Moisture in oil

Dirty drier filter

Low pressure of oil

Liquid refrigerant in oil

Suction pressure rises

Discharge pressure decreases

Compressor oil level falls down

Compressor oil level increases

High oil level

Liquid refrigerant entry

Shortage of refrigerant

Air entered into system

Over charge

Under charge

High condensing pressure

Partial blocking of filter drier

Excess refrigerant

High evaporator load

Insufficient refrigerant

Condenser water pump not working