High
E19 on Saunier Duval Thelia 23E

Your boiler has lost its connection to the heat sensor, so it has effectively stopped working because it cannot accurately measure the water temperature.

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

Central heating thermistor (NTC) disconnected

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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