High
F.70 on Glow-worm Energy Regular

The boiler's internal computer has lost its identification settings, usually because a new control board was fitted without being programmed correctly for your specific 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.

What the manual says

Manufacturer manual

Invalid product code (DSN). Display and PCB replaced at same time and Device Specific Number not reset, wrong or missing output range coding resistance

From this model's manual
Verified against the Glow Worm Energy Regular installation & service manual, page 30.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

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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