Diagnostic system and method for a cooling system

A diagnostic system for a cooling system including a compressor, evaporator and condenser in fluid communication, the diagnostic system comprising:

• a controller associated with a regulator valve and producing a control signal for adjusting a valve position of said regulator valve as a function of demand for cooling;
• an ambient temperature sensor associated with the cooling system and operable to provide an ambient temperature measurement to said controller;
• an evaporator coil inlet temperature sensor associated with the cooling system and operable to provide coil inlet temperature measurement to said controller;
• an evaporator coil exit temperature sensor associated with the cooling system and operable to provide a coil exit temperature measurement to said controller;
• a diagnostic module coupled to said controller for monitoring and comparing a valve position and at least one of said ambient temperature measurement, coil inlet temperature measurement and coil exit temperature measurement with at least one predetermined fault value indicative of a fault condition.