High Lockout
F.70 on Glow-worm Energy System

Your boiler’s control computer has lost its identity settings, meaning it no longer knows which specific model it is and has shut down as a safety precaution.

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

Invalid product code (DSN)

What causes this fault?

This fault occurs when the boiler's internal memory loses the crucial identification code that tells it how to operate safely. The most common reason is a communication failure between the main control board and the display screen, often caused by a power surge or a failing electronic component.

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

F.61View →

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