Aube On/Off Switching Electric Heating Relay with Built-in 24 V Transformer

Relay is Compatible with Low Voltage Thermostats to Improve Temperature Control and Comfort
  • Direct replacement for any brand name relay
  • Built-in 24 V transformer for easy installation
  • Compatible with 24 V thermostats with 2-wire connections (R, W) or 3-wire connections (R, W, C)
  • Immediate relay activation provides improved temperature control and comfort
  • Epoxy-soundproofed relay ensures quiet operation
  • Low current consumption means multiple relays can be controlled by a single thermostat
  • Heating command indicator light gives at-a-glance verification of relay operation
  • Terminal board connection enables easy installation

Item #: 300612T IN STOCK - SHIPS TODAY


List Price: $57.03

Your Savings: $6.53

  • Details
  • Specs
  • Reviews
  • Manuals
  • What's Included
  • The RC840T Electric Heating Relay is designed to control a line voltage resistive load from a low voltage thermostat. The RC840T relay has a built-in 24 V transformer and is compatible with 3-wire (R,C,W) thermostats as well as 2-wire mechanical and battery-operated thermostats. The RC840T operates silently and can be installed in bedrooms, living rooms, or any other occupied area without disturbing occupants. On a call for heat, the relay is immediately activated; there is no delay. This increases temperature control and comfort.

  • Specifications
    Manufacturer Aube
    Manufacturer Product No RC840T-240
    UPC 775264094620
    Voltage (VAC) 240V
    Resistive load (A) 22A
    Inductive load (HP) 1.5
    FLA 12
    LRA 42
    Control signal 24 VAC / 40 mA / 1.2 VA
    Transformer Ratings 24 VAC / 1.2 VA / Class 2
    Ambient Operating Temperature -4°F to 140°F (-20°C to 60°C)
    Ambient Storage -40°F to 175°F (-40°C to 80°C)
    Humidity Limits 0 to 95% non-condensing
    Net Weight 11.5 oz. (326 g)
    Terminal Wire Size 12 AWG
    Certification cULus

  • Reviews 1 - 10 of 44

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    Helpful to be aware of Review by Art
    Helpful to be aware of

    I successfully set up an Aube RC840T-240 so that I could control some electric baseboard heat with an ecobee4 smart thermostat. IMO, both are very good products. The setup worked very well, for awhile. When we started to use Alexa with the ecobee4 things got unstable. Whenever an Alexa command was executed, the ecobee4 would reboot repeatedly. Turns out that the transformer in the Aube is capable of only 1.2VA (power rating) and the ecobee4 requires a minimum of 3.6VA to operate reliably. Thanks to the 2015 review by Bill D. The problem was solved by purchasing a separate 24V transformer with a power rating of 20VA (call it insurance) and connecting the output to terminals RC and C on the ecobee4 while disconnecting the "c-wire" from the Aube at the t-stat and capping it off. I hope this adds to Bills excellent review and helps someone.

    Posted on 1/19/2019

    Added to my baseboard heater Review by Wendell
    Added to my baseboard heater

    Added this to the side of my electric baseboard heater to control it with a 24 volt thermostat.

    Posted on 11/17/2017

    Do not believe sales claims! Review by bill d
    Do not believe sales claims!

    I am giving the 840T a poor review because of Smarthome's sales claims. The transformer in the 840T is capable of only powering itself and "dumb" thermostats (basically switch closure thermostats) it will NOT safely power a modern digital/LCD display thermostat and definitely NOT power a WiFi thermostat. This information is directly from the manufacturer who I called today after purchasing two of these from SmartHome several months ago. Also, you cannot connect multiple relays as advertised without correctly "phasing" the line and also running the risk of the transformer in one backfeeding 240V into the other if the circuit breaker for one is turned off. This is a significant safety issue. This unit is not being advertised correctly. If you don't believe me, call Aube and they will tell you the same thing. Now I have to add a transformer and open up a wall to fish transformer wiring! Very unhappy with how this produce is represented.

    Posted on 9/28/2015

    Review of 300612T Review by NEIL
    Review of 300612T

    Good - installed with a Honeywell WiFi thermostat. Basic operational test only.

    Posted on 6/29/2014

    Review of 300612T Review by MICHAEL
    Review of 300612T

    Easy to use, self documented, works fine. Would be nice to see it's solid-state alternative offered side-by-side.

    Posted on 6/8/2014

    Review of 300612T Review by DAVID
    Review of 300612T

    fit well, seems robust construction, good price.

    Posted on 4/16/2014

    Review of 300612T Review by Rolleston Electric
    Review of 300612T

    If you are using this for more than the 22 amps you must use a contactor and just use the nest to power the contactor and let the contactor handle the load. I have done this a few times. A 10,000 watt load will burn these units up because it's 42 amps close to twice what they can handle.

    Posted on 4/2/2014

    Review of 300612T Review by BRENT
    Review of 300612T

    Very happy with my purchase. They worked as I planned.

    Posted on 3/7/2014

    Review of 300612T Review by JOACHIM
    Review of 300612T

    works perfectly with my Nest Thermostat installed in Germany.

    Posted on 3/6/2014

    Review of 300612T Review by CINDY
    Review of 300612T

    Oh,my gosh, thankyou so much for the quick delivery. this relay is exactly what we needed. now we know where to order from for other needs. Keep up the good work!!!!A 5 star rating for sure!!!!!!!!!!!!!!!!!!!!

    Posted on 2/28/2014

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    • 1x - On/Off Switching Electric Heating Relay
    • 1x - Built-in 24 V transformer

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