High Lockout
C.(3) on Potterton Kingfisher 2 RS60, RS80, RS100

Your boiler's small pilot light is on, but the main burner is failing to ignite, meaning your heating and hot water will not work.

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.

Technical description

Main burner fails to light, pilot burning - S.I.T. control solenoid valve failed.

What causes this fault?

This fault occurs when the gas valve receives a signal to open the main burner but fails to do so physically. The most common reason is a mechanical or electrical failure of the solenoid coil within the S.I.T. gas control valve, which prevents gas from reaching the main burner even though the pilot light is lit.

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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