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My homemade outdoor wood furnace (boiler)

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Lapeer20m, Oct 17, 2013.

  1. Lapeer20m

    Lapeer20m Member

    Joined:
    Oct 17, 2013
    Messages:
    81
    Loc:
    Michigan
    Just wanted to say that things are going great! The boiler works better than I expected. We had a bit of a cold snap and there were no issues, the boiler kept burning easily with loading at 12 hour intervals.

    This morning was below freezing but highs are going to be near 50. On days like today I like to start a fire and heat the house using only sticks that I pick up off the ground within about 100 feet of the boiler. I can just let this single load of sticks burn and it'll heat the house all day. I'll start another fire after dark. This way I save my processed wood for when its actually cold out.
    Vizsla likes this.

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  2. McKraut

    McKraut Member

    Joined:
    Sep 1, 2011
    Messages:
    243
    Loc:
    South Central PA
    Congratulations on your success. Now that you're done, I could use some help........Michigan isn't that far away.

    Bob
  3. Lapeer20m

    Lapeer20m Member

    Joined:
    Oct 17, 2013
    Messages:
    81
    Loc:
    Michigan

    I installed the dhw sidearm yesterday. It works great, but not sure if I plumbed it correctly.

    Thermosyphon action is improved with higher owb water temps, so I circulate water first through sidearm then to the heat exchanger. My concern is that when it really gets cold outside this may make it more difficult to keep the house up to temperature.

    It would only take about 10 minutes to swap the pex fittings around to feed heat exchanger first then the sidearm...

    Today has a high of 50, then I don't think we will be above freezing again for the foreseeable future. After the weekend I should have a good idea if this setup is going to function properly.
  4. McKraut

    McKraut Member

    Joined:
    Sep 1, 2011
    Messages:
    243
    Loc:
    South Central PA
    Did you make your own sidearm or did you buy it?

    Bob
  5. Lapeer20m

    Lapeer20m Member

    Joined:
    Oct 17, 2013
    Messages:
    81
    Loc:
    Michigan
    I made my own. I used 3/4 for dhw and 1" for owb.

    I wanted larger outside diameter but felt it was cost prohibitive and difficult to obtain as Home Depot doesn't handle any copper larger than 1".

    I suppose it would be possible to make one utilizing dissimilar metals but I did not explore this option.

    I'm still thinking about also installing a small plate exchanger into the dhw system just to make sure the mrs doesn't run out of hot water.
    Vizsla and hobbyheater like this.
  6. Lapeer20m

    Lapeer20m Member

    Joined:
    Oct 17, 2013
    Messages:
    81
    Loc:
    Michigan
    Just wanted to post a photo of the snow covered insulated culvert which houses my owb pex lines: It's nearly 30 degrees outside temp today. Water temperature is about 170 degrees.

    [​IMG]
    Vizsla, rowerwet and brenndatomu like this.
  7. Lapeer20m

    Lapeer20m Member

    Joined:
    Oct 17, 2013
    Messages:
    81
    Loc:
    Michigan
    We've had near record cold, like most of the country. Many mornings bow freezing, the coldest: -20f.

    The boiler keeps up just fine as long as I keep it fed. It vaporizes hundreds of pounds of firewood in a 24 hour period when its below Zero.

    Today I swapped out the actuator for the draft control. It was damaged by a piece of falling firewood and ended up causing a boil-over.

    To reduce the chance of future boiling events I installed a new temp controller that will turn on the circulator in the house when the water temp reaches 190*. This should also serve as an "alarm" to alert us that there is a problem.
    Vizsla, stayfitz and hobbyheater like this.
  8. GENECOP

    GENECOP Member

    Joined:
    Jan 31, 2014
    Messages:
    240
    Loc:
    Ny
    Awsome project......well done, and you did the entire job for what my Fluepipe cost.....LOL...
  9. rowerwet

    rowerwet Minister of Fire

    Joined:
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    Loc:
    Merrimack Valley, MA
    that is when you know you did it the right way!
  10. Would you like some Tea?

    Would you like some Tea? New Member

    Joined:
    Aug 3, 2014
    Messages:
    10
    Loc:
    Missouri
    As far as freezing goes: I was involved with a big commercial project with a 100 ton fluid cooler on the roof. This thing saw 0-10F temperatures all winter, didn't freeze up due to circulating water. All the pipes are directly outdoors, uninsulated. They were gonna put the glycol in it about the time the hotel opened. But then some knucklehead turned off the breaker to the pumps on Friday night when the temperature dropped like a hammer, no glycol. Monday, $135,000 worth of fluid cooler scrap metal was sitting on the roof with 1000 pinhole leaks. No circulation = freeze.

    Moving water in insulated pipes won't freakin' freeze, frozen waterfalls notwithstanding (waterfalls are notoriously uninsulated). Stagnant water in uninsulated pipes will freeze right now.

    Now, I've had wellhouses in the country for years, heated by a light bulb, never froze. If your stove is in a tight little insulated house, it may not take more than a light bulb to keep it from freezing. Your buffer tank? Forget it, it won't freeze if it is insulated and you are using it regularly. If you aren't, leave your pumps running. Your pipes? Insulate them well enough, and they'll be fine. Keep the circulators running if you are off at grandma's house for Christmas. Heat tape them if you are paranoid. Go to a farm store and get a horse tank heater and throw it in your storage tank, if you are even more paranoid, when you are not firing the stove. If you insulate the whole system well, and add just a bit of heat or circulation, it won't freeze outdoors.
  11. Lapeer20m

    Lapeer20m Member

    Joined:
    Oct 17, 2013
    Messages:
    81
    Loc:
    Michigan
    We saw the longest coldest winter of my lifetime last year with temperatures below -20f and had no freezing problems.

    This year I am upgrading to alpha 2 pumps which are up to 20x more efficient than my current boiler pumps. I plan to run these pumps through a UPS power supply that will automatically transfer to battery power in the event of power failure.

    We went 5 days with no grid power with temps near zero last December. This sort of thing always seems to happen when I'm at work or otherwise not available. The ups will give me a window of time before I have to worry about starting the generator.

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