BoilerFaultCodesTechnical description
Boiler goes to lock out | No gas, Insufficient gas, Incorrect gas valve adjustment, Electrode defective, Ignition lead defect, Electronic igniter defective
What causes this fault?
This fault occurs when the boiler attempts to ignite several times but fails to establish a flame, leading the system to shut down for safety. The most common reasons are a lack of gas reaching the unit, a worn-out spark electrode that can no longer light the burner, or a faulty gas valve failing to open. In some cases, it can be caused by something as simple as a recent gas meter exchange or the gas supply being temporarily turned off.
This fault often appears during the first cold snap of winter when components like the gas valve or ignition leads are put under sudden strain after being idle over summer.
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.