How much does it cost to fix boiler error code 600 mm?

Typical repair cost for the boiler 600 mm fault is £90-180 including labour.

600 mm High

Boiler Fault Code 600 mm

Also written as 600MM — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 7 July 2026

Fault code 600 mm 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 indicating that the flue terminal outside your home is obstructed or does not have enough clear space around it to vent safely. (As reported on Malvern TenTwenty)

Pick your boiler brand for the 600 mm fix

Malvern 600 mm 1 model

Source

Information for the 600 mm 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