We installed several KE100 thermostats in the house just before Christmas. The issue we are finding with them all is the radiators are going way above the temperature set on the thermostats, and even if the heating is on through the boiler thermostat the rad thermostats don't close to keep the radiators from heating up. 

I've calibrated. Checked the install which is correct but it is almost as if the pin isn't able to close the radiators despite being the correct setup (no bracket needed, just screw straight on).

Only got screenshot of one device but they are all the same.

Thanks in advance