High Lockout
28 on Potterton Performa 28i

Your boiler has detected that the internal sensor responsible for monitoring the temperature of your heating system has developed a fault.

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

Fault on Central Heating Sensor

What causes this fault?

This fault occurs when the boiler's control board loses communication with the temperature sensor or receives an incorrect reading. The most common reason is that the sensor has physically degraded over time or the electrical wire connecting it to the main system has become loose or corroded.

This fault often appears when the heating is first turned on after summer, as the sensor may struggle to respond correctly after a long period of inactivity.

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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