Emergency
6d on Worcester Bosch Highflow 300

Your boiler has detected that a flame is still present inside the unit even though it should have turned off, which suggests a safety control issue.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Flame detected after gas valve switched off

Shared across the range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
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 emergency 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

EAView →6AView →

All 57 fault codes on the Highflow 300

Seeing a different code? Every code this model can display, in one place.

6A6C9UA1A4A5A7A8ACAdB1b2b3b4b5b6b7C1C4C6D1d3d5d6E2E5E9EAF0F1F7FAFdH1H4H7H9HCHeatbank Overheat StatHot water high limit statNo codeoverheat lock-out statePOINT BPOINT CPOINT DPOINT EPOINT FPOINT GPOINT HPOINT IPOINT JPOINT KPOINT NS9Safety limit statSy

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