6
(2) Cautions for refrigerant piping work
New refrigerant R410A is adopted for replacement inverter series. Although the refrigerant piping work for R410A is same
as for R22, exclusive tools are necessary so as not to mix with different kind of refrigerant. Furthermore as the working
pressure of R410A is 1.6 time higher than that of R22, their sizes of flared sections and flare nuts are different.
1
Thickness of pipes
Because the working pressure of R410A is higher compared to R22, be sure to use refrigerant piping with thickness
shown below. (Never use pipes of 0.7mm or below.)
2
Dimensions of flare cutting and flare nut
The component molecules in HFC refrigerant are smaller compared to conventional refrigerants. In addition to that,
R410A is a refrigerant, which has higher risk of leakage because of its working pressure higher than that of other refriger-
ants. Therefore, to enhance airtightness and intensity, flare cutting dimension of copper pipe for R410A have been speci-
fied separately from the dimensions for other refrigerants as shown below. The dimension B of flare nut for R410A also
have partly been changed to increase intensity as shown below. Set copper pipe correctly referring to copper pipe flaring
dimensions for R410A below. For 1/2” and 5/8”, the dimension B changes.
Use torque wrench corresponding to each dimension.
3
Tools for R410A (The following table shows whether conventional tools can be used or not.)
1/4”
3/8”
1/2”
5/8”
3/4”
6.35
9.52
12.70
15.88
19.05
0.8
0.8
0.8
1.0
—
0.8
0.8
0.8
1.0
1.0
Nominal
dimensions
Diagram below: Piping diameter and thickness
Outside
diameter (mm)
Thickness (mm)
R410A
R22
1/4”
3/8”
1/2”
5/8”
3/4”
6.35
9.52
12.70
15.88
19.05
9.1
13.2
16.6
19.7
—
9.0
13.0
16.2
19.4
23.3
Nominal
dimensions
Flare cutting dimensions
Outside
diameter
Dimension A ( )
+0
-0.4
(mm)
R410A
R22
1/4”
3/8”
1/2”
5/8”
3/4”
6.35
9.52
12.70
15.88
19.05
17.0
22.0
26.0
29.0
—
17.0
22.0
24.0
27.0
36.0
Nominal
dimensions
Flare nut dimensions
Outside
diameter
Dimension B
(mm)
R410A
w
w
36.0mm for
indoor unit
of RP4, 5
and 6
R22
Gauge manifold
Charge hose
Gas leak detector
Refrigerant recovery equipment
Refrigerant cylinder
Applied oil
Safety charger
Charge valve
Vacuum pump
Flare tool
Bender
Pipe cutter
Welder and nitrogen gas cylinder
Refrigerant charging scale
Vacuum gauge or thermis-
tor vacuum gauge and
vacuum valve
Charging cylinder
Air purge and refrigerant charge
Operation check and the two above
Gas leak check
Collection of refrigerant
Refrigerant charge
Apply to flared section
Prevent compressor malfunction
when charging refrigerant by
spraying liquid refrigerant
Prevent gas from blowing out
when detaching charge hose
Vacuum drying and air
purge
Flaring work of piping
Bend the pipes
Cut the pipes
Weld the pipes
Charge refrigerant
Check the degree of vacuum. (Vacuum
valve prevents back flow of oil and refri-
gerant to thermistor vacuum gauge)
Charge refrigerant
Tool exclusive for R410A
Tool exclusive for R410A
Tool for HFC refrigerant
Tool exclusive for R410A
Tool exclusive for R410A
Ester oil and alkylbenzene
oil (minimum amount)
Tool exclusive for R410A
Tool exclusive for R410A
Tools for other refrigerants can
be used if equipped with adop-
ter for reverse flow check
Tools for other refrigerants
can be used by adjusting
flaring dimension
Tools for other refrigerants can be used
Tools for other refrigerants can be used
Tools for other refrigerants can be used
Tools for other refrigerants can be used
Tools for other refrigerants
can be used
Tool exclusive for R410A
Tools and materials
Use
R410A tools
Can R22 tools be used?
(Usable if equipped
with adopter for rever-
se flow)
(Usable by adjusting
flaring dimension)
Can R407C tools be used?
Ester oil:
Alkylbenzene oil: minimum amount
(Usable if equipped
with adopter for rever-
se flow)
(Usable by adjusting
flaring dimension)
: Prepare a new tool. (Use the new tool as the tool exclusive for R410A.)
: Tools for other refrigerants can be used under certain conditions.
: Tools for other refrigerants can be used.
Dimension A
Dimension B
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