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    Buffer tank (16 Posts)

  • unclejohn unclejohn @ 1:59 PM
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    Buffer tank

    I'm tring to use a 50 gal electric water heater as a buffer tank for my hi eff. boiler. I have removed the elements and I can't get the 1 1/4 male adpter to tighten up snug. I have used 6 wraps of tape and dope on top of that. Any suggestions?
  • zacmobile zacmobile @ 6:45 PM
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    permatex

    Permatex 51d, let it harden up before throwing pressure on it as per instructions. It's ugly stuff but i've used it on sloppy threads with good results.
  • hot rod hot rod @ 8:28 AM
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    straight thread

    most of those elements and the port are a straight thread. The seal is intended to be the rubber ring gasket. You could add a large flat washer and use the ring the is on the element.

    Loctite 272 works well also. All the brass straight threads we assemble are sealed with loctite. Either 272 or 545 will work. 272 is thicker and not as runny.

    That should be a 1" thread, you can find a 1" MIP X 1-1/4" copper adapter, to increase at the tank.
  • Wayco Wayne Wayco Wayne @ 9:35 AM
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    Which way

    do you recommend using a buffer tank with a mod con boiler? I've installed them in series to ensure a low return water temp. In parallel I suppose it would work OK as long as the outdoor re-set is set up nice and low. But you'r have to use an extra circulator.
  • aemeeich aemeeich @ 6:11 PM
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    Buffer Tank

    This is what I did last winter when I installed my Knight / buffer tank. 

    I used PC-7 2-part epoxy, and then painted over everything after it cured.

    I piped the buffer tank in parallel with the boiler across the closely spaced T's.  That way I could just turn off the circulator to "remove" the buffer tank from the system if it wasn't needed.

    The Alpha feeds the zone valve manifold, and the 15-58 feeds the buffer tank running on low speed.  The other set of closely spaced T's is for my previous Vaillant oil boiler.  I left it hooked up and ready to go if I ever needed to run it again. 
  • SWEI SWEI @ 10:27 PM
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    buffer tank in parallel with the boiler

    Would you mind posting a sketch of this configuration?  I'm intrigued...
  • aemeeich aemeeich @ 10:48 PM
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    Buffer Tank

    I wanted the buffer tank across the closely spaced T's because if just the smallest NE bathroom zone is calling (NE corner of the house), the system loop is only moving 1gpm.  Although I have the reset curve set pretty aggressive right now, so this doesn't actually happen that often anymore.  Most of the boiler supply would flow backwards through the T's and short cycle back into the boiler. 

    Putting the buffer tank in series with the boiler loop would prevent this as well, but then I couldn't just turn off the circulator and "remove" the buffer tank from the system if I wanted to. 
    This post was edited by an admin on November 24, 2012 11:26 PM.
  • SWEI SWEI @ 12:01 AM
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    I see

    that helps - thanks!
  • Wayco Wayne Wayco Wayne @ 7:56 AM
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    with

    All due respect, I'm not seeing the benefit of running the buffer tank on a seperate circulator like that. also please explain the benefits of being able to turn it off and on. I would have used the buffer tank as a hydraulic separator in place of the close set of tees or just run it in series with the return to the boiler. I'm interested in the benefits you were planning on in your configuration.
  • aemeeich aemeeich @ 8:54 AM
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    Buffer Tank

    How would you use it as a hydraulic separator? There are 2 - 1" tappings, and 2 - 3/4" tappings. Not large enough for proper flow.

    The main reason was for maintaining reasonable flow across the close T's for both the gas boiler and the oil boiler. If I would have put the buffer tank in series with the gas boiler loop, then if I ran the oil boiler (maybe outdoor wood boiler in the future), the buffer tank wouldn't offer any benefit. Since the oil boiler has a constant firing rate of 128k BTU, it short cycles when one micro zone of 4k BTU is calling.

    Also, when the other half of the house is piped into the system, the lowest demand will be above the minimum modulation of the gas boiler so the buffer tank won't be necessary if I give up on the oil/wood boiler. Then I could use that piping/circulator for a flat plate heat exchanger used as a pre-heater for my DHW electric water heater.
  • unclejohn unclejohn @ 12:25 PM
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    What I'm doing

    The reason for my using a buffer tank is I have several small zones one is 8' of baseboard piped in 1/2". I have a solo 110 boiler. Right now the boiler is piped prim sec. I have a groundfos alph feeding my zones. I also added a smart 40 when I put the boiler in last year. I took out a oil fired which did not short cycle like my new one. I had my electric water heater tank that was only a couple of years old and my plan was to pipe the boiler return to the bottom of the 50 gal elec. tank where the bottom element was. Pipe my boiler supply to where the top element was. Pipe my system return to bottom 3/4 connection where the drain was and my system supply to the 3/4 hot water outlet. Air vent where the relief valve was and cap off the cold outlet. I have seven zones with the largest pipe size being 3/4. Anybody see a problem with that?
  • Wayco Wayne Wayco Wayne @ 6:13 PM
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    Nope

    I think that will work just fine. Connecting to the 3/4 connections may make some people nervous but there is really not much resistance since it is so short of an area that is 3/4. Just a blip from a vast resevoir to a 1 inch pipe. Just a hiccup of resistance then it's gone. If you had said you were hooking up to the cold water feed then you would have had the dip tube which is much longer and would add more resistance. But you didnt so there. As for the explanation for the buffer tank with it's own cicuit, I didnt realyze there were two heat sources. Now I think I understand. Thank you berry much.
  • Wayco Wayne Wayco Wayne @ 6:13 PM
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    Nope

    I think that will work just fine. Connecting to the 3/4 connections may make some people nervous but there is really not much resistance since it is so short of an area that is 3/4. Just a blip from a vast resevoir to a 1 inch pipe. Just a hiccup of resistance then it's gone. If you had said you were hooking up to the cold water feed then you would have had the dip tube which is much longer and would add more resistance. But you didnt so there. As for the explanation for the buffer tank with it's own cicuit, I didnt realyze there were two heat sources. Now I think I understand. Thank you berry much.
  • Wayco Wayne Wayco Wayne @ 6:13 PM
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    Nope

    I think that will work just fine. Connecting to the 3/4 connections may make some people nervous but there is really not much resistance since it is so short of an area that is 3/4. Just a blip from a vast resevoir to a 1 inch pipe. Just a hiccup of resistance then it's gone. If you had said you were hooking up to the cold water feed then you would have had the dip tube which is much longer and would add more resistance. But you didnt so there. As for the explanation for the buffer tank with it's own cicuit, I didnt realyze there were two heat sources. Now I think I understand. Thank you berry much.
  • Wayco Wayne Wayco Wayne @ 6:14 PM
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    Good gravy

    What have I done? There's 3 posts where one ought to be.
  • unclejohn unclejohn @ 8:55 AM
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    Hic cup

    Too much egg nog perhaps
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