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Sizing new boiler

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by jrod770, Nov 3, 2013.

  1. jrod770

    jrod770 New Member

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    I have decided to go the gasser route as opposed to a OWB. I have done heat loss calcs for the house, it came out at 43,985 btu/hr. I would also like to heat domestic hot water and eventually heat a 1200 sq ft garage, where the gasser will be located. What size eko do you think I should go with, the 25 or the 40? I will be going with storage,it will be located inthe garage with the gasser, about 35' away from the house. Any suggestions on storage size as well? Thanks for the help.

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  2. Clarkbug

    Clarkbug Minister of Fire

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    How much space do you have storage for? I would go with a minimum of 500 gallons, although lots of folks like to have more and shoot for 1000 gallons. If you have the space and funding, go for the larger sized boiler and larger storage. That way you can fire the boiler without any idling, charge up your storage, and not need to fire it again for a day or two.
    BoilerMan likes this.
  3. Floydian

    Floydian Feeling the Heat

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    Good job running the heat loss calc on the house-sounds like a solid number to me for the construction of your house. Now you should figure the heat loss for the shop as well to get your worst case number.

    I like the idea of sizing the boiler to storage. Either the EKO 25 or the 40 will be oversized most of the time but the 40 would have more capacity to cover the heat load as well as supply more heat to storage. Sizing storage to your wants/needs is largely determined by the lowest usable supply temps your heating system can utilize.

    If you need 160::F+ to heat your house then a smaller amount of storage acting more like a buffer tank might make more sense. In this scenario the EKO 25 with a couple hundred gallons of buffer could work well but would probably require some less than convenient loading of the boiler as you will be keeping a fire going for longer periods of time with a smaller firebox.

    Now if you can use water down below 140::F , larger storage could offer you more convenience with more time between firings and allow you to fire when you want to instead of when the house wants you to. In this scenario I would opt for more storage and a larger boiler output could work better, covering the heat load as well as recharging storage at the same time.

    You have forced air heating, right? If so sizing your water to air heat exchanger for the lowest possible supply temps that can keep the house comfortable will be important. I would size it for less than 140::F at design temp if possible. Basically the lower the better so you can get more out of storage.

    That is how I see anyway (if that all makes sense),

    Noah
  4. jrod770

    jrod770 New Member

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    Storage space isnotan issue. I was thinking eko 40 with around 1000 gallons of storage. Sound like overkill?
  5. jrod770

    jrod770 New Member

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    Floydian, you posted as I was typing the above. I'll run calcs on garage as well. Yes, forced air furnace in house on propane/heat pump.
  6. maple1

    maple1 Minister of Fire

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    No.
  7. jrod770

    jrod770 New Member

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    Garage construction not as air tight as house. Heat loss calc for garage is 39,377. I'm not planning on heating it all of the time, just when i'm out there working.
  8. nrcrash

    nrcrash Member

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    Sounds like it would be a very covienent system for you, where you could light your fires when you had time too instead of when you needed too. I wish I had a 80 with 2000 gallons of storage!
  9. Coal Reaper

    Coal Reaper Minister of Fire

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    I wouldnt go any smaller. Youre on the right track brother!
  10. wardk

    wardk Member

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    With that boiler and storage installed it should be all the heat you need in the garage.
  11. jrod770

    jrod770 New Member

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    That would be nice if I didn't have to put in any additional equpment for garage heat. That way I can get rid of both the add on in the house and the one in the garage.

    If I didn't go with the Eko 40, what other equivalents are there? What are your favorite options to the Eko?
  12. Clarkbug

    Clarkbug Minister of Fire

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    There are LOTS of options in that size range. I have a Varmebaronen 37, they have a model that has lambda that is in the same size range. There is BioMass, WoodGun, Effecta, Econoburn, Tarm, Froiling, Attack, Paxo just to name a few. They all have their pros and cons. If you have space in the garage, you could go Garn Jr. and that is your storage and boiler all in one!
    Coal Reaper likes this.
  13. jrod770

    jrod770 New Member

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    Yeah, that was my fear. Too many choices, thus resulting in more hours pondering the pros and cons of each unit. What is the price range of the Garn?
    Coal Reaper likes this.
  14. JP11

    JP11 Minister of Fire

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    Not much different than a boiler, storage and plumbing.

    I didn't want the garn due to unpressurized... but it's a simple solution.

    A bigger boiler with storage will be able to supply your loads, AND charge storage at the same time. Very handy. You can add a door or something similar to adjust the amount of heat you allow to "leak" from your storage to heat your garage.

    JP
    Coal Reaper likes this.
  15. Clarkbug

    Clarkbug Minister of Fire

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    I would say its easiest to figure out what your budget looks like, and let that help you decide. There are features of each unit that set them apart. The lambda boilers have controls that help compensate the air for different stages of the burn or different moisture contents within your wood. Good for squeaking that extra bit of efficiency out of a system.

    I picked mine because I can clean it from the front easily, and it was pretty light, so easy to get into my basement. You could have different features you like or dont like, and that might help make your decision for you.
    Coal Reaper likes this.
  16. Coal Reaper

    Coal Reaper Minister of Fire

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    I bet i spent more time researching my boiler before i bought it than i did my house. And now i still spend too much time on this site.
    Runner T likes this.
  17. maple1

    maple1 Minister of Fire

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    I am fully picking up what you are laying down there.
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  18. wardk

    wardk Member

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    I have my boiler in a 10x 20 shed . r 30 on the boiler and the shed and its still 80 in there under full fire.
  19. jrod770

    jrod770 New Member

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    With my heat loss calcs, do you think I could get by with an Eko 25 and 1000 gallons of storage? That new, low price is very tempting. What is the downfall of sizing the boiler too small?
  20. maple1

    maple1 Minister of Fire

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    More frequent firings/loadings, longer time to charge storage. Simply, it will have to 'work harder' than a larger one - but that may or may not be a big concern depending on your heat load.
  21. Clarkbug

    Clarkbug Minister of Fire

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    Similar to what Maple said above, if your boiler is too small, when you are at your design load the boiler will be firing just to meet heat losses, and you will have a difficult time charging that much storage. Not a big deal if you are around to feed it, or if you are charged up ahead of time.

    My personal preference would be to lean towards the 40, especially if you have the 1000 gallons of storage.
  22. maple1

    maple1 Minister of Fire

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    Personally, I would also go bigger (said without knowing the $$ difference). With the bigger unit you can more fully utilize the burning flexibility potential your storage presents.

    Your daily routines will also be a factor - say if nobody is home during the day, you could load the 40 up before you go to bed in the evening & not have to burn until the next evening. With the 25 that might not always be possible. Lots of considerations, lots of options.
  23. stee6043

    stee6043 Minister of Fire

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    If I had it to do over again I'd personally go with an EKO 60. My house could easily be heated with an EKO 25 based on the math, similar to yours. With storage, the EKO 40 makes perfect sense. But I'll tell you what, I many times wish I could heat my storage a little faster or perhaps with one less trip downstairs during the peak season. I haven't run any hard numbers on the 60 but I suspect I would be able to get a good fire burning and probably run with a single full load most evenings.

    With storage there is no downside to over sizing the boiler other than cost and perhaps footprint.
  24. jebatty

    jebatty Minister of Fire

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    I have a Tarm Solo Plus 40, calculated heat loss around 35,000 btuH, actual normal demand level around 15,000 btuH, 1000 gal of storage and it is great. Only have to fire the boiler about 4-6 hours once every other day during the worst of winter. I would go with a boiler rated around 140,000 btuH as a minimum. Give you lots of flexibility.
  25. jrod770

    jrod770 New Member

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    Thank You, that was the info I was looking for.

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