Patent attributes
A liquid replenishment system includes a reservoir, a first temperature sensor positioned in the reservoir at a full level, a second temperature sensor positioned in the reservoir at an add level, and a controller. The controller is connected to both the first and second sensors. The controller receives temperature signals from the first and second temperature sensors at first and second times. The controller sends an add liquid signal if temperature sensed by the first temperature sensor is substantially different at the first and second times and if temperature sensed by the second temperature sensor is substantially different at the first and second times. The controller sends a full signal if temperature sensed by the first temperature sensor is substantially the same at the first and second times and if temperature sensed by the second temperature sensor is substantially the same at the first and second times.
