High Lockout
B(2) on Potterton Flamingo RS40 RS50

Your boiler's pilot light is likely going out because a safety sensor has lost its connection, preventing the unit from staying lit.

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

Loose thermocouple connection into control valve

What causes this fault?

This fault occurs when the safety sensor that detects the pilot light fails to send a clear signal back to the main gas valve. The most common reason is that the physical connection between the thermocouple and the control box has vibrated loose or become corroded over time. Because the boiler can no longer verify that a flame is present, it shuts off the gas supply as a safety precaution.

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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Related fault codes

B(1)View →

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