With the heating off turn on the hot tap, does 'd' appear in the display, if no, the HW thermistor is at fault.
If yes, put your hand on the CH flow pipe whilst tap is running, does it get hot? If so, diverter/actuator fault
Carefree
December 2010
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.