How much does it cost to fix boiler error code AL 90?

Typical repair cost for the boiler AL 90 fault is £120-350 including labour.

AL 90 High

Boiler Fault Code AL 90

Also written as AL90 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code AL 90 appears across 1 boiler brand and 6 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is struggling to burn gas correctly and has shut down for safety because it cannot reach its required operating settings. (As reported on Sime Halstead Trio)

Pick your boiler brand for the AL 90 fix

Sime AL 90 6 models

Source

Information for the AL 90 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