High
F.25 on Vaillant Combi Compact 242EB

Your boiler has shut down because it detected that the exhaust gases are getting too hot, indicating a potential internal blockage or a circulation problem.

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

Safety switch off flue gas temperature too high

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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Related fault codes

F.20View →F.22View →F.24View →

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