Emergency
5 (Group 1) on Worcester Bosch Greenstar Ri

Your boiler has detected a potential safety issue with its internal gas valve or flame sensor, so it has safely locked itself out to prevent operation.

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

Ionisation detected after burner stopped, Gas valve EV2 leak test failed, Gas valve EV1 leak test failed, Ionisation current detected before burner-start, Gas valve error, Ionisation sensor shorted

Shared across the Greenstar 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 →D7View →E9View →

All 15 fault codes on the Greenstar Ri

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

1 (Group 1)2 (Group 1)3 (Group 1)4 (Group 1)6789101112131415

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