Abstract: In order to control the delivery of a liquid to a vessel, a liquid level control system includes a regulated supply of low pressure air delivered to an air supply tube which extends to a liquid vessel for discharging the low pressure air at a preselected level within the liquid vessel. The control system also includes a sensor sensing fluctuations in air pressure at an intermediate point along the air supply tube. In particular, the sensor senses a first air pressure when the liquid is below the preselected level and sensing a second, higher air pressure when the liquid is at or above the preselected level. The sensor is in communication with the liquid supply source to produce a signal upon sensing the second, higher air pressure in the air supply tube. When the higher pressure is sensed, the sensor sends the signal it produced and the liquid supply source is responsive to the signal to stop supplying liquid to the liquid vessel.