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primary/secondary pumping

Tim Doran
Tim Doran Member Posts: 208
It can be as simple as using the dry contacts in a multi pump relay. Are you using a reset control? Most of them can handle the primary pump. Using the boiler control is also an option but keep in mind that the primary pump may not run when the boiler is up to temp so you may get a bit of cycling.

Tim D.


  • rox
    rox Member Posts: 23
    primary/secondary pumping

    Hot water system, 4 zones, Question, how do you wire/control the circ for the primary loop in a primary/secondary system? It needs to be on any time one of the zones calls. Thanks in advance.
  • rox
    rox Member Posts: 23

    Buderus 215/3 boiler with ST150 for DHW.

    I didnt think the boiler control was a good idea for the reason stated (no primary loop circulation if boiler is above limit). Im using a Taco 4 zone control with priority (SR504) for the indirect. Wasnt planning on a reset at this time (ran out of money in the budget, figure I can add it in the future). Just not sure how to wire up a control for the primary loop circ so that it is on when any or all of the secondaries are active. Thanks.
  • Joe Mattiello
    Joe Mattiello Member Posts: 703
    Use a SR504 switching relay w/priority

    The Sr504 4 zone capacity will facilitate the wiring give you diagnostic lights, end switch that emulates the thermostat to fire the boiler when ever any zone calls for heat, and ZR terminal that will be hot with 120 when any zone calls for heat. You can use the ZR terminal for primary pump. For your convenience I attached a zone control wiring guide. Please refer to page 16 for a similar wiring diagram.

    Taco, Inc.
    Joe Mattiello
    Technical Service Technician
    [email protected]
    401-942-8000 X 484
    Joe Mattiello
    N. E. Regional Manger, Commercial Products
    Taco Comfort Solutions
  • Albany Chris
    Albany Chris Member Posts: 38
    Boiler control worked for me

    I had the exact same question, my supply house guy said to wire the primary circ to the boiler. I was sceptical, but it works. THe circ runs even when the boiler stops firing due to hitting the high temp limit.

    Boiler is a Utica MGB series
  • rox
    rox Member Posts: 23
    Thanks guys

    Thanks to all....Im certain this wont be a problem now.
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