How much does it cost to fix boiler error code 30-80 (M, M, L, L, M, M)?

Typical repair cost for the boiler 30-80 (M, M, L, L, M, M) fault is £120-200 including labour.

30-80 (M, M, L, L, M, M) High

Boiler Fault Code 30-80 (M, M, L, L, M, M)

Also written as 3080MMLLMM — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code 30-80 (M, M, L, L, M, M) appears across 1 boiler brand and 2 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 that the water temperature sensor is not providing a valid reading, causing the system to stop working as a safety precaution. (As reported on Chaffoteaux Serelia 24 MFFI)

Pick your boiler brand for the 30-80 (M, M, L, L, M, M) fix

Chaffoteaux 30-80 (M, M, L, L, M, M) 2 models

Source

Information for the 30-80 (M, M, L, L, M, M) 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