LB
II
-PLUS Technical Manual
41
Abnormal vibration or noise
1. Bearing damage.
2. Compressor liquid compression.
3. The rotor is overheated & friction with the rotor or the shell.
4. Oil loss causes poor lubrication.
5. The internal parts loose
6. Poor piping, without flexible stretch causing resonance
7. The foreign matter enters the compression chamber.
Discharge temperature too high
1. High overheat of suction refrigerant (insufficient refrigerant, abnormal expansion
valve).
2. High pressure too high (bad cooling, air comes into the system, high temperature of
cooling water, insufficient cooling water flow, poor heat transfer effect of condenser).
3. The compression ratio is too large, no auxiliary cooling.
4. Bearing damage, rotor friction.
5. The loss of oil or oil level is too low.
System low pressure alarm
1. Insufficient refrigerant
2. The evaporator has severe frosting, which affects heat transfer.
3. The opening of the expansion valve is too small, the temp package is loose, and the
thermal insulation is not made.
4. The suction filter is frozen or dirty.
5. The evaporator is too small.
6. Low pressure protection setting problem.
System high pressure alarm
1. Too much refrigerant
2. The effect of heat exchange is not good
3. The discharge temperature is too high.
4. The expansion valve is dirty and blocked.
5. The condenser is too small.
6. High pressure protection setting problem.
Oil flow alarm
1. Oil flow switch failure
2. The condensing pressure cannot be set up at starting, and the oil supply pressure
difference is not enough.
3. Oil circuit blocked
4. Oil circuit solenoid valve failure
Discharge temperature too low
1. Compressor suction has fluid
2. Oil return temperature too low
3. The opening of the expansion valve of the system is too large
4. The opening of the economic expansion valve is too big
Insufficient oil supply in compressor
1. Discharge temperature too low
2. Oil separator filter failure
3. Oil temperature of the oil separator is too low (not open oil heater before starting)
4. Suction or gas supplement has liquid
5. Economic expansion valve opening is too big
6. Insufficient oil returning during suction
7. Excessive pressure drop in external oil circuit, poor oil supply