BoilerFaultCodes H00 266 High
Boiler Fault Code H00 266
Also written as H00266 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code H00 266 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 experiencing a communication error with its internal water pressure sensor, which prevents it from safely operating your heating or hot water. (As reported on Potterton Promax 15 & 24)
Pick your boiler brand for the H00 266 fix
Source
Information for the H00 266 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