A cleaning robot that includes a housing having a front portion, a rear portion, a door and a hinge; wherein the door is pivotally connected to the rear portion of the housing via the hinge; wherein the rear portion comprises a rear opening; wherein the door is arranged to move between a closed position in which the door substantially closes the rear opening and an open position in which the door does not close the rear opening; wherein the door comprises a floating element or is coupled to a floating element, wherein the floating element is positioned and shaped to induce the door to move to the closed position when the cleaning robot is submerged in fluid and to remain in an open position when out of a pool and positioned in a horizontal position.