Panasonic S-160PE1R5B Technical Data & Service Manual page 113

HOW TO PROCESS TUBING
Must ensure mechanical connections be accessible for maintenance
purposes.
The liquid tubing side is connected by a flare nut, and the gas tubing
side is connected by brazing.
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 a similar tool.
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.
Deburring
Before After
N OTE
When reaming, hold the tube end downward and be sure that no copper
scraps fall into the tube.
(3) Remove the flare nut from the unit and be sure to mount it on the
copper tube.
(4) Make a flare at the end of the copper tube with a flare tool.
Flare nut
Copper
tubing
Flare tool
N OTE
When flared joints are reused, the flare part shall be re-fabricated.
A good flare 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 flare nut before making piping connections.
This is effective for reducing gas leaks.
Apply refrigerant lubricant.
(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.
Flare nut
Union
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.
Cautions During Brazing
Connecting Tubing Between Indoor and Outdoor Units
(1) Tightly connect the indoor-side refrigerant tubing extended from
(2) To fasten the flare nuts, apply specified torque.
Copper
tubing
Reamer
Insulating the Refrigerant Tubing
Tubing Insulation
Must ensure that pipe-work shall be protected from physical damage.
1-11-2-2-11
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, causing 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.
the wall with the outdoor-side tubing.
Indoor Unit Tubing Connection
Indoor unit type 180
ø19.05 (~ 50 m)
Gas tubing (mm)
ø25.4 (Over 50 ~ 75 m) ø25.4 (Over 30 ~ 60 m)
Liquid tubing (mm) ø9.52
When removing the flare nuts from thetubing connections, or
when tightening them after connecting the tubing, be sure to
use a torque wrench and a spanner.
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.
Torque wrench
Spanner
Indoor unit
Outdoor unit
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,
R32 (type 2). The refrigerant tubing that is used must be of the
correct wall thickness as shown in the table below.
Tightening torque
Tube diameter Tube thickness
(approximate)
34 – 42 N · m
ø9.52 (3/8")
{340 – 420 kgf · cm}
49 – 55 N · m
ø12.7 (1/2")
{490 – 550 kgf · cm}
Because the pressure is approximately 1.6 times higher than
conventional refrigerant R22 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.
In order to prevent damage to the flare caused by over-tightening
of the flare nuts, use the table above 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.
Thermal insulation must be applied to all units tubing, including
distribution joint (field supply).
* For gas tubing, the insulation material must be heat resistant
to 120°C or above. For other tubing, it must be heat resistant
to 80°C or above.
Insulation material thickness must be 10 mm or greater.
If the conditions inside the ceiling exceed DB 30°C and RH 70%,
increase the thickness of the gas tubing insulation material by 1 step.
200 / 224
ø19.05 (~ 30 m)
ø12.7
0.8 mm
0.8 mm
1