BoilerFaultCodesYour boiler has detected that the electrical supply coming into the unit is currently too high, which could cause damage to internal parts if left unchecked.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Supply voltage is above high limit, your boiler should continue to operate but you need to Contact a heating engineer
What causes this fault?
This fault occurs when the electrical current entering the boiler exceeds the safe operating limits required by the internal electronics. The most common reason is a power surge or a fluctuation in the local grid supply, though it can also be caused by a failing Printed Circuit Board (PCB) that is no longer able to regulate incoming voltage correctly.
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 U2-01 — no call-out fees, no surprises.
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