BoilerFaultCodesTechnical description
Flow-/Return-sensor check is running, demand (DHW or heating) is blocked
What causes this fault?
This fault occurs when the boiler performs a safety check and notices that the temperature sensors for the water going out and coming back are giving conflicting or illogical readings. The most common reason is that one of the sensors has developed a fault or is starting to wear out, preventing the boiler from accurately monitoring its own performance. It pauses the heating process to ensure it doesn't overheat or run inefficiently based on incorrect data.
DIY fix possible
Wait for 15-30 minutes to see if the status clears automatically after the self-test finishesSwitch the boiler off at the fused spur switch, wait 30 seconds, and switch it back onPress the 'Reset' button (indicated by a flame with a line through it) for five seconds