BoilerFaultCodesYour boiler has detected an electrical wiring error where the power supply wires are crossed or incorrectly connected.
Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now — this fault can be dangerous if ignored.
Technical description: Wiring fault Live on neutral connection
What causes this fault?
This fault occurs when the electrical supply to the boiler has been wired incorrectly, meaning the live and neutral connections are reversed. It usually happens after recent electrical work near the boiler or if an external component like a pump or programmer has been replaced incorrectly. The boiler's safety system detects this mismatch and shuts down to prevent electrical damage or a safety hazard.
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.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like n — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Potterton Envoy 30 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.
Affiliate links — we may earn a commission at no extra cost to you.