Using the P-T Chart to Diagnose Refrigeration, A/C System Problems
Manufacturers of refrigerants, controls, and other suppliers distribute hundreds of thousands of pressure-temperature charts to the trade every year. It would be rare indeed to find service technicians who could not put their hands on a pressure-temperature (P-T) card at a minute’s notice.
In spite of the widespread availability and apparent reference to the pressure-temperature relationship, very few service technicians seem to use the P-T chart properly in diagnosing service problems.