7. HOW TO PROCESS TUBING. Argo ADS Series, ASS106MH, ADPS140MH, FC22MHG, ASS73MH, SD45MHG, ACS36MH, SD64MHG, ADPS106MH

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7. HOW TO PROCESS TUBING

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

7-1. Connecting the Refrigerant Tubing

Use of the Flaring Method

Many of conventional split system air conditioners employ the flaring method to connect refrigerant tubes which 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 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 be sure to 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

Before

Deburring

After

Fig. 7-1

Copper tubing

Reamer

Fig. 7-2

Flare tool

Fig. 7-3

Flare nut

Copper tubing

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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 to the matching surfaces of the flare and union before connecting them together. This is effective for reducing gas leaks. (Fig. 7-4)

(3) 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. 7-5)

● Adjust the shape of the narrow tube (liquid tube) using a tube bender at the installation site and connect it to the narrow tubing side (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.

7-2. Connecting Tubing Between Indoor and Outdoor Units

(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 as at right:

● When removing the flare nuts from the tubing connections, or when tightening them after connecting the tubing, be sure to use 2 monkey wrenches or spanners as shown. (Fig. 7-6)

If the flare nuts are over-tightened, the flare may be damaged, which could result refrigerant leakage and cause in injury or asphyxiation to room occupants.

● For the flare nuts at tubing connections, be sure to use the flare nuts that were supplied with the unit, or else flare nuts for R410A (type 2). The refrigerant tubing that is used must be of the correct wall thickness as shown in the table at right.

Indoor unit

Apply refrigerant lubricant here and here

Fig. 7-4

Union Flare nut

Fig. 7-5

Torque wrench

Spanner

Outdoor unit

Fig. 7-6

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Tube diameter

φ

6.35 (1/4")

φ

9.52 (3/8")

φ

12.7 (1/2")

φ

15.88 (5/8")

φ

19.05 (3/4")

Tightening torque, approximate

14 – 18 N · m

(140 – 180 kgf · cm)

34 – 42 N · m

(340 – 420 kgf · cm)

49 – 61 N · m

(490 – 610 kgf · cm)

68 – 82 N · m

(680 – 820 kgf · cm)

100 – 120 N · m

(1000 – 1200 kgf · cm)

Tube thickness

0.8 mm

0.8 mm

0.8 mm

1.0 mm

1.0 mm

Because the pressure is approximately 1.6 times higher than conventional refrigerant pressure, the use of ordinary flare nuts (type 1) or thin-walled tubes may result in tube rupture, injury, or asphyxiation caused by refrigerant leakage.

● In order to prevent damage to the flare caused by over-tightening of the flare nuts, use the table above as a guide when tightening.

● When tightening the flare nut on the narrow tube, use a monkey wrench with a nominal handle length of 200 mm.

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7-3. Insulating the Refrigerant Tubing

Tubing Insulation

● Thermal insulation must be applied to all unit tubing, including distribution joint (purchased separately).

* For gas tubing, the insulation material must be heat resistant to 120°C or above. For other tubing, it must be heat resistant to 80°C or above.

Insulation material thickness must be 10 mm or greater.

If the conditions inside the ceiling exceed DB 30°C and RH 70%, increase the thickness of the gas tubing insulation material by 1 step.

CAUTION

If the exterior of the outdoor unit valves has been finished with a square duct covering, make sure you allow sufficient space to use the valves and to allow the panels to be attached and removed.

Taping the flare nuts

Wind the white insulation tape around the flare nuts at the wide tube connections. Then cover up the tubing connections with the flare insulator, and fill the gap at the union with the supplied black insulation tape.

Finally, fasten the insulator at both ends with the supplied vinyl clamps. (Fig. 7-8)

Insulation material

The material used for insulation must have good insulation characteristics, be easy to use, be age resistant, and must not easily absorb moisture.

CAUTION

After a tube has been insulated, never try to bend it into a narrow curve because it can cause the tube to break or crack.

Two tubes arranged together

Narrow tubing

Insulation

Three tubes arranged together

Cosmetic

(finishing) tape

Narrow tubing

Wide tubing

Insulation

Fig. 7-7

Wide tubing

Balance tubing

Sealer (supplied)

Insulation tape (white)

(supplied)

Flare insulator (supplied)

Unit side insulator

Tube insulator

(not supplied)

Heat resistant

120

°

C or above

Flare nut

Vinyl clamps (supplied)

Fig. 7-8

Drain insulator and clamp.

Large

(supplied)

Refrigerant tubing and insulator

(not supplied)

Drain pipe and insulator

(not supplied)

Packing clamp.

Small hose band

(supplied)

Seal

Insulation tape

Vinyl

Flare insulator clamp

The procedure used for installing the insulator for both wide and narrow tubes is the same.

Fig. 7-9

Never grasp the drain or refrigerant connecting outlets when moving the unit.

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7-4. Taping the Tubes

(1) At this time, the refrigerant tubes (and electrical wiring if local codes permit) should be taped together with armoring tape in 1 bundle. To prevent the condensation from overflowing the drain pan, keep the drain hose separate from the refrigerant tubing.

(2) Wrap the armoring tape from the bottom of the outdoor unit to the top of the tubing where it enters the wall. As you wrap the tubing, overlap half of each previous tape turn.

(3) Clamp the tubing bundle to the wall, using 1 clamp approx. each meter. (Fig. 7-10)

NOTE

Do not wind the armoring tape too tightly since this will decrease the heat insulation effect. Also ensure that the condensation drain hose splits away from the bundle and drips clear of the unit and the tubing.

7-5. Finishing the Installation

After finishing insulating and taping over the tubing, use sealing putty to seal off the hole in the wall to prevent rain and draft from entering. (Fig. 7-11)

Clamp

Insulated tubes Drain hose

Fig. 7-10

Apply putty here

Tubing

Fig. 7-11

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