6 – 6
VSG/VSSG • Installation, Operation and Maintenance Manual •Vilter/Emerson • 35391STG
Section 6 • Troubleshooting
Problem
Solution
Oil Loss Issues
• Oil return line from coalescing side of oil separator to suction is closed, not
open enough (.75 turns should be suf
fi
cient), or plugged with debris
• The check valve in the oil return line could be stuck closed or the
fl
ow is in the
wrong direction
• There may be water in the oil affecting the coalescing elements
• Coalescent elements in need of replacement due to age or damage (water
contamination)
• The operating conditions are not correct (too high of suction and/or too low
discharge pressure) This creates increased gas
fl
ow which could make the oil
separator too small
• The suction or discharge check valve is not working correctly causing oil to
escape when the unit stops
• Viscosity of oil incorrect; send sample for testing
• There is an oil leak somewhere in the system
High oil temperature (liquid
injection)
• Check for correct setting of all manual values.
• Check for correct operation of 2-way automatic oil mixing valve.
• In the “Vilter Only” menu, ensure that you select “Yes this unit has the oil
mixing valve” to enable it.
• If your are controlling a step type oil cooler or a VFD oil cooler, verify the
correct one is selected in the “Vilter Only” menu and the amount of steps are
entered in the menu screen “Oil Cooler Step Control” menu.
• Check the oil cooler and associated piping to make sure it is full of oil before
starting.
• Check the oil strainer for debris and clean if necessary.
• Verify that the volume slide actuator is functioning correctly and that the
correct compressor size (type) is selected in the “Vilter Only” menu.
• Check that all fans are working.
• Check for correct fan rotation on the oil cooler.
• Check that your operating conditions are within the “As Sold” design
conditions.
Capacity/Volume Slide
Actuator Alarms/Trips/
Symptoms:
• Calibration method not correct
• Actuator or Gear motor not working, or off on overload
• Slide valve carriage assembly out of position, slides binding
• Cross-shaft gears, broken pins
• Command shaft broken
• Slide valve rack or rack shaft damaged
• Check balance piston movement
• Reference Slide Valve Actuator Troubleshooting Guide
• Check I/O fusing
Table 6-3. Troubleshooting Guide - General Problems & Solutions (2 of 3)