BoilerFaultCodesTechnical description
Incorrectpumpdetected: Unsuitablepumpconnected,PWMplugnotpluggedinorhascome loose,multipleplugonthePCBnotpluggedincorrectly,interruptionin cableharness,electronicsdefective
What causes this fault?
This fault occurs when the boiler's brain loses communication with the internal pump that pushes hot water around your radiators. It is usually caused by a loose electrical connection, a damaged wiring harness, or the pump itself failing to send the correct signal back to the control board. Without this two-way communication, the boiler shuts down as a safety precaution to prevent overheating.
This fault is more common in autumn when heating systems are turned on for the first time after summer, as pump components can seize or electrical contacts can fail during long periods of inactivity.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.