Subcooling on systems that use a thermostatic expansion valve (TXV) should be approximately 10F to 18F. Higher subcooling indicates excess refrigerant backing up in the condenser. For example, 275 psi head pressure on an R-22 system converts to 124F. The liquid line temperature is 88F.Click to see full answer. Besides, what are the normal operating pressures for r22? Example R-22 Refrigerant Temperature vs Pressure Data Ambient Temperature in °F1 R22 Vapor Pressure at Sea Level R-22 Low Side Pressure2 95°F (35°C) 181.9 psig 68 psi 110°F (43.3°C) 226.4 psig 150°F (65.6°C) 381.7 psig Secondly, where can I take subcooling readings? Measure the liquid line temperature of the device. The liquid line is the pipe that carries the refrigerant from the unit’s condensing coil to the expansion valve. To measure the temperature, strap the thermometer’s probe on the liquid line approximately six inches from the expansion valve and record the results. Considering this, what is the proper subcooling? Generally speaking 10° – 12° of subcooling at the outlet of the condenser coil is most common but you must look for the proper design subcooling for the particular system you are working on. Some systems will require subcooling readings of up to 16° for maximum efficiency and capacity.What should the high and low side pressures be for r22?Summary: it is Environmental Protection Agency (EPA) illegal to mix coolant types in a heating, ventilation and air conditioning (HVAC) system. In my (2) R22-based HVAC systems, the low pressure side is 40 and 45 degrees Fahrenheit (F) while the high side is 110 and 115 degrees.