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Taco SR503 energizing all circulators after a zone is satisfied...

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lars49
lars49 Member Posts: 2
in Radiant Heating
My radiant floor heating has 3 zones, each with its own Taco 571 zone valve and 007-F5 circulator. I replaced the old White fan relays that controlled both with a Taco ZVC 403 zone valve controller and a Taco SR 503 switching relay for the circulators. Everything works as designed except the Taco SR 503 sends 120v to all 3 circulators for about 30 seconds after the call for heat on any zone is satisfied. So a call for heat from tstat in zone 2 causes zone 2 zone valve to open and the the end switch on the zone valve head turns on the zone 2 circulator thru the SR 503. When the tstat is satisfied, the zone 2 Valve closes but all 3 circulators kick on for 30 seconds and the shut off. Any ideas would be appreciated.

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  • Joe Mattiello
    Joe Mattiello Member Posts: 706
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    Need to know how ZVC is connected to SR503. The two controls work independently so the ZVC will energize the zone valves connected to bottom of control, and endswitch terminals 2, and 3 from the zonevalves will connect to corresponding TT terminals on SR503. Endswitch on SR503 will interface with boiler TT terminals. to troubleshoot, you may need to take all wires off, and wire one zone at a time to determine where the short is, providing you're wired as suggested. thanks
    You can contact Taco Tech support for additional information. You can always reach out to me too.
    Joe Mattiello
    N. E. Regional Manger, Commercial Products
    Taco Comfort Solutions
  • lars49
    lars49 Member Posts: 2
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    Taco Tech Support has been exceptionally helpful and solved the problem by reconstructing my configuration in their lab. Connecting the SR503 24v thermostat terminals to the end switch (terminals 2 and 3) of multiple Taco 3-wire 570 zone valves required a change in the connections between the ZVC 403 and terminals 1 and 2 of the zone valves. All zones now work individually. I’d recommend anyone call Taco Tech Support if they encounter a problem and can’t find the solution in the product literature or on-line. Greatly appreciated their help.
    Rich_LSteveSan
  • SteveSan
    SteveSan Member Posts: 234
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    Thank you Lars49 for your kind words. I know we have worked on this for a few days now. We were able to replicate your situation and find the solutions to your issue. As always Taco Tech Support is available Mon-Fri 8am-5pm EST. Taco thanks you for being a loyal customer. Have a great day.
    Rich_LHVACNUT

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