Your boiler is struggling to switch between providing heating and hot water, meaning you likely have no hot water available.

Diverter valve does not operate (DHW test) / 230V at pin 3 of terminal X7 (Brown wire)

What causes this fault?

This fault occurs when the boiler's internal brain tries to switch the water flow from your radiators to your hot taps but receives no response from the switching mechanism. The most common reason is that the small electric motor responsible for moving the valve has burnt out or the internal valve itself has become seized due to a buildup of debris and sludge within the system.