Good day all. We have an Omax 5555 and cannot reduce the cutting pressure to 20 KSI. At present we can only get the pressure down to 21.4 KSI at 644 RPM. We are running water only with a .005 sapphire jewel, a .005 dump valve jewel, and a .010 excessive overflow jewel. We have replaced all of the jewels, rebuilt the dual on/off valves and also the air actuators. We have run this set up for years and had no problems with our 3050 pump running at 20 KSI. Any ideas?