In the forward movement  the recoil of the water pressure is used to move the cleaning nozzle against the direction of the flow up to the target shaft resp. end point. Upon arrival of the nozzle at the end point the nozzle is slowly pulled back in the direction of the flow at the drain hose.

The escaping water jets increase the flow rate of the wastewater, loosen the deposits, twirl them around and transport them as suspension to the starting shaft where they are sucked up by vacuum through a hose.