High
Er 09 on Biasi Advance 25C

Your boiler has detected that a sensor monitoring the temperature of the exhaust gases is not working correctly, causing the system to shut down for safety.

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

Faulty flue temperature probe NTC

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

Er 01View →Er 02View →Er 05View →

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