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What am I missing?

brett288
brett288 Member Posts: 8
in Radiant Heating
A friend of mine had some guy pipe his in for hydronic system. It ran as piped for two months. I repiped it and now for some reason I can't get flow out the return manifold. I can't get the GPM gauges to hardly jump. I am wondering if the pumps have lost their ability to produce the amount of head originally intended. I will be putting a new pump in on one zone to try that. With no flow promotion I am racking my brain thinking I'm missing something. The first set of pictures are what I tore out and the second set with watts manifolds is what I put in. (the shark bite cap is for when we bring in permanent water. 

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,470
    Looks to me that you have the expansion tank & air sep on the return should be on the supply & The pumps should be pumping away. Are you pumping hot ut of the boiler through the pumps into the zones?

    Does that boiler require primary secondary piping?
  • mattmia2
    mattmia2 Member Posts: 10,924
    How much flow are you expecting vs what those can measure?
  • HVACNUT
    HVACNUT Member Posts: 6,330
    Is there a circulator in the boiler?
    No LLH?
    What does the manual say?
  • brett288
    brett288 Member Posts: 8
    mattmia2 said:
    How much flow are you expecting vs what those can measure?
    I was expecting to get around 0.5 GPM to 0.75 GPM through each loop. And they measure 0-2 GPM. 
  • brett288
    brett288 Member Posts: 8
    EBEBRATT-Ed said:
    Looks to me that you have the expansion tank & air sep on the return should be on the supply & The pumps should be pumping away. Are you pumping hot ut of the boiler through the pumps into the zones? Does that boiler require primary secondary piping?
    The pumps are pumping away from the boiler and away from the the expansion tank. The pumps are pumping into the zones. I've searched through the manual for it and it never says anything about primary secondary piping. It's a Richmond 199,900 BTU instantaneous water heater. 
  • brett288
    brett288 Member Posts: 8
    HVACNUT said:
    Is there a circulator in the boiler?
    No LLH?
    What does the manual say?
    I don't believe there's a circulator in the water heater. I'm not sure I know what you mean by LLH. 
  • brett288
    brett288 Member Posts: 8
    Here's the manual to that water heater. Like I said this is a buddy I'm just trying to help out. All this stuff was here and I'm just trying to make it work after just having him but the manifolds. 

    Manual: https://images.homedepot-static.com/catalog/pdfImages/94/94d875b5-44c8-4f5b-91a4-598f8aebf610.pdf

    Picture from the manual. It is only trying to be used for heating in floor heat. 
  • kcopp
    kcopp Member Posts: 4,472
    Its a tankless water heater...not a boiler. You are asking it to do something that it is really not supposed to do. The pressure drop through the WH AND the loops lengths are so high you are not getting flow.
    For it have any chance you need to pipe in a boiler/ primary loop and then a system/secondary loop. Then you will need to wire it to work as such.

    mattmia2
  • Jamie Hall
    Jamie Hall Member Posts: 24,842
    In addition to what @kcopp said -- which I would have said more forcefully -- that tankless has far more power than those loops can ever absorb, but since it is controlled by flow not temperature, you are going to have some serious temperature control problems in that floor.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JUGHNE
    JUGHNE Member Posts: 11,274
    If you think about this as a domestic water heater, which is all it is, it was designed to work with 40-60 PSI water pressure pushing the water thru small tubing inside it's heat exchanger.

    The pumps you have will not develop anywhere near that pressure.

    And as Jamie said, 199,000 is a lot of heat for that system to never get rid of.
  • psb75
    psb75 Member Posts: 906
    Don't walk away from this one. Run!
    Or get the proper appliance for the job.
    And install it according to the manual.
    By the way, what does the Richmond manual say about "radiant floor heating"?
  • pecmsg
    pecmsg Member Posts: 5,290
    brett288 said:

    Here's the manual to that water heater. Like I said this is a buddy I'm just trying to help out. All this stuff was here and I'm just trying to make it work after just having him but the manifolds. 

    Manual: https://images.homedepot-static.com/catalog/pdfImages/94/94d875b5-44c8-4f5b-91a4-598f8aebf610.pdf

    Picture from the manual. It is only trying to be used for heating in floor heat. 

    Page 47:
    • Inlet water temperatures above 32°F (0°C), but
    not exceeding 120°F (49°C).
    • DO NOT reverse the HOT and COLD water
    connections.
    • DO NOT connect this water heater to water lines
    previously used for space heating. All water
    piping and components shall be suitable for
    potable water
  • Mosherd1
    Mosherd1 Member Posts: 70
    edited January 2022
    @brett288 As others have said, the tankless is the wrong appliance for the job, but it can be made to work (more than likely). 1) It will have to be piped with Primary/Secondary piping. 2) the circulator on the primary will need to be a high head circulator—a Taco 0015 will probably handle it. 3) if I’m looking at the before and after pictures correctly, the three Hydrosmart circulators that you moved cannot have the shaft of the motor in the vertical position as you have them.  I currently am temporarily using a tankless for my radiant, until my house addition is done and a proper boiler is installed.

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