Panasonic Inverter R32 Series Technical Data & Service Manual page 189

1
HOW TO PROCESS TUBING
Must ensure mechanical connections be accessible for
maintenance purposes.
Connecting the Refrigerant Tubing
NOTE
When connecting flare at indoor side, make sure that the flare
connection is used only once. If torqued up and released, the
flare must be remade. Once the flare connection was torqued
up correctly and leak test was made, thoroughly clean and
dry the surface to remove oil, dirt and grease by following
instructions of silicone sealant. Apply neutral cure & ammonia-
free silicone sealant that is non-corrosive to copper & brass to
the external of the flared connection to prevent the ingress of
moisture on both the gas & liquid sides. (Moisture may cause
freezing and premature failure of the connection.)
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
NOTE
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.
NOTE
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
After
Copper
tubing
Reamer
Flare nut
Copper
tubing
Flare tool
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.
(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.
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.
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 flare nuts, apply specified torque.
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.
Torque wrench
Indoor unit
1-11-88
Apply refrigerant lubricant.
Flare nut
Union
60 71 100 125 140
ø15.88
ø9.52
Spanner
Outdoor unit