Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Parallel primary loop?

subcooler
subcooler Member Posts: 140

Comments

  • Timco
    Timco Member Posts: 3,040


    I have a conv gravity system I am replacing, and it has three zones out from the boiler room. Since all zones are the same heat demand, would a parallel primary system using crossover bridges be better suited? With the primary loop @ 5gpm, how is the balancing valve (flow rate) figured for the crossover bridge?

    Thanks, Tim
    Just a guy running some pipes.
  • Timco
    Timco Member Posts: 3,040


    Is there not much benifit to using this piping method vs. regular p/s?

    Tim
    Just a guy running some pipes.
  • siggy
    siggy Member Posts: 79
    parallel primary loops

    Tim,

    My opinion on parallel primary loops has changed in the last couple of years. You can achieve the same benefits (equal supply water temperature and hydraulic separation) with a hydraulic separator, and eliminate the need for a primary circulator. Sample drawing attached. See the Hydronics Workshop column in the upcoming November issue of PM for more details.

    Siggy
  • S Ebels
    S Ebels Member Posts: 2,322
    Siggy

    Isn't the boiler circ in your drawing in effect becoming the "primary circ"? So really you're making the circ serve a dual purpose?

    PS: I agree on the LLH/hydraulic sep concept. Much easier and less piping than two pipe pri/sec. Wonder where that idea came from?
  • mp1969
    mp1969 Member Posts: 226


    Whose brand of hydraulic seperator do you recommend??? A very new concept to me. But I am willing to learn.

    MP1969
  • Ted_9
    Ted_9 Member Posts: 1,718
  • Timco
    Timco Member Posts: 3,040


    This is a very new concept to me as well...was going to just go p/s, but thought the parallel primary loop looked like a interesting option. When one CI boiler is used, and all 3 zones want equal heat, is there a need to go p/s or would 2-pipe direct return w/ boiler bypass be the ticket? Am planning on seperate circs for the zones, not zv's. Piping is a small loop, not large enough to need reverse return.

    Thanks a million,

    Tim
    Just a guy running some pipes.
This discussion has been closed.