Valves staying open

[wormvortex]

Recently it seems that even when the rooms separate thermostat is showing the temperature over 1degrees above the target the valve is still staying open. This didn't use to happen.

[derpuma]

Batteries? Do you use normal Alkalines? When Batteries have a heavy voltage drop under load, it is possible, that HA thinks the batteries are empty and signals don't go thru.
If you have the possibility, you can measure your Batteries voltage with a multimeter in your thermostat under load, while manually trigger a closing off the valve. Or use a decent Battery tester which tests under a load.
I had similar problems with some, even brand new, discounter batteries and switched to Lithium Ion rechargeable AAs (3600mAh) last winter. Lithium Ion's don't have a voltage drop until they are empty, like normal Alkalines have and they are much more reliable.