BoilerFaultCodesTechnical description
Pump map (heating - combi & system only)
What causes this fault?
This fault occurs when the boiler's control board loses communication with the internal pump or cannot determine the correct flow rate for your radiators. It is usually caused by a mechanical failure within the pump itself or a glitch in the main circuit board that prevents it from sending the correct speed signals. In some cases, a build-up of debris in the system can also put too much strain on the pump, causing it to fail this internal check.
This issue often comes to light in autumn when the heating is turned on for the first time after summer, as the pump can seize up 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.