Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

2 wire to 3 wire zone valve swap

They go again under power to close in the same direction. Motor shuts off via heat-switch.


  • db_8
    db_8 Member Posts: 1
    need to know what i did wrong

    yesterday i replaced two white rodgers zone valves. having not been to the job prior to this, i was unaware that the existing valves were two wire and the ones sent to me at the jobsite were three wire. of course by this time the supply house is now closed so i installed them and wired them up just like the two wire valves, leaving i believe its the #6 terminal with no wire to it. long story short, customer called last night to say the boiler would not shut off and the tstats wouldnt do anything to close the zone valves or shut down the boiler. what did i do wrong and how do i fix it????
  • Weezbo
    Weezbo Member Posts: 6,232
    well. today is not easy to get pieces....

    so, i would likely go for going back over there put the valves open on manual lock,and providing you have a functional zone valve left on the header ...i would let it run the system until Monday. If you disconnect the wires and have no other zones and open the zones to lock open you can take leads off the TT and hook them to the two wire T stat about 10 ' from the boiler set it at 75 and tell the homeowner you will be back tomorrow and if they feel to hot or cold they can turn that thermostat up or down in the interim.
  • Empire_2
    Empire_2 Member Posts: 2,343
    Zone valves by WR

    The 2 wire is power open spring closed/ and the 3 wire is power open power close. 3 wires must go the t-stat. If not you will have to go back to the 2 wire valve. If you need help wiring the 3 wire, give a shout..

    Mike T
  • carol_3
    carol_3 Member Posts: 397

    Wow, isn't this a classic 2-wire vs 3-wire zone valve situation! They really aren't the same critter, are they? I'm for putting in 2-wire zone valves as soon as that supply house opens. Then you don't have to come up with a third wire and new 3-wire stats.
  • Empire_2
    Empire_2 Member Posts: 2,343

    I'm sorry you are correct. I think I was thinking of the HW 2 wire valve,....In this case you can go from 3 wire to 2 wire but not the other way unless you have the t-stat and additional wire from t-stat
  • Plumdog_2
    Plumdog_2 Member Posts: 873

    could have been WR 2-wire w/spring. There is such a thing.
This discussion has been closed.