BoilerFaultCodesTechnical description
Electrical supply not 50Hz. Correct the electrical supply
What causes this fault?
This fault occurs when the boiler's internal computer detects that the incoming electrical current is unstable or at the wrong frequency. Common reasons include a failing motherboard that can no longer read the power supply correctly, or external interference from heavy machinery and portable generators nearby. In some cases, a fault with the street-level power grid or local electrical work can cause the supply to fluctuate enough to trigger this safety shutdown.
This fault is more common during the winter months when high demand on the national grid can lead to localized voltage drops or 'brownouts'.
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.