How to Process Tubing, Use of the Flaring Method

7. How to Process Tubing

The narrow tubing side is connected by flare nut, and the wide tubing side is connected by brazing.

7-1. 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.

7-2. Flaring Procedure with a Flare Tool

(1)Cut the copper tube to the required length with a tube cutter. It is recommended to cut about

12 – 20 in. longer than the estimated tubing length.

(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. 7-1)

NOTE

When reaming, hold the tube end downward and be sure that no copper scraps fall into the tube. (Fig. 7-2)

(3)Remove the flare nut from the unit and mount it on the copper tube.

(4)Make a flare at the end of copper tube with a flare

tool.* (Fig. 7-3)

*Use “RIGID®” or equivalent.

NOTE

A good flare should have the following characteristics:

●inside surface is glossy and smooth.

●edge is smooth.

●tapered sides are of uniform length.

7-3. Precaution before Connecting Tubes Tightly

(1)Apply a sealing cap or water-proof tape to pre- vent dust or water from entering the tubes before they are used.

(2)Apply refrigerant lubricant to the matching sur- faces of the flare and union before connecting them together. This helps to reduce gas leaks. (Fig. 7-4)

(3)For proper connection, align the union tube and flare tube with each other, then screw in the flare nut lightly at first to obtain a smooth match.

(Fig. 7-5)

●Adjust the shape of the narrow and wide tubes using a tube bender at the installation site and connect them to the each tubing side valve using a flare nut.

Deburring

Before		After

Fig. 7-1

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Copper tubing

Reamer

0127_M_I

Fig. 7-2

Flare nut

Copper tubing

Flare tool

0128_M_I

Fig. 7-3

Apply refrigerant lubricant here and here

0129_M_I

Fig. 7-4

Union	Flare nut
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Fig. 7-5

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