Which refrigerant requires lower pressure for operation, R-22 or R-410A?

R-22, also known as HCFC-22, operates at lower pressure levels compared to R-410A. This difference in operating pressure arises from the design and intended use of these refrigerants. R-22 is a single-component refrigerant that has been widely used for many years in air conditioning and heat pump systems.

On the other hand, R-410A is a blend of two refrigerants (R-32 and R-125) and is designed to operate at higher pressures. This higher pressure not only improves the efficiency of the system but also allows for different thermal properties, making R-410A suited for newer, more efficient HVAC systems.

Given these characteristics, R-22 requires lower operating pressures, making it the correct answer. Understanding the differences in operating pressures between these refrigerants is essential for proper HVAC system design and maintenance.