BoilerFaultCodesTechnical description
No ionisation or ionisation failure more than 5 times during one heat demand.
What causes this fault?
This fault occurs when the boiler tries to light the gas but the internal sensors cannot detect a steady flame. The most common reason is a worn-out or dirty ionisation probe that can no longer 'see' the fire, though it can also be caused by a lack of gas reaching the burner or a faulty ignition lead.
This fault can appear more frequently during the first cold snap of autumn when old electrodes that have sat idle all summer finally fail under the strain of constant use.
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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