Baker Distributing conducted A2L/R454B Refrigerant classes at their Holly Hill, Sebring, St. Augustine and St, Petersburg facilities in late April 2024.
The three-hour presentations covered refrigerant history, what HFOs are, tools and A2L safety, installation, and service best practices.
Recent refrigerant history for residential HVAC equipment can be summed up as a roadmap to lessening damage to the earth’s atmosphere, starting with the CFC (chlorofluorocarbon) R-12, then R-22, a HCFC (hydrochlorofluorocarbons), both ozone-depleting refrigerants. The replacement for R-22, R-410A, a HFC (hydrofluorocarbon), does not deplete the ozone layer but has a high GWP (Global Warming Potential). The current answer is the A2L (low toxicity, mildly flammable) class of HFO (hydrofluoroolefin) and HFO/HFC blend refrigerants which feature drastically lower GWP and zero ozone depletion. A2L refrigerants offer similar operating characteristics and are more energy efficient than R-410A.
Two A2L refrigerants have been adopted to replace R-410A in new residential and commercial HVAC systems: R-32 and R-454B. Performance, toxicity, flammability and servicing criteria are equal or nearly equal for both refrigerants but R-454B has a lower GWP and generates lower* compressor discharge temperatures than R-32.
Contractors should be aware of changes to the A2L refrigerant cylinders. They will have a permanent red stripe around them indicating it is a flammable gas and left-hand threads for the hose connections. The tanks will have a pressure-relief valve, limiting charge loss, rather than a rupture seal. Tank dimensions will not change but A2L tanks will hold 20 lbs. of refrigerant rather than 25 lbs., due to density of the refrigerant. The cylinders should be stored and transported in an upright position to keep the vapor space in contact with the relief valve.
Technicians should verify that their tools are A2L compliant, and tool manufacturers are making it easy to locate those that are.
Many of the service best practices for A2Ls are the same as for R-410A (A1 refrigerants) but there are 3 that were optional and are now required: 1) Purge circuit with an inert gas (oxygen-free nitrogen), 2) Evacuate the circuit, and 3) perform a leak and pressure test.
Visit the Baker Distributing events calendar (https://www.bakerdist.com/events/) for activities near you.
*NOTE: this reference to lower discharge temperatures was corrected on June 11, 2024. When published May 29, 2024, the post incorrectly indicated that R-454B generated higher discharge temperatures.
