How do I drop the front cover to adjust the pump flow on a Greenstar CDi?

I have dropped the front cover giving access to the control panel, but cannot see any screws at all. All rads are heating o k, but i am getting a rushing noise from some rads, and occassionally hissing.
I thought if I could turn the pump down this may help, but from your answer this appears not to be the case anyway

Brian
December 2010

Casing comes off via 2 screws on the top and 2 on the side (1 either side of the panel which houses the thermostats), but the pump is a fully-modulating type and the boiler's electronics dictate its speed.

What is your aim? Are certain rads not being heated?

CMac
December 2010