BoilerFaultCodes.com
304 Medium Lockout

Your boiler has been manually reset too many times in a short period and has locked itself as a safety precaution.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Too many resets have occured

What causes this fault?

This fault occurs when the reset button has been pressed more than five times within a fifteen-minute window, causing the control board to trigger a safety lockout. It is usually a secondary issue caused by a homeowner attempting to clear a recurring ignition or flame failure fault. The boiler essentially stops responding to prevent potential damage or the masking of a more serious underlying mechanical problem.

Typical repair cost £0-120 (including labour)

DIY fix possible

Turn off the power supply to the boiler at the main switch or fused spur.Wait at least 30 seconds for the internal memory to clear.Turn the power back on to clear the lockout and attempt to restart the system.

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