High Lockout
RED LED LIGHT on Vokera Option

Your boiler has stopped working because it failed to light the flame properly, or there is an internal communication error preventing it from running.

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

Fault condition - check NTC sensor or control board connections.

What causes this fault?

This fault occurs when the boiler's internal computer can no longer accurately read the temperature of the water flowing through the system. The most common reason is that a temperature sensor has failed or become disconnected, though it can also be caused by the main control board failing to process the signal correctly.

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.

Find a Gas Safe engineer
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