Insufficient lubrication
+
insufficient oil, oil migration
– large plant volume
à
supplement oil charge, check over longer operating time
– insufficient gas velocity, rising pipelines
à
check over longer operating time with minimum compressor
speed, change pipe runs if necessary
+
oil viscosity too low due to high dilution with refrigerant
– compressor during off cycle colder than evaporator
à
fit / check crankcase heater
– too much refrigerant
à
reduce to minimum level
– leaking solenoid valve in liquid line
à
repair / exchange
– insufficient liquid accumulation at start
à
fit "swan neck" in suction line, if required fit liquid accumulator
– too little suction gas superheat or hunting
à
superheat minimum 6..7 K, correct sensor position if
during operation
required
+
oil temperature too high
– leaking / defective working valves
à
see "safety cut-out"
– worn piston rings
à
exchange, check pistons and cylinder liners
+
oil no longer capable of lubricating
– contaminated by wear particles or foreign matter
à
check magnetic plug, oil filter and base plate,
change oil (repeatedly if required), cure cause
– chemically decomposed, increased moisture content
à
check for acid / moisture content, check for coke deposits
(valve plate) and Cu plating (sliding surfaces, valve plate).
Change oil and drier (repeatedly if required), cure cause
(renew hose connections which have increased porosity)
+
oil pump / oil regulation valve defective
à
repair / exchange
+
suction pressure at oil pump inlet too low
– oil filter blocked
à
clean, oil change, with possible wear, exchange compressor
– suction filter blocked
à
clean, cure cause
Cut-out due to oil pressure switch (if fitted) or damage to sliding surfaces and bearings
Possible reasons
Measures, recommendations
Component damage
+
Components in compressor defective
– overloading, liquid slugging
à
repair / exchange, cure cause
– lack of lubrication
à
repair / exchange, cure cause
– usual wear
à
repair / exchange
+
Magnetic clutch defective
– magnet overloaded
à
exchange, cure cause (e.g. loss of voltage due to
corroded connecting terminals)
– bearing overloaded, excessive belt tension
à
exchange, cure cause
+
Shaft seal leaking
(oil leakage up to approx. 0,05 cm
3
/h within tolerance)
– lack of lubrication
à
exchange, see "insufficient lubrication" for guide
– too much axial play of crankshaft
à
set axial play
– overheating (hardening, cracks, oil coke)
à
exchange, cure cause
– strong vibration (loose clutch, belt drive not
à
exchange, cure cause
aligned, irregular drive)
– excessive belt tension
à
adjust belt tension
Compressor does not run despite demand and drive, only heavily or with unusual noises
