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Powering a circulating pump

paulson
paulson Member Posts: 1
in Radiant Heating
Installed the radiant heat system in my garage with one continuously operating circulator pump, and one zone pump controlled by a thermostat. When it is not real cold, the circulating pump alone gets the garage too warm without the zone pump coming on. So I wired them both to come on when the thermostat calls for heat. That works great, but now I would like to add a second zone pump With its own thermostat. My problem is, I would like the circulating pump to come on when either thermostat is calling for heat. That would have two sources of AC power going to the circulating pump, and I’m not sure that’s OK? If both zones call for heat at the same time, the circulating pump will receive two sources of AC power. Not sure what to do.

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 24,884
    It's not OK. However, it's easy enough to do this with a couple of relays. Each thermostat energizes its own zone pump. It also energizes its own relay. The normally open dry contacts of the two relays are wired in parallel in the power feed to the circulating pump. Then when either thermostat calls, one of the relays will close and power the pump.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Ironman
    Ironman Member Posts: 7,556
    From your description, I'm not exactly sure what you have or what you're trying to accomplish.

    What's the heat source? Why do you have one pump operating continuously and one controlled by a thermostat?

    Can you post some pics or a diagram? We may be able to show you a better approach.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    Zman
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    Sounds like you need a Taco 2 (or more) zone relay.
    Wire each zone circ and thermostat to it's proper zone. And wire the other circ as a system circulator on the boiler's aquastat. Bring x-x from the zone control to the t-t (or x-x) on the aquastat.
    When either zone calls, that zone plus system circ will run.

    There was an error rendering this rich post.

  • SteveSan
    SteveSan Member Posts: 263
    It sounds like you are asking for a primary pump to come on when either zones calls. If you purchase a Taco SR502-4 and wire the primary pump as shown in the diagram you will not need to control it with another t-stat. That primary pump will come on when one of the other two zone calls. The hot leg will wire to the ZR and you can pick up the N at any N on the board. Any questions please feel free to call into Taco Tech Support 401-942-8000 Mon-Fri 8am-5pm EST.
    Erin Holohan Haskell

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