BoilerFaultCodes 9.1.8 High
Boiler Fault Code 9.1.8
Also written as 918 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 9.1.8 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 outdoor heat pump unit has detected a fault with a temperature sensor that monitors the air passing through it, which may cause the system to stop working correctly. (As reported on Ideal HP290)
Pick your boiler brand for the 9.1.8 fix
Source
Information for the 9.1.8 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