I recently set up a millivolt switched gas heater with an Ecobee3 thermostat. I used an RIBU1C relay to accomplish this (Ecobee wants to switch a 24VAC circuit, and the gas heater wants a millivolt circuit switch). That all works great. (I followed this guide.)

Now I have the bright idea of turning on a 110v fan every time the heater turns on, to better distribute heat from the heater. I'm looking at the 110V leads on the RIBU1C and it seems like I could just wire that up like a 110V light switch inline to the hot wire on the fan?

Basically this is how I think the system would work

I would appreciate advice on whether I am misunderstanding how the 110V lines on the RIBU1C work (maybe they are for 110V signal input and not designed to switch on/off 110V lines?)

I have decent/safe household 110V electrical knowledge (I can safely install light switches, direct wired overhead fans, etc), and a smattering of electronics knowledge. So I'm comfortable making the 110V wiring from the wall to the fan safe. I just want some external input to make sure I don't let the magic smoke out of my relay, or the Ecobee, or otherwise do something dumb.


Your proposed use of that relay looks fine.

The key item in the relay specifications is "1/3 HP @ 120-240 Vac (N/O)." That says that a normally open relay contact of that relay is rated for controlling a 1/3 horsepower motor powered from a voltage from 120 to 240 volts. 1/3 Hp is about 250 watts mechanical output of the motor. Your fan does not likely exceed that power level.

  • \$\begingroup\$ It turns out that written on the box are instructions that the the 24VAC and 110VAC switches are not to be used at the same time. So I'll need to add a second switch to the circuit to activate a fan. I'm just adding this to be sure someone else doesn't try to put a load on both switches at the same time: the box says not to do that. \$\endgroup\$ Jun 3 at 15:46

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