Pressure washer

A pressure washer adapted to be connected to a liquid supply, said pressure washer comprising:

• a washer frame;
• a motor unit disposed on said washer frame and including a housing, an output shaft journalled on said housing, and a heat dissipation fan mounted fixedly to an end of said output shaft;
• a storage tank unit disposed on an assembly of said washer frame and said housing of said motor unit and having an outlet and a return flow port;
• a hydraulic pump unit connected operatively to an opposite end of said output shaft of said motor unit, said housing being disposed between said heat dissipation fan and said hydraulic pump unit, said hydraulic pump unit having a suction port in fluid communication with said outlet in said storage tank unit, and a discharge port in fluid communication with said return flow port in said storage tank unit, one of said storage tank unit and said suction port in said hydraulic pump unit being adapted to be connected to the liquid supply such that liquid can flow from the liquid supply into said hydraulic pump unit through said suction port, after which the liquid can flow out of said hydraulic pump unit through said discharge port;
• a spray nozzle connected to said hydraulic pump unit and in fluid communication with said discharge port in said hydraulic pump unit, said spraying nozzle being selectively openable for spraying liquid;
• and
• a check valve unit disposed between and in fluid communication with said return flow port in said storage tank unit and said discharge port in said hydraulic pump unit, said check valve unit being closed so as to prevent flow of liquid from said discharge port into said return flow port when said spray nozzle is opened, said check valve unit being opened so as to allow for the flow of liquid from said discharge port into said return flow port when said spray nozzle is closed.