High
E11 on Keston C36p

Your boiler's internal computer is struggling to confirm the temperature difference between the water leaving and returning to the unit, causing it 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

The automatic test for calibration of flow and return sensors has failed. Check both flow and return sensors are located on the correct pipes and are producing the correct readings.

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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Related fault codes

E10View →

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