High
F25 on Vaillant ecoMAX Pro 18E

Your boiler has detected that the water temperature is rising far too quickly, so it has shut down to prevent potential overheating.

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

Maximum temperature rise slope

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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