High
40 50 80 on Chaffoteaux Serelia 24 MFFI

Your boiler has lost the ability to measure the temperature of the water being stored for your taps, which prevents it from heating your hot water correctly.

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 open

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 80View →

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