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6. Mounting the Branch Box

(1) Install the suspension bolts (procure locally) at the speci

ed pitch (Fig. 4-2, 4-3).

(2) Fit the washers and nuts (

, procure locally) to the suspension bolts.

(Fig. 6-1)
(3) Hang the unit on the suspension bolts.
(4) Fully tighten the nuts (check ceiling height).
(5) Use a level to adjust the branch box to the horizontal.

When unit is hung and nuts tightened

Suspension bolt

Nut

Washer (with cushion)

Ensure that cushion faces downwards

Washer (without cushion)

Nut (procure locally)

Ceiling board

7. Installing refrigerant piping

(

)

Bracket

Cool them with wet
towels and so on.

►

Connect the liquid and gas pipes of each indoor unit to the same end

connection numbers as indicated on the indoor unit flare connection
section of each Branch Box. If connected to wrong end connection
numbers, it doesn’t work normally.

►

When connecting indoor units, make sure to connect refrigerant pipes

and connection wires to the appropriate connection ports marked with
matching alphabets. (Ex. A, B, C, D, E)

Note:
Be sure to mark all the local refrigerant piping (liquid pipes, gas pipes, etc.)
for each indoor unit designating clearly which room it belongs in. (Ex. A, B,
C, D, E)

►

List indoor unit model names in the name plate on the control box of

Branch Box (for identification purposes).

• Conduct suf

cient anti-condensation and insulation work to prevent water drip-

ping from the refrigerant piping. (liquid pipe/gas pipe)

• Increase insulation depending on the environment where the refrigerant piping is

installed, or condensation may occur on the surface of the insulation material.
(Insulation material Heat-resistant temperature: 120 °C, Thickness:
15 mm or more)

* When the refrigerant piping is used in locations subject to high temperature

and humidity such as in the attic, further addition of insulation may be re-
quired.

• To insulate the refrigerant piping, apply heat-resistant polyethylene foam be-

tween the indoor unit and insulation material as well as to the net between the
insulation material

lling all gaps.

(Condensation forming on the piping may result in condensation in the room or
burns when contacting the piping.)

►

When using commercially available refrigerant piping, ensure that both

liquid and gas piping are wrapped with commercially available thermal
insulation materials (insulation materials at least 12 mm thick and able
to withstand temperatures in excess of 100 ºC).

►

Refer to the installation manual of the outdoor unit when creating a

vacuum and opening or closing valves.

When connecting piping by brazing, be sure to use nitrogen-substituted non-
oxidation brazing. Do not use commercial antioxidants which may cause pipe
corrosion and degradation of refrigerator oil. Use non-oxidation brazing, or the
compressor may be damaged. (Fig. 7-2)
*1 Properly ventilate during brazing work. Before brazing in a closed room or a

small room, make sure that there is no refrigerant leakage. Buildup of leaked
refrigerant poses toxicity and combustion issues.

*2 Keep ignition sources, such as gas burning appliances and electrical heater,

etc., away from where the air conditioner is being installed or repaired.

*3 Use good quality brazing

ller metal.

*4 When using

ux, pay attention to the following points.

•

After brazing, completely remove flux. If the chlorine contained in the

ux remaining in the pipe, the refrigerator oil is degraded and it becomes

contamination.

Fig. 6-1

(mm)

Fig. 6-2

* Purchase an appropriate

bracket locally if the unit
is to be mounted on a
wall.

Fig. 7-1

CAUTION

• Use refrigerant piping made of phosphorus deoxidized copper and cop-

per alloy seamless pipes and tubes. In addition, be sure that the inner and
outer surfaces of the pipes are clean and free of hazardous sulphur, oxides,
dust/dirt, shaving particles, oils, moisture, or any other contaminant.
– R410A is a high-pressure refrigerant and can cause the existing piping to

burst.

• Store the piping to be used during installation indoors and keep both ends

of the piping sealed until just before brazing. (Store elbows and other joints
in a plastic bag.)
– If dust, dirt, or water enters the refrigerant cycle, deterioration of the oil

and compressor failure may result.

NOTE
• After pipe connection, be sure to check that there is no gas leakage, using

a leak detector or soap-and-water solution.

•

Before brazing the refrigerant piping, always wrap the piping on the main
body, and the thermal insulation piping, with wet towels to prevent heat
shrinkage and burning the thermal insulation tubing. Take care to ensure
that the fl ame does not come into contact with the main body itself. (Fig.7-1)

•

Do not use leak-detection additives.

（

）

Nitrogen gas pressure

0.02MPa or less

Pressure reducing valve (regulator)

to prevent air
from entering.

Note: Do not block the exit side.

When inner pressure
exceeds atmospheric
pressure, pin holes are
created which may cause
leaks from the brazed area.

Place to be brazed

Hand valve