BoilerFaultCodes.com
E133 High Lockout

Your boiler is not receiving enough gas or is struggling to light the flame needed to heat your water and radiators.

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: Gas supply error or flame failure

What causes this fault?

This fault occurs when the boiler tries to ignite three times but fails to establish or maintain a steady flame. The most common reasons are an interruption in the gas supply, a blocked pipe, or a component inside the boiler being unable to create the spark needed to light the gas.

This fault is frequently seen during extreme cold snaps, as the external condensate pipe can freeze and back up, preventing the boiler from lighting safely.

Typical repair cost £100-£350 (including labour)

DIY fix possible

Check that your gas emergency control valve is open and any prepaid gas meter has credit.Ensure other gas appliances, like a hob, are working to confirm gas supply to the property.If it is freezing outside, check if your external condensate pipe has frozen and gently thaw it with warm water.Press the Reset button for five seconds to attempt to restart the boiler.

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