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240V heater and low voltage thermostat

Looking for a little confirmation from the experts on this. I have a 5000W DynaGlo heater in my garage and I'm setting it up for external thermostat control. It has a switch and terminal block for external control with a line voltage stat. I'm using an Aube RC840T-240 transformer/relay and an ecobee 3 lite stat. I've attached a sketch of what I think is how this should be wired in order to retain functionality of the internal thermostat as I believe it controls the fan delay start and cool down run.



  • Jamie Hall
    Jamie Hall Member Posts: 19,377
    Refer to the wiring diagram which is helpfully printed on the case of the RC840T-240 and the heater's diagram. You can have either the heater's thermostat active or the external one -- but not both.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 12,313
    No. You r not hooked up right.

    Connect the Blue from the RC840T-240 to L2 on the heater
    Connect the Black to #1 terminal external thermostat
    Connect the Red to #2 terminal external thermostat

    Then attach your thermostat
  • AmateurHour
    AmateurHour Member Posts: 2
    How does this look?
    EBEBRATT-Ed Member Posts: 12,313
    looks fine to me
  • utility01
    utility01 Member Posts: 1
    edited February 10
    @AmateurHour : I am doing exactly the same thing as you with a 5000W DynaGlo heater and an Aube RC840T-240 transformer/relay, but with a different thermostat.
    Did your corrected wiring diagram work out successfully?
    Thank you.