BoilerFaultCodesTechnical description
Pump speed actual value
What causes this fault?
This code occurs when the boiler's main control board detects that the internal pump is spinning faster or slower than the speed it has been commanded to reach. It is usually caused by air bubbles trapped in the system or a build-up of debris like sludge that is physically slowing the pump's rotation. In some cases, it can also happen if the electrical signal between the pump and the main control board becomes inconsistent.
This issue is more common in autumn when heating systems are turned back on after summer, as settled debris or air pockets can migrate into the pump.
DIY fix possible
Check that all radiator valves are fully openEnsure there is enough water pressure in the system (check the gauge)Restart the boiler to see if the advisory code clears