BoilerFaultCodesTechnical description
Communication error - variable speed internal pump. Control mode, max. pump speed
What causes this fault?
This fault occurs when the boiler's main brain loses its connection with the internal pump that pushes hot water around your radiators. The most common reason is a mechanical failure within the pump itself, though it can also be caused by loose or damaged wiring that prevents the control board from sending signals to the pump.
This fault often appears at the start of autumn when the heating is turned on after a long summer break, as pumps can seize if they haven't moved for several months.
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.
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