WAREWASH MACHINE WITH SOIL DETECTION AND METHOD OF DETECTING SOILING IN SUCH A WAREWASH MACHINE

摘要

A warewash machine includes a tank for holding liquid to be sprayed on items in a spray chamber and a recirculation line for delivering liquid from the tank to nozzles for spraying. A sensor arrangement is provided for monitoring condition of tank liquid, the sensor arrangement including an light emitter and a light receiver. A control is provided for energizing the light emitter and monitoring output of the light receiver, wherein the control is configured to vary the energization level of the light emitter during sensing to extend a useful range of measurement the sensor arrangement. The sensor arrangement may be located in line with or in parallel with a drain line of the tank.