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2 thermostats controlling the same circulator

Need advice. I’m re-piping a hydronic system that is being ran by a Polaris water heater so I’m using a plate type heat exchanger to separate the domestic and the hydronic piping. I have a pump on either side of the heat exchange and I have 2 zone pumps for floor heat and for an air handler. 4 pumps in total. I need the thermostats to be able to turn the 2 primary pumps on when there’s a call for heat on either zone. If i hookup the thermostats to a typical zone control then when 1 thermostat calls it would send power to the other thermostat causing both zones to run. Is there something I can install so when 1 thermostat calls it won’t send power to the thermostat that isn’t calling? Thanks for any info. 

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,495
    edited December 2023
    See the attached drawing.

    Easy to do and it should do what you need. Two relays and a transformer are probably $100 or less zone controls will cost much more and do nothing

    1 mistake on the drawing. The coil wires shown as "Blue" should be blue & white
  • Derheatmeister
    Derheatmeister Member Posts: 1,581
    A SPDT Rib relay and a transformer should work...