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3 wire zone valves

I don't have a diagram, but I would say that if you used a relay with a set of normally open and a set of normally closed contacts (such as a Tacor sr501) you could hook the thermostat to TT, hook the common to terminal 3 hook the one that makes when it's calling to 4 no and hook the one that makes when it's satisfied to 4 nc. For the end switch, you could use the other set of contacts (5 and 6 no).

That should work with no problem, but it seems as though it would make more sense to replace the zone valve!



  • Todd_17
    Todd_17 Member Posts: 31

    Does anyone have the wiring diagram to use a 2 wire thermostat, using a relay, to power an old White Rodgers
    3 wire zone valve?
  • tim smith
    tim smith Member Posts: 2,752
    regarding wire up of zone valve

    I would change the operator head on that valve to a two wire as they don't last forever. The only quirk about this is that if you have multiple WR 3 wire zone valves the wire up can get a bit tricky. White Rodgers is notorious for a not so straight forward diagram. There web site has good documentation although but does not show the 3 wire setup w/ 2 wire stat. As other post stated, it could be easily done with a spdt relay and 2 wire stat.
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