BoilerFaultCodesYour 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.
Book a Gas Safe engineer within 24–48 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 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 E317 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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