Manual Version e1-4.3.0.ae-R3. Page
5.5 Leak-Back Utility
To test the leak-back rate of each of the chambers, the Leak-back Utility can be used. This program
pumps down all chambers, and then closes all valves for a pre-set amount of time. It then estimates the
leak-back rates for each chamber and displays them. To use this utility, first choose the duration of the
test, the duration of the pumpdown before test, and then press “Start Test”. The test will be performed,
and the rates will be displayed. When the test is complete and you have observed the rates, press
“Done” to return to the Maintenance Menu. This test can be misleading for the main chamber,
however, since most apparent leaks are actually trapped gas in the showerhead. Maximum test time
and long pumpdown (60 min) time should be used for best results. The main key to distinguishing
between a leak and trapped gas is that a leak will have a steady, straight line with no sign of the
pressure rise slowing, whereas the rate of rise for trapped gas will decrease as the pressure rises. Also
see Section 6.18 for an alternative method of leak testing the main chamber.
To Next Page
Loading...