High Lockout
0E45 on Alpha Pro Tec Plus

Your boiler has detected an issue with the sensor that monitors the temperature of the gases leaving your system, which is preventing it from firing up safely.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Flue sensor short circuit.

What causes this fault?

This fault occurs when the sensor responsible for measuring the temperature of the exhaust gases sends an incorrect electrical signal to the boiler's brain. The most common reason is that the sensor has suffered an internal electrical failure or the connecting wires have become damaged or loose. Because the boiler can no longer safely monitor heat levels in the flue, it shuts down immediately 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.

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