How much does it cost to fix boiler error code 4-A5?

Typical repair cost for the boiler 4-A5 fault is £80-120 including labour.

4-A5 Low

Boiler Fault Code 4-A5

Also written as 4A5 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 4-A5 appears across 1 boiler brand and 1 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler is simply letting you know that it has reached its scheduled running time and is now due for a routine service. (As reported on Worcester Bosch Greenstar 2000)

Pick your boiler brand for the 4-A5 fix

Worcester Bosch 4-A5 1 model

Source

Information for the 4-A5 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 27 April 2026