Spirirt Z-Wave Plus thermostat not reaching set temperature

I’m new to the whole home automation thing so maybe I’m making a simple mistake somewhere… I don’t think it’s really an openhab issue but maybe hardware…
I have a spirit z-wave plus thermostat and I’m using it with external temperature sensor.

I have my temperature set to 22C. External sensor is sending 20C. Spirit is showing current temperature as 20.5C and the valve at 0%. It’s completely closed, so no heating, the room will never reach 22C.

If I either send external temperature 15C or set target temperature to 28C then the valve will open 100%.

My question is, why isn’t it heating up the room to set 22C?

It sounds like the valve direction needs to be inverted. I’d guess that the thermostat things it needs to turn the valve to 0% to heat and 100% to turn off the heat. But I’m just guessing. I’ve no experience with this sort of configuration.

Often there is a parameters on the Thing you can send to the device to invert the direction like this.

I don’t think that’s it. When the valve is at 100% it’s fully open.

I might have solved it, though. I was sending external temperature to it with 3 decimal places (so for ex. 20.245 C). I now round it up to just 1 decimal place (so 20.2). I’ve also messed with other settings, reset the whole thing etc., so I’m not 100% sure what helped. It seems it started working correctly. At least for now.