New guy looking for ideal system

duncanheat said:

Hello there. I love all the information you guys are honestly giving. I’m in the market for a wood boiler but I wanted some opinions on which one would a good make and model. I have a 3000 sq. ft. built in the 1910. I’ve been reading comments on GW and EKO and I’m concerned about the GW cracking inside but I really wanted to have an inside boiler. thanks for any help…

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Welcome to the forum and to the boiler room. Do you heat with wood already, or is this a whole new direction for you?

The EKO boilers are for designed for inside installation, although some people are putting them in outbuildings. I have an EKO 25 living happily in my basement. Pictures and system description on my site - link in my signature below. Several other people here have EKO and other boilers installed indoors.

duncanheat said:

Thanks. I installed a high efficient oil boiler a 3 years ago to replace a 30 year old one but now with oil prices so crazy I want to go a little greener. I have 5 acres here and my father has 70 acres of free wood (minus the labor) so this is the direction I want to go. My father recently put in a wood stove with a blower in his 1500 sq. ft. house and has cut his rice coal in half. With the wood boilers I've been researching I need some pushing in a certain direction to commit to the high initial cost. I was wondering if you guys have any ideas of what a great new system would be?

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'Great System' means different things to different people. A big initial decision is whether to go with a gasification system or not. The gasifiers are more expensive and a bit more finicky in that they really like dry wood. The payoff is much lower wood consumption and virtually no smoke or fumes. The higher initial cost may pay back in reducing the amount of time and effort spent dealing with wood.

Heat storage is another tradeoff that you will find a lot of discussion about. Heat storage allows you to maintain a steady house temperature without having a fire going all the time. It also allows the boiler to operate in its most efficient flat-out mode.

Radiant seems to be the method of choice for heating the house if you have that option. It provides very even heat and allows much more effective use of heat storage.

Dozens of other tradeoffs - I'm sure others on the forum will chime in.

I'm happy with the EKO 60. That's probably more boiler than you would need. I'm thinking a 40 would be about right with what little information we have to go on. You should really do a heat loss calc on your house, or at least use your existing boiler for comparison. Hot water storage gives you flexibility in sizing, so that you can either go too small or too large and still run the boiler at its optimum efficiency, which is what we are all trying to do.

So to me, the ideal system would be a gasifier with a good-sized storage tank (1,000 gallons or more). You can price and spec out the EKO 40, the Tarm Solo 40, the Econoburn and the BioMax 40 and try to narrow down your options. Wood size is one thing to watch. I got the EKO mainly because it would take 24-inch wood, while the Tarm only takes 20, and all my wood was longer.

Do you have a separate Class A chimney to vent the thing out of? If not, you'll either have to put one in or powervent your other boiler and use that chimney. They can't share.

Having unlimited free wood is an excellent place to start. You want to get far enough ahead so that you're always burning wood that's been cut and dried for at least a year--preferably two. Then you can just crank up the heat and relax. And don't forget the free hot water--year around if you have a storage tank.

I don't think so. I've never heard any horror stories about any of the brands I mentioned. The heavier-built units tend to cost more. Tarm has a 20-year warranty, compared to 5 years for the EKO. I don't know about the others. I think they'll all last a good long time if installed and operated correctly.

If you've got free firewood and you enjoy cutting it like I do, imagine the payback over the life of a gasifier. Plus, your house will be a lot warmer than if you heat with oil, because you're always going to keep the thermostat below 70 when you're buying oil by the gallon. With wood, if you look at it as an opportunity to get some exercise, it's already paid for itself by the time you toss it in the boiler, so why not turn up the heat a bit? So quality of life enters into the equation as well.

Anyway, we've got users of most of these boilers on this board, (and we like talking about it), so you should get a pretty good idea what you want/need by hanging around here and asking questions.

There are plenty of Greenwood threads here, and several Greenwood owners. I can really only speak to the EKO, since that's the only one I've ever used.

The Greenwood/Seton/Black Bear/Adobe design relies more on refractory mass than water for heat retention and storage around the boiler. The others use water. So you've got two different designs producing essentially the same results. The Garn is kind of in a class all by itself.

As I went thru the different MFG it seems to me if you are installing indoor or outbuilding makes a difference the ones using refractory mass would not be as productive outside as inside where they would release heat to your indoor space and the other types would be ok in either case. I decided to go outbuilding to avoid hauling wood inside, along with the smoke and risk of fire.

I ended up with a GW. I almost bought a Tarm, but their manual freaked me out about overheating (Closed system versus my open system GW). Honestly, if quality of wood was not an issue, I would have found a way to import a Viessmann.

I think the advantage of the refractory mass is that you can use 'wetter' wood. As long as it is up off the coals, the large heat mass will send the excess moisture up the chimney, so that by the time the dried wood makes it to the coal bed, it burns hot. Obviously, this is not as efficient as burning better wood.

I believe a large factor in the decision making process between refractory/natural aspiration and forced induction is a realistic assessment of your wood supply.

Jus' my two cents ;-)

I'd say putting it in the other building is probably just about ideal. At least from my point of view. That's how mine is set up. I was thinking this morning that if my boiler were in the basement, I'd operate it differently. Now I don't worry about smoke when I'm loading it up. Obviously, you don't want smoke in your house.

But that's a separate issue. Running underground pex is not a problem. It's a good place to put your water line. You can DIY the installation or buy pre-sealed/insulated supply and return assemblies by the foot.

Don't get hung up on the hot water storage. It's really good to have with any gasifier, but you can run without it and always add it later after you've seen how the thing operates and what your needs are. My house is all cast iron radiators, too. You get a little bit of storage there, because there's so much water in the system and combined with the cast iron, it holds some heat. I guess my point is that it takes some time to learn and appreciate how a wood gasification system works, and you can better tailor your heat storage to your needs once you become familiar with it. JMO.

And I heartily second ISDBTU's recommendation on making a "realistic assessment of your wood supply." That's an excellent point. You're going to need an adequate supply of dry wood to get the full benefit from any gasifier. It's not something you can conjure up quickly in most cases. It takes some planning--"realistic" planning. Well said ISDBTU.

Is the house above the basement going to be heated? If not, then I would put some extra insulation on the boiler--especially to keep it from freezing if it goes down. You'd probably want to consider using heating system antifreeze in that case.

Depending on the size of the boiler you get, you can go 1-inch or 1 1/4, for primary piping, I think. If necessary, you can go bigger, but it's probably not necessary. They sell complete assembled lines that include both supply and return lines insulated and sealed into pvc drain pipe. You buy it by the foot (it's not cheap). Or you can buy the pex yourself and then insulate and waterproof the line. People around here have done that, and it works well. I haven't. Connecting to your exisiting system shouldn't be a big deal. You can design the piping strategy to do different things. That's one of the beauties of hydronic heating systems.

There's a conversion chart around here somewhere that will tell you how many gallons of oil in a cord of dry wood. Or Google it. You have to factor in the efficiency of your boilers (both oil and wood should be more than 80%). That should tell you roughly how much wood you can expect to burn. I'd round up by a few cords, just to be on the safe side.

From what I understand so far they sell several different types of insulated pipe, I installed some stuff called Logstor it has 2 - 1" pex tubes covered with a foam insulation and then a plastic like water / utility pipe cover over that for an overall size of about 4.5 inches. The stuff is pretty tough I used a logging chain, winch and my 4 wheeler to pull it in and it was quite a chore. There are some other preformed types types some I looked at on the auction sites looked a little questionable to me for the price with reg pex plus a little bubble wrap and a drain pipe for about 10.00 a foot ??? Some installers use pex and then insulate it in the ditch with spray foam. If your run is short you can even just run a couple of pex lines thru a 4" drain line and seal the ends. Like Eric says if the pipes can freeze some antifreeze is in order it runs something like 65.00 per 5 gal bucket. BTW good luck with coring a hole thru 18" of concrete I would consider hiring that job out.

Here's a chart from Econoburn comparing the btu values for wood vs. oil, gas, coal, etc.

http://www.alternativefuelboilers.com/faq.htm#faq2

I'd stay away from the pre-insulated underground pex
IMO the pips are too close together
They will probably try to equalize their temp on long runs

Ummm . . . . .

where did that come from? I don't even remember this thread, and I'm not as old as say, Jags, or Dennis . . .

Inside, Outside, Storage, No Storage. Lots of Pro's and Cons.
First of all, how often will you be available to put wood in the boiler, and how much heat load will you have in January and February. I've heated with wood my whole life, with everything from an old wood furnace, box stoves, catalytic stoves, a Russian style masonry heater, and now a Frohling 40/50, with 1000 gallons of water heat storage. I would have to say that the Frohling is the easiest to operate of the whole bunch. I have always had wood in the cellar (basement), and can't imagine getting dressed up to go check the boiler before bed. Even though I am home on the farm a good part of the time, I don't want to deal with having a boiler outside.
Start comparing similar boilers, and get pricing. If you are handy, you can do most of the setup yourself. Different dealers price things differently, so be sure to price what you will actually get or want. If you can get up to Lyme NH, Tarm Biomass has a nice selection of boilers set up for demonstration. They will not retail, but will give you a list of retailers in your area. Good luck in your search. Don't get too hung up on one brand of boiler, but be sure it will do what you need, because a good boiler is a long term investment.

Greatest "bring back the oldest thread" thread ever

To be honest I am a little irked that this 3 year old thread got 3 new posts and my simple question about copper pipe heat exchangers was not answered once.
I had decided that I need to make more of an introduction of myself and project so that will come soon.



Erik

Maybe I don't know anything about copper HX??? :smirk:

Erik Akia said:

To be honest I am a little irked that this 3 year old thread got 3 new posts and my simple question about copper pipe heat exchangers was not answered once.
I had decided that I need to make more of an introduction of myself and project so that will come soon.



Erik

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To be honest the "how much heat exchanger do I need" is a tough question... Lots of variables, and I think many including myself use the guestamate method... Just throw
some copper coils in the tank and hope it's enough. If I were you I would dig through as many old posts as possible, And check some sites like the stss tanks. I think Tom from Maine
builds custom tanks, maybe check with him.

I am currently using 2x 100 feet of 3/4 inch L copper... 2 coils in parallel. It handles about 100-120 kbtu with the boiler output of 30 degrees higher than storage tank top temperature.