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SM830092
12. SERVICE PROCEDURES
11. REFRIGERANT R410A: SPECIAL PRECAUTIONS WHEN INSTALLING UNIT
11-1. Characteristics of New Refrigerant R410A
11-1-1. What is New Refrigerant R410A?
R410A is a new refrigerant that contains two types of pseudo-non-azeotropic refrigerant mixture which do
not adversely affect the earth’s ozone layer. Its refrigeration capacity and energy efficiency are about the
same level as the conventional refrigerant, R22.
11-1-2. Components (mixing proportions)
HFC32 (50%) / HFC125 (50%)
11-1-3. Characteristics
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.
11-2. Checklist Before Installation
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 protrusion).
Size of flare
CAUTION
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.
Diameter of tube (ø) D
A Specification
Flare tool for R410A Conventional flare tool (for R22)
ø6.35 (1/4") 0 – 0.5 mm 1.0 – 1.5 mm
ø19.05 (3/4") 0 – 0.5 mm 1.0 – 1.5 mm
A
D
Flare tool for R410A
A
Conventional flare tool (R22)
D
Flare nut: Because the new refrigerant R410A operates at 1.6 times higher pressure than the conventional
refrigerant R22, the flare nuts that came with the unit must be used.