Freezer switces off sporadically after periods of...

Question

Bauknecht GKEA 305 OPTIMAAfter 3 years use from new the freezer switched off and unfroze during our absence. There had been no interruption of the mains supply and the dot of light on the control panel showed that the freezer was still connected. It restarted and ran for 9 days then the indicator panel showed a flashing series of 3 lines like - - one above the other interspersed with a rapid indication of the set temperature with a 1 second cycle and loud click. The freezer was disconnected and allowed to warm to -12°C and then reconnected and started and is now behaving normally again and has reached the set temperature. It responds normally to changes in the set temperature..