FAULT DETERMINATION TEST METHOD FOR SYSTEMS INCLUDING AN ELECTRONIC EXPANSION VALVE AND ELECTRONIC CONTROLLER

In a system for refrigeration and air conditioning including a microprocessor based electronic controller and an electronic expansion valve responsive to the controller, a fault determination test method for discovering operational faults in the controller and the valve. The test method further determines whether the failure is due to the valve or the controller to minimize servicing time by providing test results applicable to a logic table which indicates the failed component and the action to be taken by the service technician.