We are in the New Year and the one thing we can be sure of is that the price of R-22 will continue to climb. The EPA still hasn't decided how much production will be cut for 2012 so no one knows what 2013 will bring. The time to start seriously thinking about retrofitting is here so we need to consider our best options. There is a lot of R-22 equipment in the field and there will be for many years to come. You will need to start retrofitting at some point as the R-22 supply goes down and the price continues to go up.
Drop-in retrofits are the easiest to perform. Honeywell's Genetron R-422D and Icor's NU22B are good choices as drop-in replacement refrigerants for R-22. These replacements are called drop-in refrigerants as, in most cases, no oil change or system modifications will be required for close coupled split or packaged A/C systems. To replace the refrigerant: record the system operating data, remove the R-22, replace the filter drier, replace Schrader cores and caps, evacuate the system to 500 microns and weigh in the R-422D. You will add by weight 90% of the amount of R-22 you removed. Check the operation and adjust charge as needed. The system capacity will be slightly less, however, the discharge temperature will be lower. On properly sized equipment the slight capacity loss will be made up for by a slightly longer run time. The cost of the replacement refrigerants is much lower than R-22 and you will use less refrigerant, which will also save your customer money.
Non-drop-in retrofits are a better choice when replacing R-22 in systems when you can't afford the capacity loss. Honeywell's R-407C is a good choice for non-drop-in R-22 replacements. Non-drop-in replacements like R-407C will require some amount of oil change but there will be no capacity loss and lower discharge temperatures. For close coupled split and packaged A/C systems a minimum of 20% POE oil will be required to ensure proper oil return. This is accomplished by removing 20% of the MO and adding that amount of POE oil to the unit. Behler-Young stocks the Nu-Calgon CanVertor (part # 4814-0) that allows the oil to be easily pumped out of the compressor while it is still installed in the A/C unit. During a compressor change out simply dump the MO out of the new compressor and replace it with POE before the compressor is installed. Begin the retrofit by recording normal operational data. Recover the R-22, replace the oil, change the filter drier, replace Schrader cores and caps, evacuate the system to 500 microns and recharge with R-407C. Weigh in 90% of the amount of R-22 that was removed from the system. Check system operation and adjust the system as needed.
When retrofitting always keep in mind that removing chlorinated refrigerants like R-22 will cause some rubber and synthetic components to shrink and leak. All rubber and synthetic seals such as Schrader valve cores and caps or O rings should be replaced while retrofitting to prevent future leaks. More information for retrofitting can be found at Honeywell Genetron's web site: www.honeywell-refrigerants.com