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Alternatives to R-22 Refrigerants

Technician with refrigerant and vacuum pump

Before proceeding with the information in this article, please refer to this section from the EPA guidelines on refrigerants:

EPA regulations (40 CFR Part 82, Subpart F) under Section 608 of the Clean Air Act require that technicians who maintain, service, repair, or dispose of equipment that could release ozone depleting refrigerants into the atmosphere must be certified. Starting on January 1, 2018, this requirement will also apply to appliances containing most substitute refrigerants, including HFCs.

Technicians are required to pass an EPA-approved test to earn Section 608 Technician Certification. The tests are specific to the type of equipment the technician seeks to work on. Tests must be administered by an EPA-approved certifying organization. Section 608 Technician Certification credentials do not expire. Core tests taken as an open book exam cannot be used to get your Universal Certification. The core test must be taken as a proctored exam in order to attain Universal Certification. 

With the production and importation of the R-22 (hydrochlorofluorocarbon – HCFC – 22) refrigerant ceasing in 2020, now’s the time to schedule refrigeration/freezer maintenance. Afterward, supplies of those refrigerants will decline and costs will rise. Once the remaining virgin stock is depleted, R-22 will only be legally available from EPA-certified refrigerant reclaimers.

Refrigeration repair technicians do have alternatives, however, that let them provide equal or even better cooling using refrigerants in the Environmental Protection Agency’s Significant New Alternatives Policy (SNAP).

The EPA has a list of 70 alternatives – albeit, with specific use conditions – for stand-alone refrigerators and freezers, and more than 50 alternatives to retrofit commercial ice machines. Whatever you choose, it’s important not to mix refrigerants. Therefore, all R22 first must be recovered by an EPA-certified recovery specialist before the unit is recharged.

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Exchanging one coolant for another isn’t as challenging as it used to be, but it’s rarely a straight swap. Before making a change, be sure to check with the refrigerator or freezer manufacture for recommendations and to ensure your choice of refrigerant doesn’t void any warranties. Also, record performance data as a baseline for later comparisons.

Bottles of commercial equipment refrigerant

Here’s a look at some of the best alternatives to R-22 and some of their characteristics.

R-422C (One Shot-C®)is versatile, replacing R-22 for low- and medium-temperature uses, as well as R-402A, R-402B, R-404A, R-408A, R-502, and R-507A for other applications. It is designed for all mineral oil, alkylbenzene, and polyolester lubricants. During retrofits, replace o-rings and gaskets to prevent leaks as they shrink. Also reset the low pressure control and the evaporator or crankcase pressure regulator and confirm fan cycling setpoints.

R-438A (Freon™ MO99™) offers pressure enthalpy characteristics that are similar to those of R-22. Some users report that compressor discharge temperatures actually are lower than those generated by R-22, making it a good choice for frequently-opened units, such as grocery cases. Retrofitting a system with R-438A involves recovering the R-22, replacing filters and critical seals (Schrader valve core seals, for example), charging the refrigerant, restarting the system, and monitoring it for any leaks.

R-422B (NU-22B™) for medium- and high-temperature refrigeration, closely resembles R-22 in functionality. Even the same lubricants – mineral oil, alkylbenzene, polyolester, and polyvinylether – can be used. There are some differences, however. When replacing an R-22 system with R-422B, only charge the system to 95 percent of the R22 level. The refrigerant charge may need to be adjusted to deliver its best performance. Also check the superheat, following the dew point on the pressure/temperature (P/T) chart. After the refrigerator or freezer is converted, it will run longer, but at lower amps, making it more energy efficient. Humidity also will be reduced. For best performance, the seals and thermostatic expansion valve may need adjusting.

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R-428A is another option for low temperature units, but comes with some caveats. Switching means using more R-428A than the R-22 it is replacing, so the system must have the capacity to hold it, as well as the ability to work under pressures more common with R-502.

Other alternatives to R-22 for refrigerators and freezers include R-402A, R-402B, and R-434A.


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  1. Your missing a couple of very important and very popular ones.

    407A, 407C are very popular right now.

    It’s also important to know that there is and always will be some sort of capacitance change, could be more, could be less.
    In some applications, more capacity means less run time, this will increase humidity in the box and in some cases, cause an accelerated failure of a compressor due to short cycling.

    Retrofit’s are not an easy thing to do, if done right, the system will perform almost exactly the same as it did before, unless you DO want more capacity, normally you can get it. There’s also a point of retrofitting into blends, now you’ll see fractionation if there’s a leak or you’ll run into a point of now having zeotropic properties which will also affect the refrigerants efficiency and HAS to be accounted for.

    I spent a long time reading Mollier charts on R22, 404A, R134A, 410A, 407C,407A,MO99 and a couple more to see the difference and there is a difference.