9. REFRIGERANT R410A:
SPECIAL PRECAUTIONS WHEN SERVICING UNIT
9-1. Characteristics of New Refrigerant R410A
9-1-1. What is New Refrigerant R410A?
R410A is a new refrigerant that contains two types of pseudo-non-azeotropic refrigerant mixture. Its
refrigeration capacity and energy efficiency are about the same level as the conventional refrigerant, R22.
9-1-2. Components (mixing proportions)
HFC32 (50%) / HFC125 (50%)
Less toxic, more chemically stable refrigerant
The composition of refrigerant R410A changes whether it is in a gaseous phase or liquid phase. Thus, when
there is a refrigerant leak the basic performance of the air conditioner may be degraded because of a change in
composition of the remaining refrigerant. Therefore, do not add new refrigerant. Instead, recover the
remaining refrigerant with the refrigerant recovery unit. Then, after evacuation, totally recharge the specified
amount of refrigerant with the new refrigerant at its normal mixed composition state (in liquid phase).
When refrigerant R410A is used, the composition will differ depending on whether it is in gaseous or liquid
phase, and the basic performance of the air conditioner will be degraded if it is charged while the refrigerant is in
gaseous state. Thus, always charge the refrigerant while it is in liquid phase.
9-2. Checklist before Servicing
Use a clutch-type flare tool for R410A or the conventional flare tool. Note that sizes of the resultant flares differ
between these two tools. Where a conventional flare tool is used, make sure to observe A Specification (amount of
extrusion) by using the flare spacer.
Diameter of tube D
Dia.6.35 mm (1/4")
Dia.9.52 mm (3/8")
Dia.12.7 mm (1/2")
Dia.15.2 mm (5/8")
Size of flare
Ether-type oil is used for compressor oil for R410A-type units, which is different
from the mineral oil used for R22. Thus more attention to moisture prevention and
faster replacement work compared with conventional models are required.
Flare tool for R410A
0 to 0.5 mm
Flare tool for R410A
Conventional flare tool (for R22)
Conventional flare tool (R22)