BoilerFaultCodes 9.1.28 High
Boiler Fault Code 9.1.28
Also written as 9128 — same fault.
Reviewed by the BoilerFaultCodes Editorial Team Last reviewed
Fault code 9.1.28 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 heat pump has stopped working because a sensor detected that the internal system is getting too hot, likely due to a lack of proper airflow or low refrigerant levels. (As reported on Ideal HP290)
Pick your boiler brand for the 9.1.28 fix
Source
Information for the 9.1.28 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