Just got mine VF-2 fixed, it was the pressure switch. $7.00 with shipping off of eBay. Remember that the switches can work sporadically too, if you just get an occasional alarm.
In an earlier post we joked about sitting behind the machine with a 6 pack and the spindle running slowly and watching for the pump to cycle and the pressure to go up. What I did was much easier, I just set up a video camera to watch the gauge. After an hour I watched the tape (fast forwarding) and fond that it was indeed cycling properly. Changed my switch and all was well.
Mike
Two Haas VF-2's, Haas HA5C, Haas HRT-9, Hardinge CHNC 1, Bother HS-300 Wire EDM, BobCAD V23, BobCAD V28