Technical Data Manual

ManualsBrandsPanasonic ManualsHeating & Air ConditioningPanasonic Mini ECO-i

Design of Mini VRF SYSTEM

2 - 39

5. HOW TO PROCESS TUBING

lubricant

Caution Before Connecting Tubes Tightly

(1)

(2)

(3)

Apply a sealing cap or water-proof tape to prevent dust or

water from entering the tubes before they are used.

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.2-18)

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.2-19)

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 dam-

aged. 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.

5-2. Connecting Tubing Between Indoor and Outdoor

Units

(1)

(2)

Tightly connect the indoor-side refrigerant tubing

extended from the wall with the outdoor-side tubing.

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 adjustable wrenches or

spanners as shown. (Fig. 2-20)

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.

Apply refrigerant

Fig. 2-18

Flare nut

Union

Fig. 2-19

Fig. 2-20

Indoor unit

Outdoor unit

Spanner

Torque wrench

Tube diameter

ø1/4"

(ø6.35 mm)

ø3/8"

(ø9.52 mm)

ø1/2"

(ø12.7 mm)

ø5/8"

(ø15.88 mm)

ø3/4"

(ø19.05 mm)

Tightening torque,

approximate

120 – 160 lbs

in.

(140 – 180 kgf

cm)

300 – 360 lbs

in.

(340 – 420 kgf

cm)

430 – 480 lbs

in.

(490 – 550 kgf

cm)

590 – 710 lbs

in.

(680 – 820 kgf

cm)

870 – 1040 lbs

in.

(1000 – 1200 kgf

cm)

1/32"

(0.8 mm)

1/32"

(0.8 mm)

5/128"

(1.0 mm)

over 5/128"

(1.0 mm)

Tube thickness

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 liquid tube,

use an adjustable wrench with a nominal handle

length of 7-7/8".

TD831156-00_MINI_VRF_SYS.indb 39TD831156-00_MINI_VRF_SYS.indb 39 2012/01/31 14:38:502012/01/31 14:38:50