How much does it cost to fix boiler error code UU/1?

Typical repair cost for the boiler UU/1 fault is £90-180 including labour.

UU/1 High

Boiler Fault Code UU/1

Also written as UU1 — same fault.

Reviewed by the BoilerFaultCodes Editorial Team Last reviewed 27 April 2026

Fault code UU/1 appears across 1 boiler brand and 3 models. The exact meaning varies by manufacturer — pick your boiler brand below to see the model-specific fix.

Most common meaning Your boiler has detected that the water leaving the unit to heat your radiators is at an incorrect temperature, which usually indicates an issue with the sensor or water flow. (As reported on Ariston Genus Premium)

Pick your boiler brand for the UU/1 fix

Ariston UU/1 3 models

Source

Information for the UU/1 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