BoilerFaultCodesYour boiler has entered a temporary lock-out mode because a service engineer's diagnostic tool was recently plugged in and has not been properly disconnected or reset.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Diagnosis tool was connected and is now locked out
What causes this fault?
This fault occurs when the boiler's internal computer remains in 'diagnostic mode' after being connected to a technician's service tool. It signifies that the communication between the boiler and the external hardware was interrupted or not closed down correctly, causing the system to stay frozen for safety. In most cases, it is simply a digital hang-up rather than a component failure.
DIY fix possible
Locate the reset button on the boiler control panel.Press and hold the reset button for 5 seconds.Wait for the boiler to complete its startup sequence; if the code persists, a technician may need to re-insert and properly exit their diagnostic software.
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A boiler cover plan would cover faults like 226 — no call-out fees, no surprises.
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