Hello! I am looking to set up a smart control arrangement for my Energy Recovery Ventilator. I am looking to monitor energy usage, turn the ERV on an off (put it in standby mode), and set it to boost (run at a higher flow rate) based on air quality monitors that I'll connect through Home Assistant. Since I am looking to achieve three main control functions, I am looking at installing three Shelly devices.
The Panasonic ERV I have is the FV-15ESC1 and it includes dry contacts that put the unit into standby and boost.
I was looking at the Shelly EM Mini Gen4 for Power Monitoring and two Shelly 1 Gen4s to control the dry contact functions on the ERV. Here is the install guide: 15ESC1450_english_ final editable. I also pasted a picture of the dry contact wiring diagram from the guide and the PCB diagram from the guide.
To keep everything essentially in the same junction box and to avoid transformers, I was going to bring a 120V AC circuit into the junction box and power all of the Shelly devices via that circuit. Then power the ERV from that circuit as well.
I dont know if there is a strong advantage to using a power source other than the 120V AC powering the ERV.
My understanding of from looking into the NEC is I can keep the dry contact wiring in the same junction box as the line voltage wiring as long as I use wiring with insulation that's rated for line voltage. I was going to use 14ga THHN for everything anyway.
Can anyone let me know if you see any glaring issues with my plan? Or if there is a simpler way to achieve my goals?
Here's My Proposed Wiring Diagram
