How much does it cost to fix boiler error code AL 40?

Typical repair cost for the boiler AL 40 fault is £100-350 including labour.

AL 40 High

Boiler Fault Code AL 40

Also written as AL40 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code AL 40 appears across 1 boiler brand and 14 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has detected an issue with the electrical power supply coming into your home, meaning the frequency of the electricity does not match what the boiler needs to operate safely. (As reported on Sime Brava One HE)

Pick your boiler brand for the AL 40 fix

Sime AL 40 14 models

Source

Information for the AL 40 fault code is sourced from the official service / installation manual for each model that displays it. Read more about how we source fault codes →

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026