Compressor Loading - Unloading Intervals too short
a) Erratic water thermostat
a) Replace
b) Insufficient water flow
b) Adjust gpm.
Little or no oil pressure
a) Clogged suction oil strainer
a) Clean
b) Excessive liquid in crankcase
b) Check crankcase heater. Reset expansion valve for
higher superheat. Check liquid line solenoid valve
operation
c) Oil pressure gauge defective
c) Repair or replace. Keep valve closed except when
taking readings
d) Low-oil pressure safety switch defective
d) Replace
e) Worn oil pump
e) Replace
f) Oil pump reversing gear stuck in wrong
position
f) Reverse direction of compressor rotation
g) Worn bearings
g) Replace compressor
h) Low oil level
h) Add oil
i) Loose fitting on oil lines
i) Check and tighten system
j) Pump housing gasket leaks
j) Replace gasket
k) Flooding of refrigerant into crankcase
k) Adjust thermal expansion valve
Compressor loses oil
a) Lack of refrigerant
a) Check for leaks and repair. Add refrigerant
b) Velocity in risers too low*
b) Check riser sizes
c) Oil trapped in line*
c) Check pitch of lines and refrigerant velocities
d) Excessive compression ring blow-by
d) Replace compressor
