BoilerFaultCodesYour boiler is currently running its own internal health check as it starts up and may just need a moment to finish.
This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.
Technical description: Part of the self-test sequence sequence when switching on the appliance
What causes this fault?
This occurs when the boiler is performing a routine electronic check of its internal components immediately after being powered on. It is a programmed safety sequence designed to ensure all sensors and controls are responding correctly before the burner ignites. Most often, the code will clear itself within seconds once the software confirms the system is safe to operate.
This code may be seen more frequently following a power cut, which are more common during stormy winter weather.
DIY fix possible
Wait up to 30 seconds for the self-test to completePress the reset button if the code stays on the screen for more than a minuteTurn the power switch off and back on again once
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A boiler cover plan would cover faults like P4 — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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