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51

(3) Lubricationg Oils for R410A

As the lubricating oils for R22, mineral oils, alkylbenze synthetic oils, etc. have so far been used. As R410A
features less solubility with these conventional lubricating oils such as mineral oils, the lubricating oils tend
to stay within the refrigeration cycle. As the lubricating oils highly soluble with R410A, ester, ethereal and
other synthetic oils are available. However, as these synthetic oils are very hygroscopic, they must be
treated even more carefully than the conventional lubricating oils. Furthermore, if these synthetic oils are
mixed with mineral oils, alkylbenzene synthetic oils, etc., they may deteriorate, and block the capillary
tubes, or cause the compressor to fail. So, never mix these synthetic oils.

As R410A's pressure is about 1.6 times higher than that of R22, improper installation/servicing may cause a
serious trouble. By using tools and materials exclusive for R410A, it is necessary to carry out installation/servicing
safely while taking the following precautions into consideration.
1) Never use refrigerant other than R410A in an air conditioner which is designed to operate with R410A.
2) If a refrigeration gas leakage occurs during installation/servicing, be sure to ventilate fully.

If the refrigerant gas comes into contact with fire, a poisonous gas may occur.

3) When installing or removing an air conditioner, do not allow air or moisture to remain in the refrigeration cycle.

Otherwise, pressure in the refrigeration cycle may become abnormally high so that a rupture or personal injury
may be caused.

4) After completion of installation work, check to make sure that there is no refrigeration gas leakage.

If the refrigerant gas leaks into the room, coming into contact with fire in the fandriven heater, space heater,
etc., a poisonous gas may occur.

5) When an air conditioning system charged with a large volume of refrigerant (e. g. multi type air conditioner) is

installed in a small room, it is necessary to exercise care so that, even when refrigerant leaks, its concentration
does not exceed the marginal level.
If teh refrigerant gas leakage occurs and its concentration exceeds the marginal level, an oxygen starvation
accident may result.

6) Be sure to carry out installation or removal according to the installation manual. Improper installation may

cause refrigeration troule, water leakage, electric shock, fire, etc.

7) Unauthorized modifications to the air conditioner may be dangerous. If a breakdown occurs please call a

qualified air conditioner technician or electrician.
Improper repair's may result in water leakage, electric shock and file, etc.

For the refrigerant piping installation, copper pipes and joints are mainly used. Copper pipes and joints suitable for
the refrigerant must be chosen and installed. Furthermore, it is necessary to use clean copper pipes and joints
whose interior surfaces are less affected by contaminants.

(1) Copper Pipes

It is necessary to use seamless copper pipes which are made of either copper or copper alloy and it is
desirable that the amount of residual oil is less than 40 mg/10m. Do not use copper pipes having a collapsed,
deformed or discolored portion (especially on the interior surface). Otherwise, the expansion valve or capillary
tube may become blocked with contaminants.
As an air conditioner using R410A incurs pressure higher than when using R22, it is necessary to choose
adequate materials.
Thicknesses of copper pipes used with R410A are as shown in Table 3. Never use copper pipes thinner than
0.8 mm even when it is available on the market.

Normal diameter

Thicknesses (mm)

Outer diameter (mm)

[ref.] R22

6.35

0.80

9.52

0.80

12.70

0.80

15.88

1.00

R410

0.80

0.80

0.80

1.00

1/4

3/8

1/2

5/8

52

When performing the refrigerant piping installation, care should be taken to ensure that water or dust does
not enter the pipe interior, that no other oil other than lubricating oils used in the installed air conditioner is
used, and that refrigerant does not leak. When using lubricating oils in the piping processing, use such
lubricating oils whose water content has been removed. When stored, be sure to seal the container with an
airtight cap or any other cover.
(1) Flare Processing Procedures and Precautions

a) Cutting the Pipe

By means of a pipe cutter, slowly cut the pipe so that it is not deformed.

b) Removing Burrs and Chips

If the flared section has chips or burrs, refrigerant leakage may occur. Carefully remove all burrs and
clean the cut surface before installation.

c) Insertion of Flare Nut
d) Flare Processing

Make certain that a clamp bar and copper pipe have been cleaned.
By means of the clamp bar, perform the flare processing correctly.
Use either a flare tool for R410A or conventional flare tool.
Flare processing dimensions differ according to the type of flare
tool. Be careful. When using a conventional flare tool, be sure to
secure "dimension A" by using a gage for size adjustment.

Norminal 

diameter

Norminal 

diameter

(mm)

A (mm)

Conventional flare tool

Clutch type

Wing nut type

1.5 ~ 2.0

1.5 ~ 2.0

2.0 ~ 2.5

2.0 ~ 2.5

1.0 ~ 1.5

1.0 ~ 1.5

1.0 ~ 1.5

1.0 ~ 1.5

0 ~ 0.5

0 ~ 0.5

0 ~ 0.5

0 ~ 0.5

Flare tool fot R410A

Clutch type

1/4

6.35

9.52

12.70

15.88

Thickness

(mm)

0.8

0.8

0.8

1.0

3/8

1/2

5/8

Norminal 

diameter

Norminal 

diameter

(mm)

A (mm)

Conventional flare tool

Clutch type

Wing nut type

1.0 ~ 1.5

1.0 ~ 1.5

1.5 ~ 2.0

1.5 ~ 2.0

0.5 ~ 1.0

0.5 ~ 1.0

0.5 ~ 1.0

0.5 ~ 1.0

0 ~ 0.5

0 ~ 0.5

0 ~ 0.5

0 ~ 0.5

Flare tool fot R410A

Clutch type

1/4

6.35

9.52

12.70

15.88

Thickness

(mm)

0.8

0.8

0.8

1.0

3/8

1/2

5/8

Norminal 

diameter

Norminal 

diameter

(mm)

Dimension (mm)

Flare nut 

width

9.1

13.2

16.6

19.7

A

9.2

13.5

16.0

19.0

B

6.5

9.7

12.9

16.0

C

13

17

22

26

29

20

23

25

D

1/4

6.35

9.52

12.70

15.88

Thickness

(mm)

0.8

0.8

0.8

1.0

3/8

1/2

5/8

[Unit: mm]

ØD

A

53

Norminal 

diameter

Norminal 

diameter

(mm)

Dimension (mm)

Flare nut 

width

9.0

13.0

16.2

19.4

A

9.2

13.5

16.0

19.0

B

6.5

9.7

12.9

16.0

C

13

17

22

24

27

20

20

23

D

1/4

6.35

9.52

12.70

15.88

Thickness

(mm)

0.8

0.8

0.8

1.0

3/8

1/2

5/8

[Unit: mm]

45

˚ ~ 46

˚

43

˚ ~ 45

˚

B

C

D

A

(2) Flare Connecting Procedures and Precautions

a) Make sure that the flare and union portions do not have any scar or dust, etc.
b) Correctly align the processed flare surface with the union axis.
c) Tighten the flare with designated torque by means of a torque wrench. The tightening torque for

R410A is same as that for conventional R22. Incidentally, when the torque is wekd, the gas leakage
may occur. When it is strong, the flare nut may crack and may be made nonremovable. When
choosing the tightening torque, comply with values designated by manufacturers. Table 9 shows
reference values.
Note:When applying oil to the flare surface, be sure to use oil designated by the manufacturer. If any
other oil is used, the lubricating oils may deteriorate and cause the compressor to burn out.

Norminal 

diameter

Norminal 

diameter

(mm)

16 (160), 18 (180)

42 (420)

55 (550)

65 (650)

1/4

6.35

9.52

12.70

15.88

14 ~ 18 (140 ~ 180)

33 ~ 42 (330 ~ 420)

50 ~ 62 (500 ~ 620)

63 ~ 77 (630 ~ 770)

3/8

1/2

5/8

Tightening torque

N m (kgf cm)

Tightening torque of torque 

wrenches available on the market

N m (kgf cm)

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.