Panasonic S-200PE1E8, Technical Data & Service Manual

Page: 74 / 197

1-68
1 1
1-11. HOW TO PROCESS TUBING
The liquid tubing side is connected by a flare nut, and the gas tubing side is connected by brazing.
1. Connecting the Refrigerant Tubing
Use of the Flaring Method
Many of conventional split system air conditioners employ the flaring method to connect refrigerant tubes that run
between indoor and outdoor units.
In this method, the copper tubes are flared at each end and connected with flare 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 file. This process is important and should
be done carefully to make a good flare. Be sure to keep
any contaminants (moisture, dirt, metal filings, etc.) from
entering the tubing. (Figs. 1- 40 and 1- 41)
When reaming, hold the tube end downward and be sure that
no copper scraps fall into the tube. (Fig. 1- 41)
(3) Remove the flare nut from the unit and be sure to mount it
on the copper tube.
After Before
Deburring
Copper
tubing
Reamer
Fig. 1- 40
Fig. 1- 41
Fig. 1- 42
NOTE
NOTE
(4) Make a flare at the end of the copper tube with a flare tool.
(Fig. 1- 42)
A good flare should have the following characteristics:
inside surface is glossy and smooth
edge is smooth
tapered sides are of uniform length
Flare size: A (mm)
A
Copper tubing
(Outer dia.)
A
0
– 0.4
ø6.35
ø9.52
ø12.7
ø15.88
ø19.05 9.1
13.2
16.6
19.7
24.0
Flare nut
Copper
tubing
Flare tool
<Type E2>
(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 flare nut before making piping connections.
This is effective for reducing gas leaks. (Fig. 1- 43)
(3) For proper connection, align the union tube and flare tube
straight with each other, then screw on the flare nut lightly
at first to obtain a smooth match. (Fig. 1- 44)
(1) Tightly connect the indoor-side refrigerant tubing extended
from the wall with the outdoor-side tubing.
Because the pressure is approximately 1.6 times higher than
conventional refrigerant pressure, the use of ordinary flare
nuts (Type 1) or thin-walled tubes may result in tube rupture,
injury, or asphyxiation caused by refrigerant leakage.
(2) To fasten the flare nuts, apply specified torque.
Caution Before Connecting Tubes Tightly
Cautions During Brazing
Apply refrigerant lubricant.
Fig. 1- 43
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 flare.
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.)
Use a reducing valve for the nitrogen cylinder.
When removing the flare nuts from the tubing connections,
or when tightening them after connecting the tubing, be sure
to use 2 adjustable wrenches or spanners. (Fig. 1- 45)
If the flare nuts are over-tightened, the flare may be damaged,
which could result in refrigerant leakage and cause injury or
asphyxiation to room occupants.
For the flare nuts at tubing connections, be sure to use the
flare nuts that were supplied with the unit, or else flare nuts
for R410A (Type 2). The refrigerant tubing that is used must
be of the correct wall thickness as shown in the table.
In order to prevent damage to the flare caused by
overtightening of the flare nuts, use the table as a guide
when tightening.
When tightening the flare nut on the liquid tube, use an
adjustable wrench with a nominal handle length of 200 mm.
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.
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.
2. Connecting Tubing Between Indoor and Outdoor Units
Indoor Unit Tubing Connection (
1
,
2
...
n-1
)
Indoor unit type
Gas tubing (mm)
Liquid tubing (mm)
200
ø25.4
ø9.52
250
ø25.4
ø12.7
Outdoor unit
Torque wrench
Spanner
Indoor unit
Fig. 1- 45
Tightening torque
(approximate)
14 – 18 N · m
{140 – 180 kgf · cm}
34 – 42 N · m
{340 – 420 kgf · cm}
49 – 61 N · m
{490 – 610 kgf · cm}
68 – 82 N · m
{680 – 820 kgf · cm}
Tube
diameter
ø6.35 (1/4")
ø9.52 (3/8")
ø12.7 (1/2")
ø15.88 (5/8")
ø19.05 (3/4")
100 – 120 N · m
{1000 – 1200 kgf · cm}
Tube
thickness
0.8 mm
0.8 mm
0.8 mm
1.0 mm
1.0 mm
Flare nut
Union
Fig. 1- 44
Sec1.indd 68 2014/11/07 10:28:09