High
E33 on Ferroli Maxima 35 S

Your boiler has detected a communication error with its flue venting system, which means it will stop working to ensure your home remains safe.

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

Flue sensor fault (short/open circuit)

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

E32View →E34View →

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