Toshiba RAV-SM304SDT-E Installation Manual Download Page 14

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Refrigerant piping



Refrigerant piping

If the outdoor units are to be mounted on a wall,
make sure that the supporting platform is
sufficiently strong. The platform should be
designed and manufactured to maintain its strength
over a long period of time, and sufficient
consideration should be given to ensuring that the
outdoor unit will not fall.

Use copper pipe with 0.8 mm or more thickness.

Flare nut and flare works are also different from
those of the conventional refrigerant.
Take out the flare nut attached to the main unit of
the air conditioner, and use it.

REQUIREMENT

When the refrigerant pipe is long, provide support brackets
at intervals of 2.5 to 3m to clamp the refrigerant pipe.
Otherwise, abnormal sound may be generated.

CAUTION

IMPORTANT 4 POINTS FOR PIPING WORK

1. Remove dust and moisture from the inside of the

connecting pipes.

2. Tight connection (between pipes and unit)
3. Evacuate the air in the connecting pipes using VACUUM

PUMP.

4. Check the gas leakage. (Connected points)



Pipe size



Permissible piping length and
height difference

They vary according to the outdoor unit.
For details, refer to the Installation Manual attached to the
outdoor unit.

◆

Flaring

▼

Projection margin in flaring : B (Unit : mm)

Rigid (Clutch type)

▼

Flaring dia. meter size : A (Unit : mm)

RAV-SM

Pipe size(mm)

Liquid side

Gas side

SM30

Ø6.4

Ø9.5

SM40, 45, 56

Ø6.4

Ø12.7

• Cut the pipe with a pipe cutter.

Remove burrs completely.
Remaining burrs may cause gas leakage.

• Insert a flare nut into the pipe,

and flare the pipe.
As the flaring sizes of R410A
differ from those of refrigerant
R22, the flare tools newly
manufactured for R410A are
recommended.
However, the conventional
tools can be used by adjusting
projection margin of the
copper pipe.

Outer dia. of

copper pipe

R410A tool used

Conventional

tool used

R410A

6.4 , 9.5

0 to 0.5

1.5 to 2.0

12.7

Outer diam. of copper pipe

R410A

6.4

9.1

9.5

13.2

12.7

16.6

* In case of flaring for R410A with the

conventional flare tool, pull it out approx.
0.5 mm more than that for R22 to adjust to
the specified flare size.
The copper pipe gauge is useful for
adjusting projection margin size.

+0
–0.4

Tightening connection

CAUTION

Do not apply excessive torque. Otherwise, the nut may
crack depending on the conditions.

▼

Tightening torque of flare pipe connections

REQUIREMENT

Tightening with an excessive torque may crack the nut
depending on installation conditions.
Tighten the nut within the specified tightening torque.

◆

Piping with outdoor unit

Shape of valve differs according to the outdoor unit.
For details of installation, refer to the Installation Manual of
the outdoor unit.



Air purge

Using a vacuum pump, perform vacuuming from the charge
port of valve of the outdoor unit.
For details, follow to the Installation Manual attached to the
outdoor unit.
• Never use the refrigerant sealed in the outdoor unit for air

purge.

REQUIREMENT

For the tools such as charge hose, etc., use those
manufactured exclusively for R410A.

◆

Refrigerant amount to be added

For addition of the refrigerant, add refrigerant “R410A”
referring to the attached Installation Manual of outdoor unit.
Be sure to use a scale to charge the refrigerant of specified
amount.

REQUIREMENT

• Charging an excessive or too little amount of refrigerant

causes of the compressor.
Be sure to charge the refrigerant of specified amount.

• A personnel who charged the refrigerant should write

down the pipe length and the added refrigerant amount in
the nameplate attached to the service panel of the
outdoor unit. It is necessary to troubleshoot the
compressor and refrigeration cycle malfunction.

◆

Open the valve fully

Open the valve of the outdoor unit fully. A 4 mm-hexagonal
wrench is required for opening the valve.
For details, refer to the Installation Manual attached to the
outdoor unit.

(Unit : N•m)

Outer dia. of copper pipe

Tightening torque

6.4 mm (dia.)

14 to 18 (1.4 to 1.8 kgf•m)

9.5 mm (dia.)

34 to 42 (3.4 to 4.2 kgf•m)

12.7 mm (dia.)

49 to 61 (4.9 to 6.1 kgf•m)

Pressure of R410A is higher
than that of R22.
(Approx. 1.6 times)
Therefore, using a torque
wrench, tighten the flare pipe
connecting sections which
connect the indoor and
outdoor units of the specified
tightening torque.
Incorrect connections may
cause not only a gas leak,
but also of the refrigeration
cycle.
Align the centres of the
connecting pipes and tighten
the flare nut as far as
possible with your fingers.
Then tighten the nut with a
spanner and torque wrench
as shown in the figure.