RXF ROTARY SCREW COMPRESSOR UNITS
MAINTENANCE
070.410-IOM (JAN 12)
Page 35
TROUBLESHOOTING THE COMPRESSOR
EXCESSIVE NOISE and
VIBRATION
Loose bolts on compressor mounting. Tighten bolts.
No oil getting to compressor. Check oil level, oil lter and oil pressure.
Bearing damage or excessive wear.
Coupling loose on shaft. Tighten coupling. Replace if damaged.
Volumizer not adjusted correctly. Readjust.
Refrigerant ood-back. Correct system problem.
TROUBLESHOOTING THE OIL SEPARATOR
GRADUAL OIL LOSS WITH AN
OIL LEVEL IN THE COALESCER
SECTION SIGHT GLASS
Maintaining too high an oil level. Lower level.
Refrigerant carryover or liquid injection overfeeding. Correct operation.
Contaminated oil or damaged coalescer lter elements. Replace oil charge and coalescers.
Coalescers may be loose. Tighten.
Oil return valve closed. Open return valve.
Return oil strainer blocked. Clean strainer.
RAPID LOSS WITH NO OIL
LEVEL IN THE COALESCER
SECTION SIGHT GLASS
Compressor unit suction check valve did not close on shutdown. Repair valve.
Bypass open around suction check valve. Close bypass valve.
Bypass valve opened too far. Tighten
Coalescer lter elements not seated properly. Replace oil charge and coalescers.
Oil viscosity too low. Verify correct oil, replace if incorrect.
High system CFM. System operating out of design conditions (High suction and Low discharge
pressures).
Refrigerant ood-back. Correct system problem.
Two or more compressors piped to a single economizer vapor port. Verify check valves are in
working order.
TROUBLESHOOTING THE LIQUID INJECTION OIL COOLING SYSTEM
SYMPTOM PROBABLE CAUSES and CORRECTIONS
HIGH OIL TEMPERATURE Insufcient liquid supply. Check receiver level. Check strainer.
Suction superheat too high. Correct system problem.
Liquid strainer blocked. Clean strainer.
Operating conditions signicantly different from design.
Malfunctioning Vi Control Solenoids. See function check of the compressor
"Volumizer II Vi Control" for further detail.
Check motor valve operation and calibration.
Check calibration of analog output.
LOW OIL TEMPERATURE Equalizing pressure too low. Raise pressure.
Suction superheat too low or refrigerant ood back on compressor. Correct system problem.
Operating conditions signicantly different from design.
Check motor valve operation and calibration.
Check calibration of analog output.
OIL TEMPERATURE
FLUCTUATES
System conditions rapidly uctuate causing liquid injection system to overrespond. Stabilize
system operation.
Check calibration and operation of motor valve - Adjust P & ID setpoints for analog output.
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