BoilerFaultCodesTechnical description
Ion base value differs from the previous value – try resetting the boiler
What causes this fault?
This fault occurs when the boiler's internal sensor detects a change in the electrical signal produced by the flame compared to its last successful start-up. The most common reason is a buildup of carbon or moisture on the sensing probe, which prevents it from reading the flame correctly. It can also be caused by a slight degradation in the ignition cable or a worn burner seal allowing air to interfere with the reading.
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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