Your boiler has detected that hot water is being called for, but it believes the pump is running when it shouldn't be or there is a circulation issue preventing proper operation.

DHW demand – error pump running

What causes this fault?

This fault occurs when the boiler detects a conflict in the heating water flow while trying to provide hot water. It usually means the internal pump is stuck in the ‘on’ position or a sensor is sending incorrect signals to the main control board about water movement. This prevents the boiler from safely managing the temperature, leading to a shutdown to protect internal components.