BoilerFaultCodesYour boiler's computer brain has become confused during its internal startup check and has stopped working as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Software Sequence Error
What causes this fault?
This fault occurs when the boiler's internal control board fails a self-diagnostic check during the startup phase, leading to a breakdown in communication between electronic components. The most common cause is a hardware malfunction within the main circuit board or a loose connection in the internal wiring. Because the boiler can no longer verify that it is operating safely, it enters a permanent shutdown mode to protect your home.
DIY fix possible
Locate the reset button on the control panelPress and hold the reset button for 5 secondsWait for the boiler to attempt to restart; if it fails again, contact a Gas Safe engineer
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
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