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Boiler questions. Tank size? Lifespan?

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by captonion, Jan 13, 2010.

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  1. captonion

    captonion New Member

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    Thinking hard on going for an atmos boiler, but have a few questions.

    I am planning on using a heat exchanger/forced air, for a 1500sq/ft new construction home.

    1. Recomended storage tank size
    2. Life of a boiler?
    3. Does the waterjacket surround firebox like the outhouse type.

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  2. Singed Eyebrows

    Singed Eyebrows New Member

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    Hi Captonion; Connecticut Green Heat has the Atmos manual online. This will give you tank size for the various models & they reccomend a large expansion tank. The mean life of the boiler is 10 years, same as the carbon steel Wood Gun. It can last longer or shorter depending on how you take care of it. You need to run boiler inlet protection. Preferably a Laddomat or Termovar loading unit. The water jacket does not surround on my GS model, not sure about the S. I know it doesn't because there are four 1/2" holes drilled in the sides of the GS. I almost had a heart attack when I saw this. I thought someone screwed up. They blow heated air horizontally across the fire in mine. These are good boilers. I believe a firetube type will capture more heat though, Randy
  3. Fred61

    Fred61 Minister of Fire

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    Please explain why, if this is new construction, you are installing a boiler and then running through a heat exchanger to hot air. In-floor or under floor radiant would be a better choice. You would be able to make better use of lower temperature water, lower electricity costs since you wouldn't be running a large fan and would eliminate bulky ducting along with a bunch of other issues.
  4. WoodNotOil

    WoodNotOil Minister of Fire

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    I tend to agree that if you are putting in a hotwater boiler, you should plan on radiant, radiators, or baseboard. Double the recommended btu output for zones and you will be able to use water temp down to about 120*. Add around 500 gallons of pressurized storage and you have a system that will go a while between fires... I know little about the Atmos compared to other brands, but the technology itself seems similar to other brands.
  5. Frozen Canuck

    Frozen Canuck Minister of Fire

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    Agree with the statements on using radiant heat instead of forced air for your building. I have a question/statement. You said this was new construction. If you are in the planning stages I strongly suggest you do some research into SIPs (structural insulated panels) for the construction of your home, this particular building system has come a long way in the past few years, much stronger than it was in the past, as an example I can, using this system, build a home that has R 90 basement walls, floors, walls & roof. That is with currently available products. Mass market stuff, you wont have to go to another country for supplies. We are doing this right now where I live, along with net zero homes, (homes that create as much or more energy than they consume). Yes, where I live we get - 40 every winter the only question is how long it stays. There are many different manufacturers & systems for SIPs some of which are very DIY friendly, 4'x8' panels, 2-3 ppl can build these, others are for the pros only, 8'x24' panels that are installed with a crane, the big ones are great for large projects. I suggest you look for the 4'x8' panel systems. I build for a living and I can vouch for the improvements made in SIPs in the past few years. No matter what building system you choose, think maximum insulation possible with that system as nothing will give you as rapid an ROI as insulation. As to what heats your home we all of course hope you choose wood. If you would like more info you can use the board or PM me, should be no conflict as you are way out of my service area. If you are in the planning stages of your home you have a lot of "choices" on your plate, my personal advice, think long term, very long term, as in a home that you could leave with pride to your great grandchildren. Just the opinion of a middle aged contractor that spent most of his life thinking outside the box. Good luck with your decisions.
  6. in hot water

    in hot water New Member

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    hydronic, "hot water " heat is a great way to go. Great for wood boiler and thermal solar input. A properly planned tank could accept solar and boiler inputs.

    A 3/4" pipe flowing 6 gpm at a 20 ΔT will move as much heat as a 14X8" duct pushing 130 °F air at 1000 fpm! And the duct will have 10 times the heatloss.

    A home that size, tightly built could use as little as 10 BTU/ sq. ft or a total design day load of 15.000 BTU/hr. A buffer tank will be a good investment with loads that size and a fraction of that load on less than design days.

    In many cases it could be heated with the occupants (400 btu/ hr output), lights and appliances.

    Low temperature radiant floors, walls or ceilings as a 1st choice, panel radiators 2nd.

    You will want some air movement, that is where an air handler works best. It also allows cooling, and the ability to add or remove humidity. at least look into heat recovery options if you go straight radiant.

    Plenty of great products on the market these days, hard to wade through all the choices.

    hr
  7. captonion

    captonion New Member

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    The reason I am going this route is that the house is already built. Just need some imput!
  8. twitch

    twitch Member

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    If you are going to do storage with a hot air exchanger system, I would definitely go with pressurized storage. I have a Tarm Solo 30 with an air handler, no storage, and it needs water temps above 160 to get good hot air in the house. It could be that the HX in the air handler is too small, but it is rated at 100,000 btu. If I were to put in storage, I'd probably go with 1000 gallons +/- from reading other posts here on that subject.
  9. bupalos

    bupalos Member

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    I've got the S and I guess I misunderstood this. I thought the GS was just the S with some extra ceramic insert, and when I looked at that I thought "well the tar is just going to sneak in between the ceramic and metal and condense anyway and maybe be worse yet." But you're basically saying it's an insulated woodstove above the flame and a boiler below? That makes way more sense I think. There aren't any holes in the upper portion of the S, and I do think there's water behind those walls. I thought it was needed to control the temp of the upper chamber and keep the wood charge from gasifying too rapidly.

    I second the opinion that the Atmos does seem very solidly built, with pretty thick steel. I still don't have mine hooked up, but all the feedback I've collected has been good. Lots of happy users in the UK. Rated for 10 years, but I'd bet if you size big storage and can always run it full out, it's going to be significantly more than that.
  10. Singed Eyebrows

    Singed Eyebrows New Member

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    I'm told they went to the GS mostly for emissions. It would be interesting to know if there is water behind the primary chamber walls in your S boiler. I believe my GS has water at the lower primary chamber walls right behind the ceramic. The S & GS nozzles are the same. The smoke path in the lower chamber is different & the GS forces the gasses to go along each side of the water walls. The S I believe transfers heat at the bottom water wall. the heat exchanger is probably the same & my opinion is it could have a bunch more surface area. Atmos was built to a price though. Mine was built to EN303-5 , certified welders,dye penetrant checked welds etc etc & also TUV certified, so the quality is there. The glaring shortcomming for me is the heat exchanger though, Randy
  11. WoodNotOil

    WoodNotOil Minister of Fire

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    Ideally you would oversize the HX in order to be able to heat with water below 160*. All the same, I agree that pressurized would be the way to go since you can get the water much hotter...
  12. pybyr

    pybyr Minister of Fire

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    Water-air HXs are generally given BTU ratings based on 'normal hydronic' assumptions of water at or near 180 F; to get good heat out of cooler water, you need to "go overboard" on a water-air HX. I got mine from Nationwide coils, which helped me run parameters of various water temps and airflows. I was pleased wth their service and very pleased with how well the HX works. The new 'outdoor furnace supply' that is advertising here on Hearth apparently also has some relatively large HXs.
  13. captonion

    captonion New Member

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    So no clear answer to my questions then?
  14. hkobus

    hkobus Member

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    There are so many options out there and in your mind you have a good understanding on what your situation is and what your preferences are. That is hard to get a good concise answer to. I think you need to have a look at your situation and all the variables like the fact the house is build what is the heat load (first step in determining boiler output), how often are you able(willing) to load or tend to a boiler ( this may help decide on storage size) What is the budget, are you installing it or contractor.

    As to live span, I think there are many post here suggesting that 20 years is not an exception, but that may depend on use and brand. The more modern euro boilers have not been around that long but are based on older models. Electronics may be more of an issue over time than the actual boiler.

    Your #3 question will depend on the brand, there are many variations to the concept with HX tubes and water flow directions.

    I know my ramblings may not help you either, I just found when I was in the process of choosing a system that I considered my options and combinations. One of the first things I needed to decide if I was going to process or handle wood for the lifespan of the boiler after that I just worked through it and asked the questions when needed here. All of the above have many valid ideas and facts, to you the task to match it to your life.

    Good luck and have fun, it may become an addiction :lol:
  15. captonion

    captonion New Member

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    Last year my house burned, but the basement was not damaged ,so the new house was built on that. My old house had a forced wood furnace that used 8-10 cord a year kept well above 70. The new house is better isulated with excellent windows.

    I have a friend who is a plummer/furnace guy. He has never installed a boiler, but said he will do it for me.

    The reason I asked about storage tank size, is I read on here that tank size is very important to run a boiler efficiently, and is in dirrect relation to how wood hungy the boiler will be.



    Right now the new house has forced air propane. I did have a chimney installed during consrtuction, but now I am wondering how to utilize it.
    I very much enjoy cutting my own wood(hard maple), and I do that for free! I am just intrigued by these gasification boilers. Thats why I an fishing for info on here.
  16. Singed Eyebrows

    Singed Eyebrows New Member

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    As a number of people on here whos opinion I respect have said, Running storage is not for efficiency, it is for convienience. The bigger the tank the longer you can go between firings & you can burn when you have the time. There is no efficiency difference between a gasser running flat out into a heat exchanger with no storage & a gasser running flat out into a storage tank, whatever size, Randy
  17. captonion

    captonion New Member

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    If Tank size has to do with how often the unit has to be fired, that is what i want to know. How wood hungry it is going to be means alot for efficiency IMO. If a storage tank makes the difference from 8 to 20 cord a season, thats what I want to know.

    I admit I am green at this, but willing to learn, and you can't learn without asking questions.
  18. Singed Eyebrows

    Singed Eyebrows New Member

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    A storage tank isn't going to make the difference in using 8 or 20 cords a year. Lets say that you burned 3 fireboxes full of wood to heat a tank & this heat will last for 24 hours. Or you didn't have a tank & you burned 3 fireboxes full of wood constantly heating a heat exchanger for 24 hours. You used the same amount of wood. You had the same efficiency. I'm not sure we are on the same page with the word "efficiency". In short, you are not going to save a bunch of wood by running a tank, Randy
  19. karri0n

    karri0n New Member

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    Unless you oversize your boiler, and get lots of idling, that is. An idling wood gasifier has far lower efficiency. Oversizing(to an extent) is an advantage when you have a fair amount of storage. If your boiler perfectly matched the heat love of the building, you wouldn't be producing any excess btus to put into the storage tank.

    For the short answer to your question, most people tend to use 500-1000 gallons for storage, but it's really quite a bit more complex than that. you need to calculate your heat loads before determining anything else. The fact that you're using forced air means you will want to be utilizing MUCH hotter water, and pressurized storage might be the way to go in this case.
  20. hkobus

    hkobus Member

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    Singed, Captioned,

    Randy, I was just going to say the same. I have run the Eko for almost 3 seasons with minimal controls and no storage, building fires of the right size in the shoulder season and running full boar when needed and reloading 3-4 times a day. Efficiency is not much of a difference in my mind, convienience is my reason for adding the storage at this time. My budget is also better today than 3 years ago.

    That is good info on the house, I would look at the heatloss of the new situation and size a boiler. Then you may find managing the boiler without storage ok when using propane at night when called for. ( I have had no backup heat, but will next week!) The incremental cost for the storage may be more than economical feasable, then again with an air handler you have no themal heat retention like with infloor radiant (was my storage over the past seasons)

    So you are not bothered with cutting and stacking, then my only question left at this time is: Is this a good time to get the wood (find the gassers have some smoke issues, more than the Newmac's I used over the years) and smoke mess out of the house and have the boiler in an outbuiling of some kind. This is the way I went and don't regret it. The storage is in the basement and is non pressurized.
    Continue fishing, it is the right thing to do before you spend the money.

    Henk.
  21. captonion

    captonion New Member

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    Going pressurized was my intention, with a well insulated vertical rectangle tank.
    From what I understood once the water in the tank was hot, is was easily kept there without running the boiler full out.Hence the unit would use less wood in the long of it. I am wrong?

    The reason I wanted to go with an inside boiler, is my township put a ban on the outside models. I also like the idea of far less smoke with a gassification boiler, than a regular wood stove , or furnace.
  22. Singed Eyebrows

    Singed Eyebrows New Member

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    You don't get something for nothing. The water might be easily kept hot if you are drawing little heat from the tank. If you are drawing lots of heat you will need to put this heat back in. With storage you want to run your boiler flat out & this is the most efficient way to burn, you will burn less wood this way. With a gasser you should not get creosote in the chimney & this is one of the big advantages.
  23. captonion

    captonion New Member

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    As I said my house is very well consructed (above code). It doesn't use a hell of alot of propane, but wood is free! Even tough the wood is free, I would like to use the least amount possible to heat it.
    I just read that the gassification boilers are way more efficient which means it should use far less wood to do the same job than a forced air wood furnace. I would like to hook it up in a way that it will burn the least amount of wood right off the get go. This is why I am asking so many questions.
  24. hkobus

    hkobus Member

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    It sounds like you know what you want, that is a good thing. Main thing now is to select a boiler and to get the best efficiency size it to the heat load, or a little smaller and use the storage for buffer when extra is needed and the fire the boiler at full rate for best results. A larger boiler will cost more $, more mass to keep at optimal temp(gasifiers need to "cook" the wood to make the gas and this is best at optimal temp around the 65 °C or above) running less than this reduces efficiency too.
  25. Singed Eyebrows

    Singed Eyebrows New Member

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    We try to help. You were comparing efficiency with using a storage tank or not & I didn't believe there was much difference. You are comparing a gasser to a regular wood burner & there is quite a difference. Even my old Energy Mate boiler was rated at 50 percent eff. by the manufacturer & I don't think most forced air furnaces exceed this. My Atmos boiler is rated about 85 to 88 run flat out. I don't blame you for wanting to get the most out of the wood you cut. If you can afford a gasser that is the way to go, Randy
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