BoilerFaultCodes.com
12-65 High Lockout

Your boiler is having trouble starting the burner safely and needs a simple restart to clear a temporary electronic glitch.

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: Ignition scott actuators error – try resetting the boiler

What causes this fault?

This fault occurs when the boiler's internal computer is unable to correctly calibrate the movement of the gas valve during the startup sequence. The most common reason is a temporary communication lag between the control board and the ignition components, though it can also indicate that the components are beginning to wear out.

Typical repair cost £100-£250 (including labour)

DIY fix possible

Locate the Reset button on the boiler control panelPress and hold the Reset button for 5 secondsWait for the boiler to complete its startup sequence

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Protect yourself from future repair bills

A boiler cover plan would cover faults like 12-65 — no call-out fees, no surprises.

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