High
D1 on Worcester Bosch Greenstar CDi Compact

Your boiler has detected a faulty reading from a temperature sensor, which is preventing it from heating your water properly.

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

Return sensor error - Sensor wet or damaged (the boiler will block for 300 secs before this condition).

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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