How to add Sepang refrigeration oil to air conditioner?

Of course, the compressor should also be lubricated, because it is also a piston-connecting rod mechanism, just like the engine, but much smaller. (The air pump used for home decoration also needs the corresponding grade of lubricating oil for lubrication. ) Refrigerant must be added first. It's winter now, just add refrigerant first. Because the pressure in the air conditioning system is very high, the pressure in the refrigerant tank can't be added if you want.