How To Process Tubing; Connecting The Refrigerant Tubing - Panasonic S-140MH1H5 Installation Instructions Manual

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 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. 5-1 and 5-2)
N OT E
When reaming, hold the tube end downward and be sure that no copper scraps
fall into the tube. (Fig. 5-2)
(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. (Fig. 5-3)
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. (Fig. 5-4)
(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. 5-5)
•
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
• 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.
Deburring
Before
Apply refrigerant lubricant.
20
After
Fig. 5-2
Fig. 5-1
Flare nut
Flare tool
Fig. 5-3
Fig. 5-4
Flare nut
Union
Fig. 5-5
Copper
tubing
Reamer
Copper
tubing