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can you use thermostatic control valves with a diverter system?

Greetings from Beautiful Grand Isle, Vermont.  My wife and I are building a camp.  I have talked her into making it bigger,  It now is a small 3 bedroom house, 32x22, walk out livable basement floor with 2 bedrooms, bath, small living room.  That floor will be heated with fin tube.  Main floor with kitchen, dining room, bath, small living room.  That floor will be heated with old cast iron radiators. Top floor, 24x20, single room, very small 1/2 bath, That floor will have cast iron radiators.  The boiler is a hang on the wall Trinity propane with domestic hot water built in.

I don't know much about hot water heat.  A friend who moonlights on the side of his regular job at a heating ventilating contractor Is doing the plumbing. He wants to use a single pipe with diverter  T's for the radiarors.  Can a thermostatic valve then be used for each radiator?  Thanks,  Bob Pomykala


  • croydoncorgi
    croydoncorgi Member Posts: 83

    Depending on the Ts you use, you might need to use 'high-lift' thermostatic valves to get enough flow into the radiators....

    Also makes a big difference how you pipe-up the radiators: ie. ideally, with the inlet pipe at the top, outlet at the bottom, opposite end.
  • will smith_4
    will smith_4 Member Posts: 259
    Don't see why not

    When you think about it, monoflows just create a restriction in the roadway to induce flow where it might not ordinarily go. If you put in a thermostatic valve which reduces flow to this equation, water will just go where it sees even less path of resistance, and just bypass the zone which is closed off.
  • kcopp
    kcopp Member Posts: 4,444
    You can BUT...

    you will need a diverter valve that will open up if that TRV is closed. You see these on European Panel Rad.... You would be better off to do as I have w/ my house to home run each rad to a common manifold w/ say 1/2" pex this will give you more control w/o all the presure drop.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
    You can BUTT...

    and there's a BUTT in every crowd, ain't there?

    Choking off the side branch of a one pipe fitting creates a LOT of resistance to flow.

    As Kev said, so long as you have a bypass type of TRV, it will work, but I think your better off piping it in a parallel reverse return manner. Then when a valve closes, the pressure drop of the loop will not increase significantly, and flow will actually be diverted to the radiators that are not yet satisfied.

    Then, you can use one of the variable speed, constant pressure pumps and make it that much more efficient.

    Definitely go with a modulating condensing boiler.


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