High
D3 on Worcester Bosch CDi Highflow

Your boiler has stopped working because a safety link that tells the system it is safe to operate has become disconnected or faulty.

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

External temperature limiter tripped (link LR-Ls on Heatronic missing)

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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