BoilerFaultCodes.com
F.65 High Lockout

Your boiler’s internal computer has overheated, causing it to shut down to prevent permanent damage.

Call an engineer soon

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

Technical description: Electronics temperature too high | Electronics too hot due to external effect, electronics defective

What causes this fault?

This fault occurs when the boiler's internal control center, the PCB, reaches an unsafe operating temperature. It is usually caused by heat radiation from a leaking internal component or a hardware failure within the electronics themselves that causes them to self-overheat. The boiler shuts down immediately to protect the delicate circuitry from melting or catching fire.

This fault is more common during the peak of summer, as high ambient temperatures in a kitchen cupboard or loft space make it much harder for the boiler's electronics to stay cool.

Typical repair cost £280-550 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Protect yourself from future repair bills

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