High Lockout
E317 on Baxi 600 Combi (range)

Your boiler has detected an issue with the electrical power supply coming into your home, meaning the electrical frequency is not compatible with the boiler's electronics.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Wrong power supply electrical frequency (Hz).

What causes this fault?

This fault occurs when the electrical current entering your boiler fluctuates outside the standard UK frequency of 50Hz, causing the boiler to shut down for safety. The most common reasons for this are a flickering local power grid, the use of a low-quality portable generator during a power cut, or a malfunctioning Printed Circuit Board that can no longer read the incoming signal correctly.

This fault is more common during periods of severe stormy weather, as lightning strikes or falling debris can cause instability and surges in the local electrical grid.

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.

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