An apparatus for depuration of a cooling fluid, said apparatus comprising: - cooling fluid passage ducts (12, 16) allowing the cooling fluid to enter or exit said apparatus, said cooling fluid ducts (12, 16) having distal ends (13, 17) arranged to be connected to high and low pressure connections (23, 27) of a refrigeration circuit and having proximal ends (14, 18) arranged to be connected to cooling fluid inlet/outlet fittings (32, 34) of said apparatus; - a recovery and depuration pathway of said cooling fluid; - a collection container that receives depurated cooling fluid from said recovery and depuration pathway; - a path of reintroduction of said depurated cooling fluid exiting from said collection container towards said inlet/outlet fittings (32, 34), for reintroduction of depurated cooling fluid in said refrigeration circuit, - a program means for operating the following steps by said apparatus: an automatic suction step for sucking cooling fluid from said refrigeration circuit, a step for depurating said cooling fluid and accumulation in said collection container and a step of reintroducing said depurated cooling fluid in said refrigeration circuit; characterised in that said apparatus provides a bypass pathway that connects said collection container with said distal ends (13, 17) of said passage ducts (12, 16) by a bypass fitting (95, 96), such that the flow direction of said cooling fluid drawn from said collection container enters said recovery and depuration pathway through said distal ends (13, 17), and in that said program means comprises a programmed washing means arranged to recirculate said depurated cooling fluid drawn from said collection container through said bypass pathway so that it enters said distal ends (13, 17) and passes through said passage ducts (12, 16), said recovery and depuration pathway and flows in a depurated status back into said collection container, such that the flow of depurated cooling fluid washes said distal ends (13, 17) and said passage ducts (12, 16). - cooling fluid passage ducts (12, 16) allowing the cooling fluid to enter or exit said apparatus, said cooling fluid ducts (12, 16) having distal ends (13, 17) arranged to be connected to high and low pressure connections (23, 27) of a refrigeration circuit and having proximal ends (14, 18) arranged to be connected to cooling fluid inlet/outlet fittings (32, 34) of said apparatus; - a recovery and depuration pathway of said cooling fluid; - a collection container that receives depurated cooling fluid from said recovery and depuration pathway; - a path of reintroduction of said depurated cooling fluid exiting from said collection container towards said inlet/outlet fittings (32, 34), for reintroduction of depurated cooling fluid in said refrigeration circuit, - a program means for operating the following steps by said apparatus: an automatic suction step for sucking cooling fluid from said refrigeration circuit, a step for depurating said cooling fluid and accumulation in said collection container and a step of reintroducing said depurated cooling fluid in said refrigeration circuit; said apparatus provides a bypass pathway that connects said collection container with said distal ends (13, 17) of said passage ducts (12, 16) by a bypass fitting (95, 96), such that the flow direction of said cooling fluid drawn from said collection container enters said recovery and depuration pathway through said distal ends (13, 17), and in that said program means comprises a programmed washing means arranged to recirculate said depurated cooling fluid drawn from said collection container through said bypass pathway so that it enters said distal ends (13, 17) and passes through said passage ducts (12, 16), said recovery and depuration pathway and flows in a depurated status back into said collection container, such that the flow of depurated cooling fluid washes said distal ends (13, 17) and said passage ducts (12, 16).