A manual switch has a body, a button, a valve rod and a biasing member. The body has a valve mount having multiple holding ribs. The valve rod is mounted slidably in the valve mount, is pressed by the button and has a valve rod, a mounting tube and an O-ring. The rod body has an outer diameter smaller than the inner diameter of the valve mount. The mounting tube is mounted securely around the rod body and has an outer diameter being equal to the inner diameter of the valve mount and an outer surface abutting with the holding ribs in the valve mount. The O-ring is mounted around the rod body and abuts with the inner surface of the valve mount to provide a sealing effect to the valve rod and the valve mount.
