BoilerFaultCodesYour boiler has detected an internal electrical error that is preventing it from running safely, and it usually means the main control board is confused or failing.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Printed circuit board (PCB) lockout
What causes this fault?
This fault occurs when the boiler's internal computer becomes confused or fails to monitor its own electronic signals correctly. The most common reason is a failing printed circuit board (PCB) that can no longer communicate with the boiler's components, often triggered by power surges or aging electrical components. In some cases, external electrical interference from a faulty pump or loose wiring can also cause the system to shut down for safety.
DIY fix possible
Turn the boiler off at the main electrical switchWait 30 seconds before switching it back onPress and hold the 'Reset' button for five seconds
Find a Gas Safe engineer
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A boiler cover plan would cover faults like E168 — no call-out fees, no surprises.
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Potterton Promax is discontinued — time for a new one?
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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