High
30 on Saunier Duval Ecosy

Your boiler has detected that the water inside the system is not circulating properly, causing an abnormal temperature difference between where it leaves and returns to the unit.

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

There is excessive temperature difference between the flow and return thermistors.

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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