The ExactCharge Diagnostic Assistant Application was designed to aid qualified and certified refrigeration service technicians in determining refrigerant state malfunctions occurring in a system. REGARDING THE REVIEWS: I am an HVAC/R technician with over 22 years in the field. It was and is not my intent to replace a qualified service technician with this program. I could make it output a possible failure based on input of information but prefer that the repair decision making be left in the hands of the technician. What do you want for $2.99? It to fix the system for you? This software includes diagnostic REFERENCES for fixed metering devices as well as txv metering devices. It is able to refer the technician to a LIKELY component failure or condition that could be effecting the systems operation. By referencing the Pressure/Temperature and Superheat/Subcooling readings of the system with the Diagnostic Assistant Software the service technician is BETTER able to identify possible refrigerant state malfunctions occurring in the unit. Readouts include diagnostics for blocked coils,liquid restrictions,refrigerant overcharges,and others. This software is not designed to take the place of a qualified technician only to aid one in their diagnostic tests of the systems operatiion and refrigerant state conditions.