How much does it cost to fix boiler error code A0?

Typical repair cost for the boiler A0 fault is £150-250 including labour.

A0 High

Boiler Fault Code A0

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code A0 appears across 3 boiler brands and 5 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 accurately measure the temperature of the water inside its internal storage tank, which means your hot water may not heat up correctly. (As reported on Worcester Bosch Greenstar Heatslave II)

Pick your boiler brand for the A0 fix

Atag A0 2 models Viessmann A0 2 models Worcester Bosch A0 1 model

Source

Information for the A0 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