High
45 on Alpha Evoke 10 / 18

Your boiler has sensed that the water inside is heating up far too quickly, which usually means the water isn't circulating through the system properly.

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

The boiler detects a sudden, unexpected increase in ΔT between the flow sensor and the system return sensor

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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