They are installed in the compressor discharge, to reduce the circulation of oil in the refrigeration circuit.
Oil related problems
Formation of foam in the oil of the compressor housing (Electrical resistance in the housing).
Removing the oil film on the compressor bearings
Reduction of the heat exchange coefficient in the evaporator and condenser
Compressor liquid blows
They are installed in the compressor discharge, to reduce the circulation of oil in the circuit.
