How To Process Tubing - Panasonic S-36PN1E5 Installation Instructions Manual

5. HOW TO PROCESS TUBING

The liquid tubing side is connected by a flare nut, and the gas
tubing side is connected by brazing.
5-1. 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 fi le. This process is important and should be
done carefully to make a good fl are. Be sure to keep any
contaminants (moisture, dirt, metal fi lings, etc.) from entering
the tubing. (Figs. 5-1 and 5-2)
Deburring
Before After
Fig. 5-1
NOTE
When reaming, hold the tube end downward and be sure that no
copper scraps fall into the tube. (Fig. 5-2)
(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. 5-3)
Flare tool
NOTE
A good fl are should have the following characteristics:
O
inside surface is glossy and smooth
O
edge is smooth
O
tapered sides are of uniform length
Copper
tubing
Reamer
Fig. 5-2
Flare nut
Copper
tubing
Fig. 5-3
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. 5-4)
Apply refrigerant lubricant.
(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. 5-5)
O
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
O
Replace air inside the tube with nitrogen gas to prevent
copper oxide lm from forming during the brazing
process. (Oxygen, carbon dioxide and Freon are not
acceptable.)
O
Do not allow the tubing to get too hot during brazing.
The nitrogen gas inside the tubing may overheat, causing
refrigerant system valves to become damaged. Therefore
allow the tubing to cool when brazing.
O
Use a reducing valve for the nitrogen cylinder.
O
Do not use agents intended to prevent the formation
of oxide lm. These agents adversely affect the
refrigerant and refrigerant oil, and may cause damage or
malfunctions.
5-2. 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 (
Indoor unit type
Gas tubing (mm)
Liquid tubing (mm)
(2) To fasten the fl are nuts, apply specifi ed torque.
O
When removing the fl are nuts from the tubing connections, or
when tightening them after connecting the tubing, be sure to
use 2 adjustable wrenches or spanners. (Fig. 5-6)
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.
Indoor unit
22
Flare nut
Union
)
1, 2... n-1
60 71 100 125 140
ø15.88
ø9.52
Torque wrench
Spanner
Outdoor unit
Fig. 5-4
Fig. 5-5
Fig.5-6