about 6.3" id. It does make them simple to slip over the flue pipe, but I know that some efficiency is lost in the slight air gap. I am aiming to come up with a machine that will form the 3/4 pipe around the 22 gauge seamless flue pipe so tightly that it will slightly flatten the inner face of the copper pipe onto the flue pipe.

I think there would be a problem both with the buildup in the crevices, and how the copper coil might react to the exhaust gases and soot Travis. Keep us posted on this if you do it ;-)

PV person The sand method does work well with smaller tubing, but I thought it would prove far too heavy and unwieldy for forming 60 feet of copper pipe. I now form my Convection Coils using a machine I built the forms the coil around a mandrel with roller arbors. A three foot welded seam flue pipe is lipped over the mandrel to start off and the tubing coiled very tightly around it. Presently I'm only set up to market the completed coils within the North American market, thus the adherence to the admittedly obsolete imperial system

+Catherine Thomas Sorry about that Catherine, I've had to suspend my Convection Coil business for the last six month's. Right now though it looks as though I may be able to return to it soon, it works too good to ignore. I'll be sure to post the news in the tile line for this when I can give it a go again. It actually was a pretty good website!

Chad, is does this come in rolls of flexible woven batt, like fiberglass? The Roxul is fine for the heat rating, but crumbles when flexed.

Interesting Dexter, but I'm not sure your system would work this far north (42 degrees). There is very little power in the winter sun here, but plenty of trees for our wood supply. I do now have a 40 square foot solar thermal panel on my roof which easily supplies my all of summer hot water plus much of the spring and fall needs. It is plumbed to my Steibel storage tank as a second closed loop filled with polypro glycol. That is circulated with a 12 volt pump hooked directly to a dedicated small solar panel, it was cheap to do and it works great! You're right, simple is usually better.

i do agree you must decide what is best for were you live and i live in Texas and am having grate luck with my system also most hot water heater's are insulated good so even in a cold place it should work well i know the solar panels do perform better in cold weather so long as you have a good bit of sun to shine on them

Terry, my website is nearly done and I should be able to launch the rough draft of it later on this week (yeah ...finally!). Look for www.convectioncoil.com soon!

James Ashford Incorrect... That would only work if light was providing the heat energy. Painting the coils would cause in increase in heat transfer resistance.

+James Ashford, black only heats faster if the source of heat is light ... black does not reflect lite, so it has to absorb it ... that in turn excites the molecules in it, causing heat ... black has no affect on how fast or hot something will get from heat radiating from inside the pipe

3 usd per pound of copper, even if that coil weighed 30 pounds it would be still be less than 100$ on raw copper

last time i checked 3/4L copper was $4.30 or so a foot.

andrew Bob It works just fine Bob for my small living space. The Steibel SBB300 storage tank is the only heat source to my radiant floor's heat exchanger plate. For a larger living space you might find it necessary to add an auxiliary heat source in the storage tank to exchanger plate closed loop.

Kevin Olesik Good suggestion for the video on the inside of the flue pipe. I'll attempt to shoot one showing that when I clean my chimney later this spring. While I agree that a horizontally mounted coil would likely gather a greater amount of heat, there are multiple reasons I wouldn't suggest it. A hybrid system with a horizontal collector feeding into a vertical Convection Coil however does sound very intriguing. For more detail on this please refer to the suggestion by Keith Hill in a previous comment.

+Kevin Olesik No noticeable creosote buildup at all Kevin. Due to the Superwool insulation wrap around the outside of the coil and the fact that the cooler water returning from the tank is still usually at 100+ degrees, I think it might be removing even less heat than a bare flue pipe

convectioncoil well I am offering my services for free. Just because of the quality of your work and video. I can provide webhosting webdesign and domain name registration-on your business name this is about 12$ (contact me via pm for details) if you can write down on the paper a diagram for the tanks and scann it or take a shot send me and I will draw it in Visio

You are best served by using a two coil solar tank like my Steibel SBB300. The lower coil in my Steibel is the input coil specifically designed for solar. That closed loop is filled with glycol year round and has a very simple and effective combo controller/expansion tank/circulator module. The other auxiliary upper tank loop was originally intended to be connected to a more conventional boiler water heating system. The Steibel in turn now feeds into a propane tankless water heater ...just in case the tank isn't up to at least 120 degrees

You could do this more simply by just elevating your existing water tank if it is already near your woodstove and tee'ing into the cold feed and hot domestic outlet. The hot output from the convection coil would tie into the hot out from the water heater, and the return to the convection coil would come from the tee on the cold feed to the water tank. You might need to replace your existing expansion tank on the cold feed with a larger one, you might also want to have a gate valve on the line from the tank cold to the coil, and you would most definitely want to add a properly adjusted mixing valve on on the domestic hot output. By doing this, your existing heater would still be a suitable backup for those days when your auxiliary sources aren't working. You would also then be able to add a simple solar loop for use in the the summer months and drain it for the winter. Because you are now running consumable water through the system, you would need to bleach the completed system before using it, and you would also need to use a stainless circulator pump. Before going to "real" solar panels I just tied a 100' coil of black plastic pipe up on my roof as a collector. It looked Clampettish, but it worked great all summer long!

***** I didn't think it was a good idea to put my coil inside the flue for many reasons as discussed below in an older conversation. Mainly the reasoning revolved around the possible negative reaction of copper with the acids in the exhaust gases and the buildup of creosote around the cooler coil pipe. I think a vertically oriented stainless loop as described in the discussion below with J Mozinski might be a very good alternative to my coil setup. There were two main points I was trying to achieve when I came up with the idea of a vertically mounted insulated external coil rather than just an internal loop. I wanted to be absolutely sure of a strong natural convective flow while at the same time I didn't want to remove too much heat from the stack temperature. The Convection Coil design has met and exceeded both requirements well beyond my expectations. I agree that with the price of oil and oil related products right now, it isn't worth burning wood unless you have your own supply or can buy it right. The going price for split, seasoned wood in the Fall here in central NH is right around $250 a cord and a cord of hardwood is the equivalent of about 125 gallons of heating oil, so burning a cord saves maybe a couple of hundred dollars ...a questionable return for the labor and mess involved. But how long do you suppose oil will be this inexpensive?

convectioncoil.com Mostly that is overcome by using stainless steel pipe.

+Bob Roberts I've tried the collector inside the stove pipe. I had to rip it out from too much creosote build up. Stainless steel cannot solve that problem. You don't want to rob too much heat, or you get a problem with creosote build up.

I wasn't completely clear but the stainless steel heat exchanger is inside the firebox. You just need to drill 2 holes. Google it.

J Mozinski Hey J, are the holes drilled horizontally, or is one near the top of the stove and the other near the bottom? If it is the latter I guess there would be some convective rise through the loop, but it would be minimal. I recognize that internal coils do work very well, but if you are relying on a circulator pump for flow and the power goes out, you could potentially have a problem The point to the vertical coil outside the flue is two fold; First it gathers the heat progressively as the water goes up through the coil, and this creates a strong unpowered flow from the convective rise. Second by placing it outside the flue and insulating it, not too much heat is removed from the exhaust, and the flue remains clear and easily cleanable.

convectioncoil.com The holes are vertical - maybe 6 or 7 inches apart. My heat exchanger is just a horseshoe shaped piece of 3/4"ID stainless that's probably about 24" +/- or 48" if it were straightened out. It's considerably thicker walled and stronger than copper. You'd be surprised how much convection there is. I think the bigger the difference in temp between the in and out, the faster the water moves. There are also flow dynamics to consider. You know one 90 degree bend is equal to like 3 or 4 feet of pipe in terms of friction and flow restriction. I don't know about your spiral bends but just the sheer length of the 60 feet will definitely slow things down. Maybe that's good if it needs the time to gather btu's. Even if you have a heat exchanger in the firebox, you could still use the one wrapped around the exhaust to catch some of what's going up the chimney if you have a high exhaust temp. I don't have any circulator so power outages aren't a problem. I've been thinking about adding a circulator and another heat exchanger on the other side of the firebox [inside] in order to handle some radiant heat in the floor but I'll have to add another storage tank first because I only have 50 gallons now. Too much free hot water - such a problem to have, right?

J Mozinski Adding a circulator and an aquastat to control your woodstove loop will no doubt make a HUGE difference your system's overall performance J! Definitely do it, you won't be disappointed. Do you presently have an elevated storage tank? If not doing that even before you spend the cash and time to install a circulator pump would likely be advisable. That way you will be able to freely take advantage of both whatever convective rise there is in the vertical section of the internal piping in your stove, plus the external rise to the top of the storage tank. Between the two you should always be guaranteed some constant guaranteed convective flow and your system should stay safe and effective ...even when the power goes out! There is no doubt a bit of flow resistance by bending the 3/4 pipe into a 6 inch id radius, but I'd be willing to bet that one of my entire 29 loop Convection Coils has far less resistance than even a few 90 degree copper elbows. If you do need to use elbows it is good idea to use the long sweep 90s ((I did, quite a few of them in fact). They take up only a little more room but have far better flow. Most good plumbing supply houses have long sweeps whereas your local hardware "big box" store probably doesn't

Hola Nazael, Purtroppo hablo mui poco espanol. Por favor vist mi website para proyectos en; convectioncoil.com Gracias!

convectioncoil.com Hi, I am using a translator of Google ...... your site has excellent information, I have been helpful, soon shall begin with the construction of the system in my house. Greetings from Argentina

I've never tried it and don't think that this would not work well Don. First off, it would trap creosote in the crevices. Second, I'm not sure that copper would react well with the gases and acids in the flue exhaust. And finally, by having the coil outside the flue pipe and insulated, not too much heat is removed from the exhaust gases. In fact the pipe in that section is always just lightly sooted ans shows no sign of decay even after nearly three seasons of use

Won't work with just convective flow and I absolutely won't recommend it.

in that case wouldnt you just use a aquastat and recirculating pump?

This would work well enough Rob, but you would definitely want the pop off valve well figured out and plumbed just in case the power goes out. By using natural convection the flow never stops and the system is far safer

I have yet to build a website and form an official business, but do have coils to sell Jim

Two are 32" high 31 pass coils, and one is a 22" high 20 pass coil.

You said you still have some for sale? How much do you charge for them?

Hi Jim Yes I do still have a few of the coils that I had manufactured available. Pricing is $300 for the 22" high coil and $400 for the 32" high coil. This by the way is well under what I paid for them, but just about what I would like to be able to sell them for once I figure a way to make them. Unless there is a space constraint, I'd recommend going with the 32" for the extra heat gain. As you have noticed there are quite a few good ideas for heating hot water with a woodstove out there, but most fail in my mind in one key area... safety. By elevating your storage tank and incorporating thermosyphon the system remains safe even if the power goes out. It does work much more effectively with the assist of a circulator, but the flow through the 3/4 tubing is adequate to remain safe even without one. I'm located in New Hampton, nearly dead center in the Granite State. As I type this it is in the low teens outside, about 70 here in my office, and I have a load of laundry washing ...with all the comfort and hot water coming from the convection coil powered Steibel storage tank

Good eye Pleasecho2 I have since added a small expansion tank on the return line. The system seemed to work fine with just the 2 foot capped expansion line, but I did see the pressure pass 30 pounds a few too many times. If never caused a problem with the boiler relief valve but why risk it. The boiler relief by the way is vented all the way down to within a few inches of my concrete floor

Tamás Babos Please explain why

convectioncoil.com www.inspectorsjournal.com/forum/uploads/jim%20katen/200810444448_GrundfosManual.JPG

convectioncoil.com Axis 90° turn

Tamás Babos You are correct Tamas in that it is not an ideal placement, but the pump is both self priming and self purging. I believe that this is what the engineers are trying to achieve in the placement recommendations. The pump has been performing flawlessly for five seasons now.

Can you elaborate why please? The coil loop has a constant flow to the elevated tank due to natural convection, is circulated even faster by the addition of a thermostatically controlled circulator pump, has an expansion chamber, and finally is topped with a boiler pv valve that is piped to within a few inches of the floor. Please do share where you see a problem Kaoss53, maybe you could even share an improvement?? Thanks

by wrapping coil around a pipe and running water through it is keeping the pipe cooled more then its designed to, then you build large amounts of creosote. there are plenty of people that have thought of this. hints forth theres a reason why it has not been patented. Stove pipe is just not ment for that application. Over 40 years of wood stove, masonary and pipe experience. plus if ur insurence company saw that, they'd drop you so quick and if you ever had to make a claim they WOULD NOT PAY. insurence companys are asshole's. but if you plan on keeping it like that make sure you keep that pipe clean. Best of luck :)

Good concerns Kaoss53, but they have proven to be unfounded. The creosote has not been an issue at all, due in part I'm sure to the fact that the coil is externally insulated, and in part to my habit of running the stove open enough to bring the stack temp up over 450 or so once a day. Please read my other posts. Where my flue comes out of the back of the Fisher stove, I have a tee rather than the customary elbow. The bottom of the tee ties into a capped one foot section of pipe which I can easily remove for regular inspection. Looking up from that point shows the flue to be grey soot at the area where the coil is, but there is never any build up. The only area of my chimney that requires periodic cleaning is the outside cap, and to me that is normal and to be expected. I haven't considered a patent because a convection loop is actually a very old idea, I first saw it published in Mother Earth News in 1978. The trick is in forming sixty feet of 3/4 soft L to a snug 6" id coil ...without kinking it.

well if it works and you have no issue's i guess not much i can say against it. stay safe

Great thoughts Slawik! Thank you for sharing them. Are the thermal blankets as cohesive and flexible as fiberglass? I have found that the easiest way to insulate the coil was; leave the first two coils(nearest the stove) uncovered, wrap everything above it in a few layers of tin foil, wrap that with 2 foot wide R11 fiberglass, and once the outer sheet metal (not shown in the video) was clamped in place fill the void above the fiberglass with crumbled Roxul. The coils are 32" high, by using the method described the fiberglass never comes within 3 inches or so of the bare flue pipe, and only has direct contact with the outside of the liquid filled Convection Coil. Again for clarity, the layers from bottom to top are; two loops (3"0 of uninsulated coil, 24" wrapped in R11 fiberglass, and the top 5+ inches insulated with crumbled Roxul. The Roxul has an ignition point of near 2000 degrees, there has been no problem with the few inches I have topping the coil that are in direct contact with the flue. All said and done however, your recommendation is far wiser. I'll get a hold of some and change over to it before I post an installation video on my webpage. Thanks!

+Steve Foster I live in New Hampshire where the State motto is, Live Free or Die ;-) Seriously though Steve, code enforcement varies and luckily I'm in a small town where there is a bit more freedom. I built my small home entirely on my own but did try to adhere to code. The final inspection to get my occupancy permit was done by the assistant fire chief in my town and he saw no issues in the way I have my system set up. Now lest you think he was lax on details, I ran my own gas pipe as well and did have to dis-assemble some of it to replace one galvanized elbow that I had used when I ran short of black pipe. Apparently nickle with flake off when exposed to propane...