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.
If our community has helped you, please consider making a contribution to support this website. Thanks!

240V heater and low voltage thermostat

Options
AmateurHour
AmateurHour Member Posts: 2
in Thermostats and Controls
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.

Thoughts?

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 26,515
    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
    EBEBRATT-Ed Member Posts: 18,828
    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
    AmateurHour Member Posts: 2
    How does this look?
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 18,828
    looks fine to me
    lbartley1959
  • utility01
    utility01 Member Posts: 1
    edited February 2022
    @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.
  • lbartley1959
    lbartley1959 Member Posts: 1
    I tried both ways and it did not work for me.
  • Jamie Hall
    Jamie Hall Member Posts: 26,515
    Did you wire it in accordance with the Aube wiring diagram?
    https://www.manualslib.com/manual/11515/Aube-Technologies-Rc840t.html
    Note that you have a choice: external thermostat or internal thermostat. NOT BOTH.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Jamie Hall
    Jamie Hall Member Posts: 26,515
    I might add -- you will need a two pole service disconnect for that heater, as the Aube relay only breaks one of the hots, not the other.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England

Categories