High
12 on Ideal Response SE

Your boiler has detected that either the water pressure inside the system is too low or a safety sensor in the exhaust vent has triggered.

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

Water pressure switch or flue thermostat failure

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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