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8. Electronic scale for refrigerant charging
• Because of the high pressure and fast vaporizing speed
of R410A, the refrigerant cannot be held in a liquid phase
inside the charging cylinder when charging is done using
the charging cylinder method, causing bubbles to form in
the measurement scale glass and making it difficult to
see the reading. (Naturally, the conventional R22
charging cylinder cannot be used because of the
differences in the pressure resistance, scale gradation,
connecting port size, etc.)
inside the charging cylinder when charging is done using
the charging cylinder method, causing bubbles to form in
the measurement scale glass and making it difficult to
see the reading. (Naturally, the conventional R22
charging cylinder cannot be used because of the
differences in the pressure resistance, scale gradation,
connecting port size, etc.)
• The electronic scale has been strengthened by using a
structure in which the weight detector for the refrigerant
cylinder is held by four supports. It is also equipped with
two connection ports, one for R22 (7/16 UNF, 20
threads) and one for R410A (1/2 UNF, 20 threads), so it
can also be used for conventional refrigerant charging.
cylinder is held by four supports. It is also equipped with
two connection ports, one for R22 (7/16 UNF, 20
threads) and one for R410A (1/2 UNF, 20 threads), so it
can also be used for conventional refrigerant charging.
• There are two types of electronic scales, one for 10-kg
cylinders and one for 20-kg cylinders. (The 10-kg
cylinder is recommended.)
Refrigerant charging is done manually by opening and
closing the valve.
cylinder is recommended.)
Refrigerant charging is done manually by opening and
closing the valve.
9. Refrigerant cylinders
• The R410A cylinders are labeled with the refrigerant
name, and the coating color of the cylinder protector is
pink, which is the color stipulated by ARI of the U.S.
pink, which is the color stipulated by ARI of the U.S.
• Cylinders equipped with a siphon tube are available to
allow the cylinder to stand upright for liquid refrigerant
charging.
charging.
10. Charging orifice and packing for refrigerant cylinders
• The charging orifice must match the size of the charging
hose fitting (1/2 UNF, 20 threads).
• The packing must also be made of an HFC-resistant
material.
Fig. 7 Electronic scale for refrigerant charging
Fig. 8 Refrigerant cylinders
Fig. 9 Charging orifice and packing
11.2.3.
R410A tools which are usable for R22 models
Table 9 R410A tools which are usable for R22 models
R410A tools
Usable for R22 models
(1)
Copper tube gauge for clearance adjustment
OK
(2)
Flaring tool (clutch type)
OK
(3)
Manifold gauge
NG
(4)
Charging hose
NG
(5)
Vacuum pump adaptor
OK
(6)
Electric gas leak detector for HFC refrigerant
NG
(7)
Electronic scale for refrigerant charging
OK
(8)
Refrigerant cylinder
NG
(9)
Charging orifice and packing for refrigerant cylinder
NG
94
11.3. Refrigerant piping work
11.3.1.
Piping materials
It is recommended that you use copper and copper alloy jointless pipes with a maximum oil adherence of 40 mg/10m. Do not use
pipes that are crushed, deformed, or discolored (especially the inside surface). If these inferior pipes are used, impurities may clog
the expansion valves or capillaries.
Because the pressure of ACs using R410A is higher than those using R22, it is essential that you select materials that are
appropriate for these standards.
The thickness of the copper tubing used for R410A is shown in Table 10. Please be aware that tubing with a thickness of only 0.7
mm is also available on the market, but this should never be used.
pipes that are crushed, deformed, or discolored (especially the inside surface). If these inferior pipes are used, impurities may clog
the expansion valves or capillaries.
Because the pressure of ACs using R410A is higher than those using R22, it is essential that you select materials that are
appropriate for these standards.
The thickness of the copper tubing used for R410A is shown in Table 10. Please be aware that tubing with a thickness of only 0.7
mm is also available on the market, but this should never be used.
Table 10 Copper tube thickness (mm)
11.3.2.
Processing and connecting piping materials
When working with refrigerant piping, the following points must
be carefully observed: no moisture or dust must be allowed to
enter the piping, and there must be no refrigerant leaks.
be carefully observed: no moisture or dust must be allowed to
enter the piping, and there must be no refrigerant leaks.
1. Procedure and precautions for flaring work
a. Cut the pipe
Use a pipe cutter, and cut slowly so the pipe will not
be deformed.
be deformed.
b. Remove burrs and clean shavings from the cut
surface
If the shape of the pipe end is poor after removing
burrs, or if shavings adhere to the flared area, it may
lead to refrigerant leaks.
To prevent this, turn the cut surface downward and
remove burrs, then clean the surface, carefully.
If the shape of the pipe end is poor after removing
burrs, or if shavings adhere to the flared area, it may
lead to refrigerant leaks.
To prevent this, turn the cut surface downward and
remove burrs, then clean the surface, carefully.
c. Insert the flare nut (be sure to use the same nut that is
used on the AC unit)
d. Flaring
Check the clamp bar and the cleanliness of the
copper pipe.
Be sure to use the clamp bar to do the flaring with
accuracy. Use either an R410A flaring tool, or a
conventional flaring tool. Flaring tools come in
different sizes, so be sure to check the size before
using. When using a conventional flaring tool, use the
copper pipe gauge for clearance adjustment, etc., to
ensure the correct A dimension (see Fig. 10)
copper pipe.
Be sure to use the clamp bar to do the flaring with
accuracy. Use either an R410A flaring tool, or a
conventional flaring tool. Flaring tools come in
different sizes, so be sure to check the size before
using. When using a conventional flaring tool, use the
copper pipe gauge for clearance adjustment, etc., to
ensure the correct A dimension (see Fig. 10)
Fig. 10 Flaring dimensions
Fig. 11 Relation between the flare nut structure and flaring tool end
Soft pipe
Thickness (mm)
Nominal diameter
Outside diameter (mm)
R410A
(Reference) R22
1/4
6.35
0.80
0.80
3/8
9.52
0.80
0.80
1/2
12.7
0.80
0.80
5/8
15.88
1.00
1.00
95
Table 11 R410A flaring dimensions
Table 12 R22 flaring dimensions
Table 13 R410A flare and flare nut dimensions Unit: mm
Table 14 R22 flare and flare nut dimensions Unit: mm
2. Procedure and precautions for flare connection
a. Check to make sure there is no scratches, dust, etc., on the flare and union.
b. Align the flared surface with the axial center of the union.
b. Align the flared surface with the axial center of the union.
c. Use a torque wrench, and tighten to the specified torque. The tightening torque for R410A is the same as the conventional
torque value for R22. Be careful, because if the torque is too weak, it may lead to a gas leak. If it is too strong, it may split
the flare nut or make it impossible to remove the flare nut.
the flare nut or make it impossible to remove the flare nut.
Table 15 R410A tightening torque
11.3.3.
Storing and managing piping materials
1. Types of piping and their storage
The following is a general classification of the refrigerant pipe materials used for ACs.
Because the gas pressure of R410A is approximately 1.6 times as high as that of R22, copper pipes with the thickness shown
in Table 10, and with minimal impurities must be used. Care must also be taken during storage to ensure that pipes are not
crushed, deformed, or scratched, and that no dust, moisture or other substance enters the pipe interior. When storing
sheathed copper pipes or plain copper pipes, seal the openings by pinching or taping them securely.
in Table 10, and with minimal impurities must be used. Care must also be taken during storage to ensure that pipes are not
crushed, deformed, or scratched, and that no dust, moisture or other substance enters the pipe interior. When storing
sheathed copper pipes or plain copper pipes, seal the openings by pinching or taping them securely.
2. Makings and management
a. Sheathed copper pipes and copper-element pipes
When using these pipes, check to make sure that they are the stipulated thickness. For flare nuts, be sure to used the
same nut that is used on the AC unit.
same nut that is used on the AC unit.
Nominal
diameter
Outside
diameter
(mm)
Wall thickness
(mm)
A (mm)
R410A flaring
tool, clutch type
Conventional flaring tool
Clutch type
Wing-nut type
1/4
6.35
0.8
0 - 0.5
1.0 - 1.5
1.5 - 2.0
3/8
9.52
0.8
0 - 0.5
1.0 - 1.5
1.5 - 2.0
1/2
12.70
0.8
0 - 0.5
1.0 - 1.5
2.0 - 2.5
5/8
15.88
1.0
0 - 0.5
1.0 - 1.5
2.0 - 2.5
Nominal
diameter
Outside
diameter
(mm)
Wall thickness
(mm)
A (mm)
R22 flaring
tool, clutch type
Conventional flaring tool
Clutch type
Wing-nut type
1/4
6.35
0.8
0 - 0.5
0.5 - 1.0
1.0 - 1.5
3/8
9.52
0.8
0 - 0.5
0.5 - 1.0
1.0 - 1.5
1/2
12.70
0.8
0 - 0.5
0.5 - 1.0
1.5 - 2.0
Nominal
diameter
Outside
diameter (mm)
Wall thickness
(mm)
A +0, -0.4
B
dimension
C
dimension
D
dimension
Flare nut
width
1/4
6.35
0.8
9.1
9.2
6.5
13
17
3/8
9.52
0.8
13.2
13.5
9.7
20
22
1/2
12.70
0.8
16.6
16.0
12.9
23
26
5/8
15.88
1.0
19.7
19.0
16.0
25
29
Nominal
diameter
Outside
diameter (mm)
Wall thickness
(mm)
A +0, -0.4
B
dimension
C
dimension
D
dimension
Flare nut
width
1/4
6.35
0.8
9.0
9.2
6.5
13
17
3/8
9.52
0.8
13.0
13.5
9.7
20
22
1/2
12.70
0.8
16.2
16.0
12.9
20
24
Nominal
diameter
Outside
diameter (mm)
Tightening torque
N.m (kgf.cm)
Torque wrench tightening torque
N.m (kgf.cm)
1/4
6.35
14 - 18 (140 - 180)
18 (180)
3/8
9.52
33 - 42 (330 -420)
42 (420)
1/2
12.70
55 (550)
55 (550)
5/8
15.88
65 (650)
65 (650)
96
b. Copper pipes
Use only copper pipes with the thickness given in table 10, and with minimal impurities. Because the surface of the pipe is
exposed, you should take special care, and also take measures such as marking the pipes to make sure they are easily
distinguished from other piping materials, to prevent mistaken use.
exposed, you should take special care, and also take measures such as marking the pipes to make sure they are easily
distinguished from other piping materials, to prevent mistaken use.
3. Precautions during refrigerant piping work
Take the following precautions on-site when connecting pipes. (Keep in mind that the need to control the entry of moisture and
dust is even more important that in conventional piping).
dust is even more important that in conventional piping).
a. Keep the open ends of all pipes sealed until connection with AC equipment is complete.
b. Take special care when doing piping work on rainy days. The entering of moisture will degrade the refrigerating machine
b. Take special care when doing piping work on rainy days. The entering of moisture will degrade the refrigerating machine
oil, and lead to malfunctions in the equipment.
c. Complete all pipe connections in as short a time as possible. If the pipe must be left standing for a long time after removing
the seal, it must be thoroughly purged with nitrogen, or dried with a vacuum pump.
11.4. Installation, transferring, servicing
11.4.1.
Inspecting gas leaks with a vacuum pump for new installations (Using new
refrigerant piping)
refrigerant piping)
1. From the viewpoint of protecting the global environment, please do not release refrigerant into the atmosphere.
a. Connect the projecting side (pin-pushing side) of the charging hose for the manifold gauge to the service port of the 3-way
valve. (1)
b. Fully open the handle Lo of the manifold gauge and run the vacuum pump. (2) (If the needle of the low-pressure gauge
instantly reaches vacuum, re-check step a).)
c. Continue the vacuum process for at least 15 minutes, then check to make sure the low-pressure gauge has reached -0.1
MPa (-76 cmHg). Once the vacuum process has finished, fully close the handle Lo of the manifold gauge and stop the
vacuum pump operation, then remove the charging hose that is connected to the vacuum pump adaptor. (Leave the unit in
that condition for 1-2 minutes, and make sure that the needle of the manifold gauge does not return.) (2) and (3)
vacuum pump operation, then remove the charging hose that is connected to the vacuum pump adaptor. (Leave the unit in
that condition for 1-2 minutes, and make sure that the needle of the manifold gauge does not return.) (2) and (3)
d. Turn the valve stem of the 2-way valve 90
° counter-clockwise to open it, then, after 10 seconds, close it and inspect for a
gas leak (4)
e. Remove the charging hose from the 3-way valve service port, then open both the 2-way valve and 3-way valve. (1) (4)
(Turn the valve stem in the counter-clockwise direction until it gently makes contact. Do not turn it forcefully).
f. Tighten the service port cap with a torque wrench (18 N.m (1.8 kgf.m)). (5) Then tighten the 2-way valve and 3-way valve
caps with a torque wrench (42 N.m (4.2 kgf.m)) or (55 N.m (5.5 kgf.m)). (6)
g. After attaching each of the caps, inspect for a gas leak around the cap area. (5) (6)
Precautions
• Be sure to read the instructions for the vacuum pump,
vacuum pump adaptor and manifold gauge prior to use, and
follow the instructions carefully.
follow the instructions carefully.
• Make sure that the vacuum pump is filled with oil up to the
designated line on the oil gauge.
• The gas pressure back flow prevention valve on the
charging hose is generally open during use. When you are
removing the charging hose from the service port, it will
come off more easily if you close this valve.
removing the charging hose from the service port, it will
come off more easily if you close this valve.
Fig. 12 Vacuum pump air purging configuration
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