BoilerFaultCodesTechnical description
No 230V at sL to N; check external controls and mains supply.
What causes this fault?
This fault occurs when the boiler is powered on but isn't receiving the necessary electrical 'command' from your external controls to start heating. The most common reason is a failure in the communication line between your room thermostat, programmer, or motorized valves and the boiler itself. Essentially, the boiler is waiting for a green light to fire up that never arrives because of a fault in those external components.
This issue is frequently discovered during the first cold snap of autumn when homeowners switch their heating back on after months of inactivity, causing stuck motorized valves to fail.
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.