16
5. Refrigerant Tubing
5-1. Use of the Flaring Method
Many of the conventional split system air conditioners
employ the flaring method to connect refrigerant tubes
which run between indoor and outdoor units. In this
method, the copper tubes are flared at each end and
connected with flare nuts.
5-2. 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. 12" to
20" (30 to 50 cm) longer than the tubing length you
estimate.
(2) Remove burrs at the end of the copper tube with a
tube reamer or file. This process is important and
should be done carefully to make a good flare.
(Fig. 15)
When reaming, hold the tube end downward and be
sure that no copper scraps fall into the tube. (Fig. 16)
(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 copper tube with a flare
tool.*(Figs. 17 and 18)
(*Use “RIDGID” or equivalent.)
A good flare should have the following characteristics:
inside surface is glossy and smooth.
edge is smooth.
tapered sides are of uniform length.
5-3. Caution before Connecting Tubes Tightly
a) Be sure to apply a sealing cap or water-proof tape
to prevent dust or water from getting into the tubes
before they are used.
b) Be sure to apply refrigerant lubricant to the match-
ing surfaces of the flare and union before connect-
ing them together. This is effective for reducing gas
leaks. (Fig. 19)
c) For proper connection, align the union tube and
flare tube straight with each other, then screw in the
flare nut lightly at first to obtain a smooth match.
(Fig. 20)
NOTE
NOTE
Fig. 15
Deburring
Before After
Fig. 16
Reamer
Copper
tubing
Fig. 17
0 to 0.0196"
(0 to 0.5 mm)
If the special R410A
flare tool is used:
0.0472" (1.2 mm)
If the previous flare tool
(clutch-type) is used:
Adjust so that the amount of tube
protrusion is as shown in the figure.
Fig. 18
Flare tool
Flare nut
Copper
tubing
Fig. 19
Apply refrigerant
lubricant here and here
Fig. 20
Flare nut
Union