Panasonic S-73MK2E5A - 5 How to Process Tubing; Connecting the Refrigerant Tubing; Connecting Tubing between Indoor and Outdoor Units

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5. HOW TO PROCESS TUBING
5-1. 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 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.
AfterBefore
Deburring
Copper
tubing
Reamer
N OT E
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 OT E
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.
5-2. Connecting Tubing Between Indoor and
Outdoor Units
N OT E
When connecting to the mini VRF 8HP, 10HP (outdoor unit),
select the main tube by using the following values. For details,
refer to the installation instructions of the outdoor unit.
Indoor unit 45 56 73 106
Type K2 0.152 0.188
(1) Tightly connect the indoor-side refrigerant tubing extended
from the wall with the outdoor-side tubing.
(2) To fasten the flare nuts, apply specified torque.
Indoor Unit Tubing Connection (
1
,
2
...
n-1
)
Indoor unit type 45 56 73 106
Gas tubing (mm) ø12.7 ø15.88
Liquid tubing (mm) ø6.35 ø9.52
● When removing the flare nuts from the tubing 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.
Outdoor unit
Torque wrench
Spanner
Indoor unit
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