BoilerFaultCodesTechnical description
Burner blocked - Internal error (Check ionisation electrode and leads/flue gas system)
What causes this fault?
This fault occurs when the boiler's internal sensors fail to confirm that a steady flame has been established, causing the system to shut down for safety. The most common reason is a worn or carbon-coated detection probe that can no longer 'see' the flame, though it can also be caused by a blockage in the air supply or chimney preventing clean combustion.
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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