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isolating 2 zone control valves from the T-T connections on a new boiler

Just installed a new Weil-McLain CGa-5 boiler. Using two (ancient, but working with previous boiler) White-Rodgers zone valves - 24 vac. There are two red, one white, wires coming off them to attach to the boiler. I caught the repeated warning in the boiler instructions to NOT attach the 3 wire valves directly to the T-T leads. It stated I must have an "isolation relay" between the two. When I search to buy one, I am faced with telling them exactly what kind of relay I need. Can you help me to know exactly which kind to ask for? Voltage... DO/DC... or something different? My knowledge is obviously limited.
Thank you for any reply; without heat right now!


  • STEVEusaPA
    STEVEusaPA Member Posts: 5,292
    Just a RIB, found at any supply house
  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,303
    RIBU1C, it will accept the 24vac you have running the valves. Post back when you have it, and get some pics of the valves.
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!