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Taco pumps and zone valves wiring with SR503 relay


I have a hot water radiant system with 2 zones hooked to a Quietside DPW 120 heater.  The current system has 2 pumps, one for eash zone, controlled by a Taco SR503 switching relay.  I added a 3rd zone and plumbed it into one of the two existing pump zones and then added 2 Taco (EBV) zone valves.  My idea is to have the second and now third zones activate one pump and respective valves when each calls for heat.  My question is how do I wire both pumps and valves with this setup and the SR503?  I have looked online for diagrams that address this but I not found any.



  • JStar
    JStar Member Posts: 2,752

    Treat the zone valve end switches as the "thermostat" at the zone board. You can pigtail them together on one terminal for the pump. You then need a separate transformer to power the valves and thermostat circuit.
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