BoilerFaultCodes.com
11-66 High

Your boiler is struggling to light or recognize that a flame has started, causing it to shut down for safety after several failed attempts.

Technical description: Flame Signal loss in safety time – try to reset the boiler after 3rd unsuccessful ignition
Typical repair cost: £120-350 (including labour)

DIY fix possible

Check if other gas appliances, like a hob, are working to ensure gas is reaching the propertyCheck that your gas meter is in credit if you use a prepay meterLocate the reset button on the control panel and press it once to attempt a restart

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Protect yourself from future repair bills

A boiler cover plan would cover faults like 11-66 — no call-out fees, no surprises.

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