Whirlpool tub with automatic pre-flushing of the system

In a tub including a bottom portion having a drain opening and a fluid system connected to said tub, said fluid system having a pump including a section side and a pressure side and at least one nozzle mounted on said tub;

• said pressure side being connected to said at least one nozzle for introducing a water-and-air mixture into the interior of the tub, said fluid system further having a drain fitting connected to a circulation inflow line and a pipe drain, the improvement wherein the drain fitting comprises:
• a body adapted to be disposed beneath the bottom portion of the tub, said body including an upper chamber portion and a discharge connection portion;
• said upper chamber portion having a flow chamber, an upper opening connecting the drain opening of the tub and said flow chamber, and said discharge connection portion having a lower discharge opening connected to the drain pipe;
• a valve disk mounted on said body which is actuatable from outside said flow chamber for selectively allowing or blocking fluid communication between said upper chamber and said discharge connection portion;
• and
• said body further including first and second flow openings which are disposed in said flow chamber;
• said first and second flow openings being disposed above said valve disk, said first flow opening being connected with said inflow line and said second flow opening being connected with said suction line of said pump.