Wire existing fan controller with relay in series


(Marc Kurtz) #1

I have two fans connected on a single switch to an existing dimmer fan controller that I would like to control with SmartThings. Since it’s two fans, they pull somewhere around 3 amps which is higher than any zwave/zigbee fan controllers on the market (prove me wrong!). So my idea is to keep my existing dimmer fan controller and wire a relay in series to turn it on/off.

As I understand it, I should be able to wire the relay in series “behind” the fan controller. So if I understand this correctly I would take the line from the box and connect it to the line on the relay and then connect the load of the relay to the line on the fan controller and then finally connect the line of the fan controller to the fan. Both the fan controller and the relay neutrals all get wired to a common neutral in the box. This would allow me to turn the fan on/off via SmartThings, but I would have to get up off the couch and go to the physical switch to change the fan speed. I would also need to have the physical switch “on” for it to turn on when I turned on the relay via SmartThings.

  1. Will this work?

  2. Some of these relays have a “switch” loop. I assume this is for wiring in “parallel” where the physical switch controls the relay. Is it correct that I can’t use that since in the end that’s only an on/off signal and not a for “dimmer” which my fan controller is.

  3. Is there any other solution? Did I get everything right?


(Marc Kurtz) #2

Anyone? Mostly I want to confirm that wiring the relay in series like I laid out will work the way I think it will.


(Ray) #3

I think it’s easier to install the GE Z-wave fan switch https://www.amazon.com/gp/aw/d/B00PYMGVVQ/ref=mp_s_a_1_1?ie=UTF8&qid=1491508120&sr=8-1-spons&pi=AC_SX236_SY340_FMwebp_QL65&keywords=z-wave+fan+control&psc=1#featureBulletsAndDetailBullets_secondary_view_div_1491508155497

The series circuit described above should work but not very smart so if you have neutral, line and load wires at the switch box. I would highly recommend the GE switch.
Some people even installed the GE fan switch at the fan fixture box with a GE addon switch at the switch box location. I don’t recommend this way but it’s something to look into for local electrical code.


(Marc Kurtz) #4

Thanks, but the GE fan controller is only 1.5 amps like all the other zwave fan controllers. So that won’t work for my multi-fan setup.


(Ray) #5

It’s 1000 Watts. So should be around 8 amps.


(Don) #6

Wasn’t me, but I read where one of the members has 2 fans on his GE controller. Obviously depends on fans, but I would think 1000 watts 8 amps is alot of room for 2 ceiling fans.


(Ray) #7

OK my fault again. Looked up the spec and it’s 1.5 amp for Fan.