New boiler installed but now I think pump is bad. Tried to pull a shot and all I got was a dribble. Attached gauge to portafilter and only achieved about 2.7bar (40psi). Pump is filling boiler okay but doesn't seem to be able to generate enough pressure at group. Tried adjusting pump pressure using adjustment screw on pump but no change. Verified no blockages in all plumbing and valves in group and all was clear. Do I now need a new pump?