ESCO Air Conditioning Practice Exam 2025 - Free AC Certification Practice Questions and Study Guide

To find the approximate pressure of R-134a as it leaves the condenser, we first need to understand the phase change that the refrigerant undergoes in the condenser. The refrigerant enters the condenser as a saturated vapor at 124 psiG and 100°F. During this process, the refrigerant will lose heat and condense into a liquid state.

When the refrigerant has been subcooled by 20°F, it means that the temperature of the liquid refrigerant is now 20°F less than the saturation temperature at the given pressure, indicating that it is below its saturation temperature. To find the subcooled liquid’s pressure, we can refer to the pressure-temperature relationship specific to R-134a.

At 124 psiG, the saturation temperature of R-134a is approximately 100°F. When the refrigerant is subcooled by 20°F, its new temperature is around 80°F. Looking at the pressure-temperature chart for R-134a, at 80°F, the corresponding saturation pressure is significantly lower than 124 psiG. The subcooled liquid will be at a pressure that is somewhat higher than the saturation pressure at that specific temperature.

Given that the subcooling occurs, the pressure