High
Flame On Before Gas Valve On on Keston Combi2 C30

Your boiler's safety sensor thinks a flame is already burning before it has even turned the gas on, causing the system to shut down for safety.

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

Flame detected before the gas valve is energized. Checks: internal boiler wiring integrity and electrode condition.

From this model's manual
Verified against the Keston Combi2 C30 installation & service 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 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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