When converting a system from R502 to R404A, what can you do with the TEV?

When converting a refrigeration system from R502 to R404A, it is generally acceptable to use the same thermal expansion valve (TEV) that was previously utilized for R502. The key reason for this is that the operating characteristics of R404A are similar to those of R502, which means that the TEV can typically manage the flow of the new refrigerant effectively.

Both refrigerants operate within similar pressure ranges and thermodynamic properties, which allows the existing TEV to function without requiring immediate replacement or modification. However, it is essential to check compatibility, as some older TEVs may not function optimally with R404A due to differences in pressure drop and other operational characteristics associated with new refrigerants.

While it is possible to reuse the TEV, maintenance of the system and performance evaluations post-implementation are critical to ensure that the system operates efficiently with the new refrigerant. Additionally, technicians often suggest assessing the condition of the TEV and ensuring it meets the desired specifications for the new refrigerant prior to reuse.