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Bypass valve?

adambuild Member Posts: 406
Happy Holidays Wallies! Quick question! I was reading the I&O manual for the new TT Prestige with Trimax control. It has a diagram for piping with zone valves and shows a bypass valve at the end. My two baseboard zones go out and back in 3/4" copper and the piping from the boiler would be 1" without primary/secondary. Will a 3/4" bypass valve be sufficient at the ends of the manifold to give the boiler enough flow?

Thanks, Adam


  • Steve Whitbeck
    Steve Whitbeck Member Posts: 669
    P/S piping

    I would suggest primary secondary piping instead of the bypass valve.

    Probably about the same cost for either but bypass valves have a bad habit of sticking open. If you are worried about water hammer on the zones then go with a delta pressure pump on the zone side.

    Just about every bypass valve I have seen in the last 10 years wasn't working.
  • adambuild
    adambuild Member Posts: 406

    Hi Steve,

    Thanks for the response. I've never used a bypass valve. I always pipe P/S. The manual however shows a bypass valve both ways, straight through and with P/S!? I guess I'll call TT tomorrow to see if it can be left out. Kindly let me know if you have any other thoughts.

    Thanks again, Adam
  • gennady
    gennady Member Posts: 835

    i think they recommending bypass valve for the purpose of setting pressure drop across radiators and as a result setting flow rate. Same as circuit setter.
  • SWEI
    SWEI Member Posts: 7,356
    edited December 2012
    use a pressure-dependent circulator

    pump direct, and don't worry about it.  If it's 110, consider replacing the internal circ with one.
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