It has been just over a year since I last tried to hook up the ERV to a WiFi dimmer. But with my son’s advice and encouragement the deed was finally accomplished.
He designed a circuit for me to convert PWM (pulse width modulation, a common control for LED lighting) output to analog which the ERV requires, The LED driver that used PWM was powered only by 24 volt and I didn’t have a dimmer that worked with low voltage, although there may be one out there for outdoor lighting.
I thought the Lutron system I tried may use PWM instead of analog like the LED dimmer. The ERV requires analog 0-10 volt. But when I referred back to the documentation it said the output was analog.
Last year I purchased and tried the large GRX-TVI control box and a Lutron Caseta Pro dimmer with the Caseta bridge to make the ERV a wifi variably controlled system. I found the Lutron devices because I was looking for an analog dimmer system that controlled a motor as in the ERV. This system had an option to control a motor. In this chart the motor is an icon. The Caseta Pro is paired with the TVI to output 120v-277v with 0-10v control. The GRX-TVI and the Caseta Pro are magnetic low voltage devices.
Although after these devices didn’t control the ERV as I expected, I assumed that due to the magnetic low voltage and source and sink requirements the 0-10v output was not compatible with the ERV. I was wrong.
After the GRX-TVI experiment, I tried an Insteon dimmer switch, dimming ballast and wifi bridge, but I couldn’t even get the dimming ballast to output variable power at the 120 volt side much less the 0-10 analog side. So that was a big disappointment too. But after I got encouragement I tried again, plus this has been on my to do list for a long time.
The GRX-TVI documentation has a number of wiring diagrams that all make use of 120 power output. The wiring I tried failed to run the ERV with the outgoing signal. It could be that I had wired the GRX-TVI with the bridge wire to the switched output as shown in their documentation.
When I rethought the design I realized there was no need for the switched output. So I set it up as in this diagram.
The Caseta Pro comes with four wires and has a large range of applications but this one is quite simple. The blue wire is capped, the red wire is the dimming signal and the black is power from the distribution panel. The GRX-TVI diagram is clearly labeled for the incoming wiring. Power is black, neutral is white and the dimming signal is red.
It didn’t take long to hook up the switch and box again. And I tested the output with the dimmer switch before hooking it up to the ERV. It showed a nice variable signal on the volt meter. And lo and behold, it controls the ERV!
To use the 0-10 control on the ERV instead of the manual variable switch that comes with a unit–both cannot be used at once–I had to make a couple of jumper changes on the ERV control board. The manual switch is removed.
Next it was just a matter of updating the bridge software, it was a year old after all, and adding the switch to the wifi network. Now the ERV is controlled both by the physical switch on the wall, and the phone application.