Worcester 28CDi bolier

[bacon]

Trying to re-pressurise system, we had a new filling loop fitted, when i insert the key, and open the valve i do not hear any water flowing in. The new loop has two knobs, a small black one that opens and closes, and a grey one.

How much do i turn the key and which knob to open.

 

[gasisexpensive]

take off white door on front of boiler,it lifts up and off.
pressure instructions on back of this door.
black cap could be a drain device,dont touch it !!!