High
27 on Alpha Intec 40GS2

Your boiler is struggling to circulate water properly, causing the system to overheat almost instantly, which means it has shut down to protect itself from damage.

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

Insufficient primary flow - Rapid temperature rise of primary 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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