R-407C as an R-22 Retrofit - Step-by-Step Guide

R-407C is a mature HFC blend (R-32/R-125/R-134a) commonly used as a drop-in style replacement for R-22 in residential AC, heat pumps, and chillers. It's not the only option, but it's widely available, well-understood, and non-flammable.

When R-407C is the right choice

• →Existing R-22 system that's 8–15 years old (worth extending, not replacing yet)
• →Budget-constrained retrofit (compressor stays, some components swap)
• →A1 non-flammable classification needed for the installation space

Step-by-step retrofit

• →1. Recover R-22 to a recovery cylinder. Send for reclaim.
• →2. Change oil from mineral (R-22 original) to POE - flush or drain procedure
• →3. Replace the filter drier
• →4. Replace or adjust the expansion device - TXV often needs a new power head sized for R-407C
• →5. Leak-test the system at working pressure (around 300 psig)
• →6. Deep evacuate (<500 microns)
• →7. Charge R-407C as liquid (it's a zeotropic blend with glide - liquid charge only)
• →8. Verify superheat and subcool per equipment manual
• →9. Label the system 'Converted to R-407C' with date and tech initials

Expected performance

R-407C performance is 90–95% of original R-22 capacity. Efficiency typically 3–8% lower. Most customers don't notice. Document the conversion - insurance and resale value depend on proper records.