The one Z-TRM3 I have that has no external sensors connected, using the internal room sensor, has for (my) practical use improved in behaviour. It’s in the hallway, normally turned off, but with the setpoint temperature high (30 C) to ensure heating starts when the unit is turned on. When I want it to heat the floor, I turn it on from a Homey flow and then off again 10-20 minutes later. I do this on the clock in the morning and afternoon, and also on the hour during the day whenever the outdoor rain sensor reports rain over the last hour. As winter and snow is coming I will have to improve the logic to also try to figure out when snow will be dragged into the hallway on shoes.
In most cases for this setup, the heating starts when the thermostat is turned on. It can be stable for several weeks, but sometimes it fails, and I have to manually adjust the temperature on the thermostat to make it work again. To me it sounds like a firmware/API problem with the Z-TRM3 itself. I might try to attach the floor sensor to see if it changes anything (and use it as an external room sensor as there is no tube to feed it under the floor).
