Once a technician gets comfortable with taking superheat and subcooling measurements, that technician will never again even think about diagnosing a system without that important data. Knowing superheat and subcooling of a system is like being able to see inside of the system. For example; if your superheat on a fixed metering system is in line but your subcooling is high but your head pressure is not out of line, there is a restriction in the condensing side of the system that needs to be taken care of. Once you are used to taking superheat and subcooling measurements and you understand what those numbers tell you about the operation of the refrigerant system, your eyes will be opened to a whole new dimension of troubleshooting.