High
UU/2 on Ariston Genus 27

Your boiler has detected that the water returning from your radiators is at an unusual temperature, which usually means the water isn't flowing through the system correctly.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Return temperature of the heating circuit (C°)

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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