1. Oil should not contain moisture, a dust, metal particles etc.
2. Do not mix some oil of various types.
3. Moisture content in oil increases, if it remains open on air a long time. After oil use the capacity with oil is necessary for closing immediately tightly.
At replacement of elements of system be convinced that added only a certain volume of oil.
Volume of the oil added at replacement:
Evaporator: 30 cm
Condenser: 40 cm
Dryer / receiver: 20 cm
Compressor: 50 cm
Tubes: 10 cm3