High
40 50 70 on Chaffoteaux Serelia 24 MFFI

Your boiler is struggling to accurately detect the temperature of the water being sent to your hot water tank, causing the system to stop heating it properly.

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

Thermistor cylinder bypassed

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

40 60 70View →

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