refrigerant comparison chartAs the HVACR industry continues to move away from HCFC-22 due to regulatory pressures, one of the new retrofit options for such systems is HFC-427A.

As described by the refrigerant manufacturer Arkema, “R-427A (which Arkema markets as Forane 427A) is an easy to use, non-ozone depleting HFC refrigerant, which, in addition to having comparable performance to R-22, has one of the lower global warming potentials of the R-22 retrofit refrigerants available today.”

A Case in Canada

An example of the use of the refrigerant is by Airco Mechanical Services to retrofit an air conditioning system for the computer server at the Canada Revenue Agency in Sudbury, Ontario. With Airco servicing a wide variety of equipment in the northern Ontario area, its president, Chip Richter, said he learned of R-427A through wholesaler TML Supply Ltd. Richter said he was “looking for a good, all-around R-22 retrofit to help customers through the industry’s transition away from ozone depleting substances.”

Server Room

The server room at the agency is cooled by two identical air conditioning systems. One of the systems was retrofitted with R-427A so that a side-by-side comparison of system properties and performance could be made with R-22.

Each system utilizes two individual circuits, powered by reciprocating compressors. Reclaim systems were being used to capture high-side heat rejection for domestic water heating.

The retrofit was performed by Airco service technicians with engineers from the refrigerant supplier, Arkema, on site for support. After recovering the R-22 charge, the compressor mineral oil was drained and refilled with POE oil. The filter drier was replaced as a standard maintenance practice. The system was evacuated.

Once the system was charged with R-427A, the server room cooled down rapidly, Richter said. He noted that no adjustments to the expansion valves, pressure controls, or other settings were required.

The closeness of the operating characteristics of R-427A to R-22 was critical for the application, it was reported, as the systems are run at fixed head pressure to maximize the effectiveness of the heat reclaim loops (see chart below).


According to those involved in the project, the server room operated normally with no noticeable difference in cooling performance. Operating pressures of the systems were nearly identical for both refrigerants. A 40˚F decrease in compressor discharge temperatures and lower compressor current draws were also observed after switching to R-427A. When asked about the refrigerant, Richter said, “I rate it a 10 and will absolutely recommend it to my other customers.”

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Publication date: 10/31/2011