Technical description
Flow temperature sensor short-circuit
What causes this fault?
This fault occurs when the electrical signal from the sensor that monitors the outgoing water temperature is interrupted, usually due to a physical failure inside the component. The most common reason is that moisture or heat stress over time has damaged the sensor's internal wiring, causing it to send an incorrect 'short-circuit' signal to the main control board. If the sensor cannot safely report the temperature, the boiler will shut down as a safety precaution.
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.