We have two radiators in our kitchen. The battery one one was getting very low and today it announced "sensor fault" which I guess is related though the battery hadn't actually died.

When I went to change the batteries, the HR92 was showing a link error on the LCD, but was also showing a temperature set of 24.5 and was red-hot. The other radiator was still showing the correct schedule temperature.

This valve is high up out of even accidental reach. I'm a bit worried that a low battery could cause a radiator to come on full-blast, just in terms of energy use. Is this a known glitch?