Sounds like one of two things
1: Diverter valve/motor
Does the C/H flow pipe warm up when trying to draw H/W?
Or more likely
2: Cold water inlet filter blocked or Water sensor (called a flowmeter on these boilers I believe), not sensing water movement through it.
Most work with an impellor spinning when a tap is opened, sending an electronic signal to the pcb that water is in demand, the impellor is probably not spinning, or electrically the pcb is not recieving the signal (faulty cable loom or pcb).
These type of sensors have taken over from the old type diaphragm.
Carefree, July 2010
