High
D1 240 on Worcester Bosch Heatslave

Your boiler has lost track of the temperature of the water returning from your radiators, which usually means a internal sensor has failed or gotten wet.

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 may be wet or damaged

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

D1 241View →A7View →

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