Diagnostic system for detecting faulty sensors in a refrigeration system

摘要

When sensors are employed to monitor different operating variables or parameters in a refrigeration system, the sensor outputs will normally have predetermined known relationships with respect to each other as long as the sensors are functioning properly and regardless of the operating condition of the refrigeration system. By comparing the output of one sensor relative to that of another sensor, a faulty condition of either of those two sensors may be detected. For example, during stabilized system operation the output of a condenser pressure sensor should always indicate a higher pressure than that reflected by the output of an evaporator pressure sensor. By effectively subtracting the evaporator pressure from the condenser pressure, a faulty sensor may be discovered. If the result of the subtraction is zero or negative, at least one of the pressure sensors is defective. When a faulty sensor is detected, a warning message is displayed to operating personnel.