High
d.33 on Glow-worm Flexicom 24c / 28c

Your boiler's air extraction system is not reaching the necessary speed to safely clear waste gases, so the unit has stopped working to prevent a safety hazard.

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

Fan speed target value

From this model's manual
Verified against the Glow Worm Flexicom 24c 28c installation & service manual, page 44.
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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