If the freeze sensor is connected such that it breaks the common wire connection to the solenoids, then while this will work, it allows the Iro2 to ‘think’ that it’s watering, causing moisture tracking to be badly messed up.
Instead, the freeze sensor can be connected to the Iro2’s SC and S1 terminals, along with enabling Sensor 1 for ‘rain.’ You’ll get the same (non) watering action, and, moisture tracking is correctly told that no water was put down.
This is what I’m doing now. Opening and closing the SC/S1 connection as a function of outside temperature. It’s working well.
BTW, my comments here are only for Flex Daily mode.