I'm a current customer. I'd like to leverage the existing app and wireless functionality of the thermostat to act as a switch and provide me with remote control-ability of an electric hot water heater. I would not use the thermostat functionality of the tstat unit, but would use wireless to control when the HWH is on or off. I plan to use a relay and transformer to step down the voltage from (120/2240v) to 12/24v. Has anyone used this in a similar application? Open to suggestions or concerns.
Some have done similar things. So If I understand you correctly the step down transformer would be used as an on/off switch for the power to the Hot water tank. If that is the case you would like the ability to turn it on and off. So off the step down transformer you would have 2 wires I would attach them to the fan wires (G and RC) and use the fan on and off to control it if you don’t need programing capability. If you do need programing capability then I would attach to Cool (RH and Y) So in the program when you want it off set the temp to 90 and when you want it to run set the temp to 40.
You will also need to power the thermostat with 24 v – you can us a separate transformer for this put one wire on RH and the other on C — Note some step down transformers have a C wire option built in.
If you have any additional questions please don’t hesitate to contact us.
Your Radio Thermostat Support Team