Emerson VSSG, VSG manual 3. Troubleshooting Guide - General Problems & Solutions 2 of

Section 6 • Troubleshooting

Table 6-3. Troubleshooting Guide - General Problems & Solutions (2 of 3)

Problem

Solution

	• Oil return line from coalescing side of oil separator to suction is closed, not
		open enough (.75 turns should be sufficient), or plugged with debris
	• The check valve in the oil return line could be stuck closed or the flow 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
Oil Loss Issues		contamination)
	• The operating conditions are not correct (too high of suction and/or too low
		discharge pressure) This creates increased gas flow 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
	• 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.
High oil temperature (liquid	•	Check the oil cooler and associated piping to make sure it is full of oil before
injection)		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.
	• Calibration method not correct
	• Actuator or Gear motor not working, or off on overload
	• Slide valve carriage assembly out of position, slides binding
Capacity/Volume Slide	• Cross-shaft gears, broken pins
Actuator Alarms/Trips/
	•	Command shaft broken
Symptoms:
	• Slide valve rack or rack shaft damaged
	• Check balance piston movement
	• Reference Slide Valve Actuator Troubleshooting Guide
	•	Check I/O fusing

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