1
1-11-75
Must ensure mechanical connections be accessible for
maintenance purposes.
Connecting the Refrigerant Tubing
Use of the Flaring Method
Many of conventional split system air conditioners employ the
fl aring method to connect refrigerant tubes that run between
indoor and outdoor units. In this method, the copper tubes are
fl ared at each end and connected with fl are nuts.
Flaring Procedure with a Flare Tool
(1) Cut the copper tube to the required length with a tube cutter.
It is recommended to cut approx. 30 – 50 cm longer than the
tubing length you estimate.
(2) Remove burrs at each end of the copper tubing with a tube
reamer or a smilar tool. This process is important and should
be done carefully to make a good flare. Be sure to keep any
contaminants (moisture, dirt, metal fi lings, etc.) from entering
the tubing. (Figs. 1-11-34 and 1-11-35)
Deburring
Before After
Copper
tubing
Reamer
Fig. 1-11-34 Fig. 1-11-35
NOTE
When reaming, hold the tube end downward and be sure
that no copper scraps fall into the tube. (Fig. 1-11-35)
(3) Remove the fl are nut from the unit and be sure to mount it on
the copper tube.
(4) Make a fl are at the end of the copper tube with a fl are tool.
(Fig. 1-11-36)
Flare nut
Copper
tubing
Flare tool
Fig. 1-11-36
NOTE
When fl ared joints are reused, the fl are part shall be re-fabricated.
A good fl are should have the following characteristics:
inside surface is glossy and smooth
edge is smooth
tapered sides are of uniform length
Caution Before Connecting Tubes Tightly
(1) Apply a sealing cap or water-proof tape to prevent dust or
water from entering the tubes before they are used.
(2) Be sure to apply refrigerant lubricant (ether oil) to the inside
of the fl are nut before making piping connections. This is
effective for reducing gas leaks. (Fig. 1-11-37)
Apply refrigerant lubricant. Don’t use any kind of leak lock or leak
sealants on any flare connection as this may cause system blockages.
Fig. 1-11-37
(3) For proper connection, align the union tube and fl are tube
straight with each other, then screw on the fl are nut lightly at
fi rst to obtain a smooth match. (Fig. 1-11-38)
Union
Flare nut
Fig. 1-11-38
Adjust the shape of the liquid tube using a tube bender at the installation
site and connect it to the liquid tubing side valve using a fl are.
Cautions During Brazing
Replace air inside the tube with nitrogen gas to prevent
copper oxide film from forming during the brazing process.
(Oxygen, carbon dioxide and Freon are not acceptable.)
Do not allow the tubing to get too hot during brazing.
The nitrogen gas inside the tubing may overheat, caus-
ing refrigerant system valves to become damaged.
Therefore allow the tubing to cool when brazing.
Use a reducing valve for the nitrogen cylinder.
Do not use agents intended to prevent the formation of
oxide film. These agents adversely affect the refrigerant and
refrigerant oil, and may cause damage or malfunctions.
Connecting Tubing Between Indoor and Outdoor Units
(1) Tightly connect the indoor-side refrigerant tubing extended
from the wall with the outdoor-side tubing.
Indoor Unit Tubing Connection ( 1, 2... n-1)
Indoor unit type 60 71 100 125 140
Gas tubing (mm) ø15.88
Liquid tubing (mm) ø9.52
Min. tubing length (m)
(R32 series)
53
(2) To fasten the fl are nuts, apply specifi ed torque.
When removing the fl are nuts from the tubing connections, or
when tightening them after connecting the tubing, be sure to
use a torque wrench and spanner. (Fig. 1-11-39)
If the fl are nuts are over-tightened, the fl are may be
damaged, which could result in refrigerant leakage and cause
injury or asphyxiation to room occupants.
Torque wrench
Fig.1-11-39
Spanner
Indoor unit
Outdoor unit
HOW TO PROCESS TUBING
SM830266-00_大洋州向けR32シングルTD&SM.indb 75 18/03/29 10:20:59
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