Has anyone every had any issues with the inlet isolation valve on IDP series scroll pumps either sticking, opening and then closing during initial startup, or not fully opening. My IDP 7 is not achieving anywhere close to specified ultimate pressure and has recently had its tip seals replaced. It is also pumping in stages during initial start up where the pressure decreases by 100mbar then stops for a like 10 sec, there is also a sound when this happens similar to a solenoid valve in motion. Any ideas or help, the pump has about 11000 hrs on it.