How much does it cost to fix boiler error code E9?

Typical repair cost for the boiler E9 fault is £180-320 including labour.

E9 High

Boiler Fault Code E9

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 31 August 2026

Fault code E9 appears across 5 boiler brands and 47 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 that monitors the temperature of the cooling liquid returning to the main unit has developed a fault. (As reported on Ideal HP290)

Pick your boiler brand for the E9 fix

British Gas E9 1 model Ideal E9 1 model Sime E9 2 models Viessmann E9 1 model Worcester Bosch E9 42 models

Source

Information for the E9 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 31 August 2026