High Lockout
E28 on Potterton Gold Combi HE

Your boiler has detected a problem with the sensor that monitors the temperature of the exhaust gases, causing the system to shut down for safety.

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 NTC sensor fault

What causes this fault?

This fault occurs when the internal safety sensor detects that the exhaust gases are either too hot or the sensor itself has developed an electrical failure. The most common reason is a build-up of debris or heat damage within the sensor, preventing it from sending a reliable signal to the main control board.

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.

Find a Gas Safe engineer
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Related fault codes

E20View →E50View →

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