BoilerFaultCodesYour boiler is having trouble creating the spark or flame needed to start up because the internal ignition components are out of alignment.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Electrode settings incorrect
What causes this fault?
This fault occurs when the spark electrodes inside the boiler's burner move out of their precise position or become worn down over time. Without the correct spacing, the boiler cannot create a strong enough spark to ignite the fuel, or it may fail to detect that a flame has successfully started.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like 78 — no call-out fees, no surprises.
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Worcester Bosch Greenstar Utility 18/25 is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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