High
1 9 on Saunier Duval Ecosy 24E

Your boiler has shut down because it thinks the water returning to the system is dangerously hot, which could indicate a flow blockage or a faulty sensor.

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

The heating return thermistor is detecting an excessive temperature.

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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