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System or boiler bypass ?

Thanks for your insight . Most of our installs are with baseboard or convector zones that don't hold enough water to require a bypass . But it's good to know we're using the right method when we need it .


  • How do you choose which piping method ?

    We replaced a one zone oil boiler the other day . It was in a basement of a strip mall , right next to a steam boiler . We had no idea which store it served , or what kind of heat emitters it was connected to . It did have a bypass . We piped in a new bypass - we teed it in on the discharge side of the circ right into the return . I forget what type of bypass this is called . But we were wondering how to choose the best method for bypassing . The way we did it pumps hot water right back into the boiler , which is easy to pipe for one zone , but more complicated for multiple zones . Would that be the deciding factor ? How many zones are being connected ?
  • clammy
    clammy Member Posts: 3,089
    system by pass

    Ron that type of set up is called a system by pass ,to me it is my perferred way to pipe a oil fired boiler espically to a large water content system or if cold return temps will be occuring .It works great if you also a have tankless coil and a 8124 triple aquastat it helps reduce cycling of the pump on low limit and lets your zones heat a little slower because the temp rise on the system supply and return aren't so wide depending on how much your by passing .It does get a little tougher on multi pump systems but at that point you should probalby look at a thermostatic valve for the return if it seems like a problem .I,ve used by passes on smaller residental jobs using a single pump and zone valves and just a small 1/2 system by pass with a globe valve to throttle the by pass it also cut down on velocity noises when one single zone calls . peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
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