Venmar (Vanee/Broan) ERV / HVAC controller output

Unfortunately I have the touch controller so will have to look into if that had proper locations to connect to ESP32. Also wondering if it would be simpler to connect the ESP32 directly to ERV control terminals for auxiliary control either directly or using a relay.

Hello guys, nice thread! been peepin at it for a while now. I have the touchscreen control and I wish I could change the working mode to recirculation/turbo/continuous as well as speeds at will with my own controller. I’m currently sniffing out the comms with an RS485 USB dongle. Baud rate seems to be 38400 and boy there is a lot going on. ERV pings controller every few miliseconds until controller answers. Then they share data continuously one after the other. Next step will be to emulate the controller from my PC… wish me luck! I’m begining to find the switchbot idea pretty elegant…

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Good luck, I have the touch controller as well. Another approach with that one maybe to see if you can emulate the secondary Bluetooth controller for it. It won’t provide full control but at least you can have it set to turbo for 20/40/60 minute intervals with that function.

Good luck!

I got me two RS485 dongles, I was going to do a RPi Man-in-the-Middle attack on it where at first it just forwards traffic, then later can insert traffic.

Then my job got seriously busy and that had to be postponed.

I’m running the Switchbot now, but it does get out of sync every now and then, so I’m really hoping you’ll be successful!