i have a worcester greenstar 30si boiler the pressure was low?

you have to turn the key approx a half turn clockwise then turn the square capstan head adjacent to the key to allow water into the system.
As water enters the system, you'll see the pressure gauge reading slowly increase. When the pressure has reached around 1.5 bar shut off the water by turning the square capstan head until water stops flowing into the system (you can usually hear when the water flow has stopped).

Next turn the key approx a half turn anticlockwise to seal the system. When you remove the key you may get a little water dripping out. If water still continues to flow out, you haven't sealed the system, insert the key and turn anticlockwise again.

EM
April 2010