I recently had a Generac Synergy generator installed, which went smoothly, however there was no good way to get the Y wire from my thermostat to the transfer switch and back in order to allow the transfer switch to cut the y wire signal.

It seems like this should be able to be done wireless as 24v DC is available in both the transfer switch and at the thermostat with some kind of a wireless relay, but I have had trouble identifying a suitable product, so I'm not sure if there may be some problem with my thought process.

Is there a good way to have a wireless transmitter in my transfer switch which can wireless cause a 24v relay to cut power on the y line either at my thermostat or at my AC unit? If not, what are the problems such a system would encounter that prevent it from being reliable.

  • Load shed. The Synergy is a variable speed whole house unit. If load rapidly increases, it cuts high loads temporarily (5 minutes) and spins the generator up to full power. There is a relay in the transfer switch specifically for this purpose, I just need to wirelessly connect to it. Mar 18 '15 at 16:14
  • Could you not just put your AC on one of these relays so instead of cutting the control wiring for the AC, it cuts the electrical supply?
    – Steven
    Mar 18 '15 at 20:04
  • It's a 24 volt connector that can break the 24vac circuit not a120v relay and it is a whole house switch outside. That said I'm now considering splicing in outside and simply running the 24vac line around the outside of the house. Mar 18 '15 at 20:05
  • IF it were simpler than running a new line, you could use their 24V relay to drive a line-voltage relay to disconnect your AC (240v I'd imagine).
    – Steven
    Mar 18 '15 at 20:27
  • That would be harder as I'd need to run the 240 circuit from inside to out and then back in or run a control line to a box inside to cut power (which Generac actually has a solution for, but requires some extra hardware) Mar 18 '15 at 20:32

While such a thing as a wireless relay exists, it's mighty expensive compared to the simpler option, which'd be to run thermostat wire over to the transfer switch to carry the Y and switched-Y wires there, and use the existing relay contacts on the transfer switch control board.

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