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Fire Place heat exchanger

steve z.
steve z. Member Posts: 11
My friends dad had a grate made of steel pipe in his fireplace, but had it piped back thru a 120 buffer tank to take the excess pressure and temp off the system. He never left it alone and if the fire was too hot he has a valve that allowed the water to blow off to a drain and add cool water to temper it back....watch it closely or you will have a runaway train.....


  • David Fowler
    David Fowler Member Posts: 1
    Heat exchanger for fire place to supplement hydronic system

    Gentlmen and Ladies,

    I have a steam boiler system in "this old house" in Detroit, to which I added a radiant floor hydronic system via a heat exchanger in the "Butham" boiler. Sucessful beyond my expections. (The remodeled kitchen is heated by the radiant system only. The remainer of the house is still on the steam system). Now I want to go one step futher and that is, burn wood in the fire place while piping the hydronic system thru a heat exchanger grate in the fire place. I have been unable to find a grate (made of tubing) to accomplish this experiment. The tubing companies want much $$$ to even talk to me. Help, David.
  • Keith_24
    Keith_24 Member Posts: 5

    Make the hearth grate out of steel pipe by bending it on an anvil. Make sure you control the loop so that the fire doesn't boil the water internally.

  • jp_2
    jp_2 Member Posts: 1,935
    fail safe

    what are your plans to make it completely fail safe?

    if the pump stops and the water boils then the pump starts again, what do you think will happen?
  • Weezbo
    Weezbo Member Posts: 6,232
    you should do some reading first, it will help you...

    to consider some of the variables within your current planned strategy. Look into Gravity heating systems and then go back in time a ways and check on the gravity boilers and the engineer's who designed them....Good Luck and Safe hydronic-ing.
  • mtfallsmikey
    mtfallsmikey Member Posts: 765
    Take a look

    On woodheat.org...some pics of some of these failed science projects.
  • Bob Harper_2
    Bob Harper_2 Member Posts: 54
    mixed message

    David, you speak of maximizing heating efficiency then you say you are going to burn an open hearth fireplace. That is an oxymoron. Regardless of heat exchangers, you are losing 400-600 cfm up the stack every minute. Air you already paid to heat. If you want supplemental heat in the fireplace room, install a gas, wood, or pellet insert and let the boilers heat the hot water. Don't you think enough people have been blown up over the years with DIY boilers and hydronics?

    If this was such a bright idea, don't you think major mfrs. would have marketed a system that is tested, listed and meets ASME and whomever else regulates boilers in your area?

    Think about it. Just friendly advice,
  • stevel
    stevel Member Posts: 25
    back boiler

    What you are describing was common in england and is called a back boiler, it is placed in the back of the fireplace and
    the hot water moves by gravity to a storage tank above the the
    fireplace to remove the excess heat, and then is pumped form there.
    they are still available as replacements.
  • Bob Gagnon plumbing and heating
    I built one

    a few years ago but if you take too much heat out of the fire you get a lot of cresote buldup on the heat exchanger and chimney. Someone told me the guy from this old house burnt his house down trying something like that, so I disconnected mine. The fireplace was sucking a lot of heat out of the house too. I put in a wood stove with a glass front, drawing outside air for combustion, installed radiant panels with aluminum plates in the walls and ceiling around the wood stove, and I circulate my radiant system without taking any heat from the boiler. The ceiling above the wood stove is 120 degrees and about 10 feet away it gets to 100 degrees, so the circulating radiant moves this heat from the warm part of the house to the cold part. It also stores it, because the heat from the wood stove is now moved to the floors, walls and ceilings in the cold part of the house, so the house is more even and I don't have to fire the stove as often because I'm not just heating the air. It acts like an external heat exchanger. Thanks, Bob Gagnon

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  • Bob Gagnon plumbing and heating
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  • gordon_9
    gordon_9 Member Posts: 1
    york gas furnace

    Is there a problem with the heat exchanger in a york gas furnace ---i had one leak carbon monoxide after 8 years of little usage installed in 1999
  • Rich Kontny_3
    Rich Kontny_3 Member Posts: 562
    The Two Bobs

    Make great sense,the conventional fireplace is very inefficient by itself,add the cooling of circulated water to the equation and you set yourself up for creosote problems. Compound this by burning very dry wood to avoid creosote and you increase temps to the point of creating pressure issues in the closed loop heating system that have to be addressed.

    My brother in law had a Tarm wood fired boiler put in a new house back in the late 80s he thought he could get away with a little less than seasoned wood (popple a hybid birch tree) The flames from his chimney fire were visible 6 ft. above his roof line. No damage to the house though because the chimney was well built (he is a mason!)

    There are better ways to extract heat than fireplace hearths.

    Rich K.
  • Couderay
    Couderay Member Posts: 314

    Better off starting new thread located at the top of the page
This discussion has been closed.