Emerson Vilter VSS User Manual

6 – 6
VSS/VSM/VSH/VSSH • Installation, Operation and Maintenance Manual • Emerson • 35391SD
Section 6 • Troubleshooting
Problem Solution
Low Oil Pressure at Start
• After failing to start compressor with “Prelube Oil Pump Inhibit”, rst
allow Discharge pressure, Oil Filter In pressure and Out pressure to equalize.
Then restart compressor. If compressor fails to start due to low oil pressure,
continue troubleshooting with items below.
• Reset Prelube Oil Pressure Setpoint in Alarms and Trip Setpoints
screen to lowest recommended setpoints.
• Check calibration of oil manifold transducer, discharge pressure trans-
ducer, and suction transducer.
• Check for correct oil pump motor rotation and operation.
• Ensure transducer isolation valves are open.
• Verify that the correct transducer ranges are selected.
• Check to see all oil line valves are open except the oil dump valve used
to ll the lines and oil cooler.
• Check oil strainer for dirt.
• Check oil lter pressure drop.
• Check “Prelube Oil Pressure Safety Changeover” setpoint is sufcient
in Timers Screen.
• Prelube Oil Pressure is Manifold Pressure minus Discharge Pressure.
Low Run Oil Pressure
• Check solutions in “Low Oil Pressure at Start”.
• Check that there is proper discharge pressure ratio to create differ-
ential pressure, otherwise oil pressure can’t be maintained. Oil pressure is
manifold oil pressure minus the suction pressure. It is a net pressure.
Oil ow or oil pressure
problems
• Clean oil strainer screen.
• Change oil lter, maybe plugged or collapsed.
• Oil pump gears worn internally, excessive end-clearance.
• Oil priming valve used on air-cooled cooler units is open.
• Relief in-line check valve stuck open.
• Pressure ratio too low, oil pump should be on.
Faulty pressure or tempera-
ture readings
• Check that the correct pressure or temperature range is selected in
the Instrument Calibration menu.
• Check cable connections at device, terminal strips, and PLC input card
for correct wiring and shielding (RF noise).
• Check calibration of RTDs and transducers.
Table 6-3. Troubleshooting Guide - General Problems & Solutions (1 of 3)

Emerson Vilter VSS Specifications

General

Brand	Emerson
Model	Vilter VSS
Category	Air Compressor
Language	English