BoilerFaultCodesYour boiler is simply running a routine internal test to check it can operate at its maximum power level after starting up.
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: Test program where the appliance is operated in full load after successful ignition
What causes this fault?
This is not actually a fault, but a built-in safety and performance check. It occurs because the boiler needs to confirm it can safely reach its highest firing rate immediately after the burners have lit. Once the system satisfies itself that everything is venting and heating correctly at full power, the code will disappear and normal operation will resume.
DIY fix possible
Wait for the test to complete automaticallyDo not turn the boiler off while the code is displayedMonitor the display to ensure it returns to a normal temperature reading
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A boiler cover plan would cover faults like P.1 — no call-out fees, no surprises.
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