BoilerFaultCodesYour boiler has stopped working because it has been reset too many times while trying to clear a burner fault, and it has now locked itself for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: More than five attempts at a reset during Burner lockout fault 9F 855, no more reset attempts can be made.
What causes this fault?
This fault occurs when the boiler's safety system permanently locks itself to prevent damage after the manual reset button has been pressed too many times. It is triggered by an underlying failure in the burner system, such as a blocked oil nozzle or a faulty ignition component, which prevents the flame from lighting correctly. Once this specific code appears, the boiler will no longer respond to simple resets and requires a professional intervention to clear the memory.
This fault is frequently seen in autumn and winter when the oil in the tank or supply lines becomes more viscous due to the cold, potentially leading to blockages that trigger the initial burner failure.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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