High
24 on Saunier Duval Ecosy 24E

Your boiler's temperature sensors have been swapped during installation or maintenance, causing the system to become confused about which way the water is flowing.

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 flow thermistor and heating return thermistor are connected the wrong way round.

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

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