BoilerFaultCodes 6-t3 Medium
Boiler Fault Code 6-t3
Also written as 6T3 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 6-t3 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 staying on and circulating water continuously because it thinks it is in a permanent cooling-down phase, even when it isn't needed. (As reported on Worcester Bosch Greenstar 2000)
Pick your boiler brand for the 6-t3 fix
Source
Information for the 6-t3 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