What will happen if R134a is added to a system designed for R12?

When R134a is added to a system that is designed for R12, there is a significant risk of damaging critical components, specifically the compressor and seals. R12 and R134a have different chemical properties and pressures. R12 is a chlorine-based refrigerant, while R134a is a hydrofluorocarbon, which does not contain chlorine.

Adding R134a to an R12 system can result in inadequate lubrication because the oils used in R12 systems are not compatible with R134a. This mismatch can lead to increased wear and tear on the compressor, which is essential for the refrigeration cycle, and may ultimately cause it to fail prematurely. Additionally, seals that were designed to work with R12 may swell or degrade when exposed to R134a, leading to leaks and further issues in the system.

Understanding these differences highlights the potential risks involved in mixing refrigerants not designed to work together. Thus, the answer that addresses the potential damage to both the compressor and seals is correct, as it underscores the importance of maintaining the integrity of the refrigeration system by using the appropriate refrigerant.