5
OCH668G
Cautions for refrigerant piping work
New refrigerant R410A is adopted for replacement inverter series. Although the refrigerant piping work for R410A is the
same as for R22, exclusive tools are necessary so as not to mix with different kind of refrigerant. Furthermore as the work
-
ing pressure of R410A is 1.6 times 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 0.7 mm 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 its working pressure is higher than that of other refrigerants.
Therefore, to enhance airtightness and strength, flare cutting dimension of copper pipe for R410A has been specified sepa
-
rately from the dimensions for other refrigerants as shown below. The dimension B of flare nut for R410A also has partly
been changed to increase strength as shown below. Set copper pipe correctly referring to copper pipe flaring dimensions for
R410A below. For 1/2 and 5/8 inch pipes, the dimension B changes.
Use torque wrench corresponding to each dimension.
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 (in)
Diagram below: Piping diameter and thickness
Outside
diameter (mm)
Thickness (mm)
R410A
R22
Dimension A
Dimension B
Flare cutting dimensions
Flare nut dimensions
Nominal
dimensions (in)
Outside
diameter (mm)
Dimension A
(
+0
-0.4
)
(mm)
Nominal
dimensions (in)
Outside
diameter (mm)
Dimension B (mm)
R410A
R22
R410A
R22
1/4
6.35
9.1
9.0
1/4
6.35
17.0
17.0
3/8
9.52
13.2
13.0
3/8
9.52
22.0
22.0
1/2
12.70
16.6
16.2
1/2
12.70
26.0
24.0
5/8
15.88
19.7
19.4
5/8
15.88
29.0
27.0
3/4
19.05
—
23.3
3/4
19.05
—
36.0
3
Tools for R410A (The following table shows whether conventional tools can be used or not.)
Tools and materials
Use
R410A tools
Can R22 tools be used? Can R407C tools be used?
Gauge manifold
Air purge, refrigerant charge
and operation check
Tool exclusive for R410A
×
×
Charge hose
Tool exclusive for R410A
×
×
Gas leak detector
Gas leak check
Tool for HFC refrigerant
×
○
Refrigerant recovery equipment Refrigerant recovery
Tool exclusive for R410A
×
×
Refrigerant cylinder
Refrigerant charge
Tool exclusive for R410A
×
×
Applied oil
Apply to flared section
Ester oil, ether oil and alkylbenzene
oil (minimum amount)
×
Ester oil, ether oil:
○
Alkylbenzene oil: minimum amount
Safety charger
Prevent compressor malfunction
when charging refrigerant by
spraying liquid refrigerant
Tool exclusive for R410A
×
×
Charge valve
Prevent gas from blowing out
when detaching charge hose
Tool exclusive for R410A
×
×
Vacuum pump
Vacuum drying and air purge
Tools for other refrigerants
can be used if equipped with
adapter for reverse flow check
( Usable if equipped
with adapter for
reverse flow)
(
Usable if equipped with
adapter for reverse flow)
Flare tool
Flaring work of piping
Tools for other refrigerants can be
used by adjusting flaring dimension
( Usable by
adjusting flaring
dimension)
(
Usable by adjusting
flaring dimension)
Bender
Bend the pipes
Tools for other refrigerants can be used
○
○
Pipe cutter
Cut the pipes
Tools for other refrigerants can be used
○
○
Welder and nitrogen gas
cylinder
Weld the pipes
Tools for other refrigerants can be used
○
○
Refrigerant charging scale
Refrigerant charge
Tools for other refrigerants can be used
○
○
Vacuum gauge or thermistor
vacuum gauge and vacuum
valve
Check the degree of vacuum. (Vacuum
valve prevents back flow of oil and refri-
gerant to thermistor vacuum gauge)
Tools for other refrigerants can be used
○
○
Charging cylinder
Refrigerant charge
Tool exclusive for R410A
×
-
×
: 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.
