Turn the leakage selector valve to LOWRANGE. No leakage should be indicated on thelow-range rotameter. Return the leakage-selectorvalve to HIGH RANGE and the inlet pressureon/off valve to the ON position.Slowly open the low-pressure regulator untilthe regulated low-pressure gage indicates 160 psig.(The N2 input pressure gage should read its gageguard pressure of 145 ± 5 psig). Turn the inletpressure on/off valve to OFF. No leakage shouldbe indicated on the high-range leakage rotameter.Turn the leakage selector valve to the LOW-RANGE position. No leakage should be indicatedon the low-range leakage rotameter. Use thesystem bleed valve to decrease the pressure to 70psig. You must turn the low-pressure regulatorcounterclockwise until 70 psig is maintained.Leave the test stand in this condition; it is set upfor you to perform your next leakage test.ROTAMETER SYSTEMThe purpose of the rotameter system is todetermine leakage or to make adjustments toitems that require bleed adjustments, such as the20004 miniature regulator. The system consists oftwo in-system rotameters and one overloadrotameter as shown in figure 2-6. The source ofpressure for the in-system rotameters is thelow-pressure regulator (N). You receive yoursource of pressure for the overboard rotameterfrom the item under test.PRESSURIZING THEROTAMETER SYSTEMSTo use the rotameter system, turn the inletpressure on/off valve (L) to ON.NOTE: Before you pressurize the rotametersystems, be sure the leakage selector valve (F) isin the HIGH position. This valve should alwaysbe in the HIGH position unless you are using thelow-range rotameter to read low readings.Turn the leakage on/off valve (G) to ON andthe inlet pressure on/off valve to OFF. Look atyour high-range leakage rotameter. If no leakageis indicated, turn your leakage selector valve (F)to the LOW RANGE position. Check yourlow-range leakage rotameter for leaks. In bothleakage tests if the small ball rises in theFigure 2-6.—Model 1172AS100 rotameter system.2-7
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