BoilerFaultCodesTechnical description
Hot water storage temperature sensor is defective – connect the plug to the hot water temperature sensor correctly, mount the hot water temperature sensor correctly or replace the hot water temperature sensor
What causes this fault?
This fault occurs when the boiler loses communication with the sensor that monitors the temperature inside your hot water cylinder. The most common reason is that the sensor has developed an internal electrical failure, or the wiring connecting the sensor to the boiler has become loose or damaged. Without this data, the boiler shuts down hot water production as a safety precaution to prevent overheating.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.