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54

(1) Types and Storage of Piping Materials

Refrigerant piping materials for air conditioners are broadly classified into the following types.

Refrigerant piping
materials

with heat
insulation
without heat
insulation
(bare copper pipe)

with flare processing
without flare processing
without flare processing

General name
: (a) Piping set
: (b) Copper pipe with insulation
: (c) Bare copper pipe

As R410A features pressure about 1.6 times higher than R22, it is necessary to use a copper pipe which has

a thickness stated in Table 3 and which contains less contaminants. It is necessary to carefully treat/store
copper pipes so that they are not collapesd, deformed or damaged. Due care must also be exercised so that
foreign matters such as dust and water do not enter the pipe interior.

A piping set's open end is sealed with a cap, etc. When storing it, make sure that it is sealed securely. When

storing a cladded copper pipe or bare copper pipe, securely seal the opening with pinching, taping, etc.

(2) Identification

a) Piping set

A copper pipe as piping set for R410A must have a thickness as stated in Table 3, and, as shown in Tables
5 and 6, it also differs from R22 in flare processing and flare nut dimensions. So, it is necessary to choose
a piping set suitable for R410A.

b) Copper Pipe with Insulation

Before using a copper pipe with insulation, make sure that is has a thickness designated for R410A.

c) Bare Copper Pipe

It is necessary to use a bare copper pipe which has a thickness desigtnated in Table 3 and contains less
contaminants. As the bare copper pipe surface is naked, it is necessary to treat it with exceeding care and
adopt a means for identification to prevent improper usage by making it easily discriminable from other
piping materials.

(3) Precautions before Installation

Observe the following precautions when performing the piping connection at the site.
a)  Keep any open ends of pipes be sealed with a cap,  etc. until connected with the equipment.
b) Exercise great care when performing piping installation on a rainy day.

When water enters into the piping, the lubricating oil may deteriorate and cause the equipment to fail.

c) Carry out the piping connection in as short a time as possible.

If the piping is left open for a long period, fully purge the interior with nitrogen gas or dry it with a vacuum
pump.

In the case of an air conditioner using R410A, in order to prevent any other refrigerant from being
chargedaccidentally, the service port diameter of the outdoor unit control valve (3-way valve) has been changed.
Also, to increase the pressure resisting strength, flare processing dimensions and sizes of opposite sides of flare
nuts (for copper pipes with nominal diameters 1/2 and 5/8) have been changed. During installation/service,
therefore, prepare tools exclusive for R410A shown in (1) below and general tools shown in (2) on page 48.

(1) Tools Exclusive for R410A

a) Gauge Manifold

As R410A is characterized by high pressure, conventional tools cannot be used.

High pressure
gauge (red)

Conventional gauges

Gauges exclusive for R410A

- 0.1 ~ 3.5 MPa

- 76 cmHg ~ 35 kgf/cm

2

- 0.1 ~ 1.7 MPa

- 76 cmHg ~ 17 kgf/cm

2

- 0.1 ~ 5.3 MPa

- 76 cmHg ~ 53 kgf/cm

2

- 0.1 ~ 3.8 MPa

- 76 cmHg ~ 38 kgf/cm

2

Compound
gauge (blue)

In order to prevent any other refrigerant from being charged accidentally, each port of yhe manifold has
been changed in shape.

55

Port size

Conventional manifold

Manifold for R410A

7/16 UNF

20 threads per inch

1/2 UNF

20 threads per inch

b) Charge Hose

As R410A is characterized by high pressure, the pressure resistance of the charge hose has been
increased. The material has also been changed to an HFC resistant type, and, as is the case of each
port of the manifold, the hose cap size has been changed. Furthermore, for prevention of gas pressure
reaction, a charge hose with a valve placed near the cap is also available.

Pressure
resistance

Conventional charge hose

Charge hose for R410A

3.4 MPa (34 kgf/cm

2

)

17.2 MPa (172 kgf/cm

2

)

NBR rubber

7/16 UNF

20 threads per inch

5.1 MPa (51 kgf/cm

2

)

27.4 MPa (274 kgf/cm

2

)

HNBR rubber

internally coated with nylon

1/2 UNF

20 threads per inch

Engineering material

Normal pressure

Breaking pressure

Cap size

c) Electronic Balance for Refrigerant Charging

As R410A belonging to the HFCs features high pressure and high evaporating speed, when R410A is
charged by using a charging cylinder, R410A in the cylinder cannot be kept in a liquefied state and
gasified  refrigerant bubbles in the charging cylinder, it becomes difficult to read values. Therefore, it is
advisable to adequately use an electronic balance for refrigerant charging.
An electronic balance for refrigerant charging has higher strength due to its structure
with four points of support for refrigerant cylinder weight detection. As the charge hose connecting part
has two ports-one for R22 (7/16 UNF 20 threads per inch) and the other for R410A (1/2 UNF 20 threads
per inch)-it can also be used for charging the conventional refrigerant.
Two types of electronic balance for refrigerant charging are available-one for 10 kg cylinder and the other
for 20 kg cylinder.
Electronic balance for 10 kg cylinder ...... precision 

±

 2g

Electronic balance for 20 kg cylinder ...... precision 

±

 5g

Refrigerant is charged maunally by opening/closing the valve.

d) Torque Wrench (for nominal diameters 1/2 and 5/8)

Along with changes is flare nut sizes for enhanced pressure resisting strength, torque wrenches for
R410A differ in opposite side size.

For 1/2 
(opposite x torque)

For 5/8 
(opposite x torque)

Conventional torque wrench

Torque wrench for R410A

24 mm x 55 N m

(550 kgf cm)

27 mm x 65 N m

(650 kgf cm)

26 mm x 55 N m

(550 kgf cm)

29 mm x 65 N m

(650 kgf cm)

e) Flare Tool (clutch trpe)

A flare tool for R410A is provided with a large clamp bar receiving hole so that the projection of the copper
pipe from the clamp bar can be se at 0 ~ 0.5 mm in flare processing, and also features higher spring
strength for increased expansion pipe torque. This flare tool can also be used for R22 copper pipe.

f)

Gauge for Projection Adjustment (used when flare processing is made by using conventional flare
tool [clutch type] )

A gauge 1.0 mm in thickness which helps in easily setting the projection of the copper pipe from the
clamp bar at 1.0 ~1.5 mm.

g) Vacuum Pump Adapter

It is necessary to use an adapter for preventing vacuum pump oil from flowing back to the charge hose.
The charge hose connecting part has two ports-one for conventional refrigerant (7/16 UNF 20 threads
per inch) and the other for R410A. If the vacuum pump oil (mineral) mixes with R410A, a sludge may
occur and damage the equipment.

56

h) Refrigerant Cylinder

A refrigerant cylinder exclusive for R410A comes identified with refrigerant name and is coated with pink
paint as designated by the ARI, U. S. A

i)

Charge Port and Packing for Refrigerant Cylinder

According to the charge hose's cap size, a charge port with 1/2 UNF 20 threads per inch and
corresponding packing are required.

j)

Gas Leakage Detector

A high sensitivity gas leakage detector exclusive for HFC refrigerant is used. In the case of R410A, the
detection sensitivity is about 23 g per year.

(2) General Tools

a)   Vacuum pump
b)   Torque wrench

for 1/4 : opposite side 17 mm x
for 1/4 : opposite side 17 mm x
for 3/8 : opposite side 22 mm x

c)   Pipe cutter
d)   Reamer
e)   Screwdriver (+,   )
f )   Hacksaw

g)   Hole core drill (Ø65 or 70)
h)   Hexagonal wrench (opposite side 4 or 5 mm)
i )   Spanner, or monkey wrench
j )   Tape measure
k)   Thermometer
l )   Clamping ampere meter

m)  Insulation resistance tester (mege tester)

n)  Electro circuit tester
o)  Pipe bender

(16 N  m)
(160 kgf  cm)

(18 N  m)
180 kgf  cm)
(42 N  m)
(420 kgf  cm)

(3) Applicability or R410A Tools to R22 Model

Gauge manifold

Tools for R410A

Applicable to R22 model

Charge hose

Electronic balance for refrigerant charging
Torque wrench (norminal diameter 1/2, 5/8)

Flare tool (clutch type)

Gauge for projection adjustment

Vacuum pump adapter
Refrigerant cylinder

Charge port and packing for refrigerant cylinder

Gas leakage detector

Used when conventional flare tool (clutch type) is used.

Note: For inquiry, contact your agent.

a)

b)

c)

d)

e)

f)

g)

h)

i)

j)

(1) Air Purge by Vacuum Pump and Gas Leakage Inspection (See Fig. 6)

a) Connect the charge hose to the outdoor unit. 

1

b) Connect the charge hose to the vacuum pump adapter. 

2

At this time, keep the control valves in the fully closed position. 

3

 

4

c) Place the handle Lo in the fully opened position 

5

, and turn ON the vacuum pumpÅfs power switch.

During this step, perform evacuating (about 10~15 minutes); for the evacuating time, refer to the equipment
manufacturer's manual.

d)  When the compound gauge's pointer has indicated -0.1 MPa (-76 cmHg) 

6

, place the handle Lo in the fully

closed position 

5

, and turn OFF the vacuum pump's power switch.

Keep this state for 1 ~ 2 minutes, and ascertain that the compound gauge's pointer does not retum.

e) Fully open the control valves. 

3

 

4

f)

Detach the charge hoses. 

1

 

2

g) Tightly secure the cap on the service port. 

7

57

h) After securing the caps on the control valves, check the capsÅf periphery if there is any gas leakage. 

3

 

4

 

7

(2)  Additional Refrigerant Charging Required for Refrigerant Piping Length Longer Than Standard Length (The

following steps should be taken following the step e) in (1) above. See Fig. 7)

a) Set the refrigerant cylinder to the electronic balance, and connect the connecting hoses on the cylinder and

electronic balanceÅfs connecting port.

Be sure to make setting so that liquid con be charged. When using a cylinder equipped with a siphon, liquid
can be charged without turning it upside down.

b) Connect the gauge manifoldÅfs charge hose to the electronic balanceÅfs connecting port. 

3

 

2

c) Open the refrigerant cylindesÅfs valve, and, after opening the charging valve a little, close it. 

1

 

2

d) After making zero (0) adjustment, open the charging valve and, by opening the gauge maniflod's valve Lo,

charge the liquid refrigerant. 

2

 

5

e) When the designated amount of refrigrant could not be charged, make additional charging bit by bit by cooling

operation (for the amount of each addition, follow the instruction manual prepared by the equipment
manufacturer) . If the first additional charging was not enough, make the second additional charging after about
one miunte in the same manner as the first additional charging.

Be sure never to charge a large amount of liquid refrigerant at once to the unit in cooling mode, since liquid

is charged from the gas siede.

f)

After charging liquid refrigerant into the air conditioner by closing the charging valve, stop operation by fully

closing the gauge manifold's valve Lo. 

2

 

5

g) Quickly remove the charge hose from the service port. 

6

When stopped halfway, refrigerant being cycled will be released.

Compound pressure
gauge

Control valve (2-way)

Control valve 
(3-way)

Service port

Charge hose

Handle Lo

Handle Hi (always closed)

Charge hose

Gauge manifold

Vacuum pump adapter

Vacuum pump

76cmHg

Caution:
      Be sure to use the vacuum pump,
      adapter and gauge manifold to refer to
      tion manuals beforehand.
      Ascertion that the vacuum pump is fille
      the level designated on the oil gauge.

6

5

1

3

4

7

8

2