Hello, I have firmware 2442, stability is normal, deviation within 0.5 but in PID mode partial heating of the battery is supported at -0.5°C and at +0.5°C it blocks the battery. Once again, W600 works in PID mode, it is not just open/closed.
Here is a description of the types of TVR operation, if you have time you can read it for a general understanding of the operation of W600 Understanding TRV Control Algorithms: A Comprehensive Guide