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2. Installing the indoor unit
90°
B
A
A Fresh air intake hole (Knock out)
B 4-ø2.8 burring hole
Fig. 2-9
3. Installing the refrigerant piping
A
45°±2°
Apply refrigerating machine oil over the entire flare seat surface.
Be sure to only use the flare nuts that came with the unit.
Fig. 3-1
A Flare cutting dimensions
Copper pipe O.D.
Flare dimensions
(mm)
øA dimensions (mm)
ø6.35
ø9.52
12.6 - 13.0
ø12.7
15.8 - 16.2
ø15.88
19.0 - 19.4
ø19.05
22.9 - 23.3
B Flare nut tightening torque
Copper pipe O.D.
Tightening torque
(mm)
ø6.35
ø9.52
ø12.7
ø15.88
ø19.05
250
288.5
A
B
8.6 - 9.0
Tightening angle
(N·m)
(Guideline)
14 - 18
60˚ - 90˚
35 - 42
60˚ - 90˚
50 - 58
30˚ - 60˚
75 - 80
30˚ - 60˚
100 - 140
20˚ - 35˚
(mm)
2.5. Fresh air intake hole (Fig. 2-9)
At the time of installation, use the hole (knock out) located at the positions shown in
following diagram, as and when required.
Note:
Make sure that the fresh air intake is no more than 20% of the entire air intake
(when the air flow speed is set to its highest setting).
Caution:
Linkage of duct fan and air conditioner.
If a duct fan is used, be sure to link it with the air conditioner when outside air
is taken in.
Do not run just the duct fan. Otherwise, condensation may form.
3.1. Precautions for devices that use R407C refrigerant
• Do not use the existing refrigerant piping.
• Do not use crushed, misshapen, or discolored tubing. The inside of the tub-
ing should be clean and free from harmful sulfuric compounds, oxidants,
dirt, debris, oils and moisture.
• Store the piping to be used during installation indoors and keep both ends of
the piping sealed until just before brazing.
• Use ester oil, ether oil or alkylbenzene (small amount) as the refrigerator oil
to coat flares and flange connections.
• Use liquid refrigerant to fill the system.
• Do not use a refrigerant other than R407C.
• Use a vacuum pump with a reverse flow check valve.
• Do not use the tools that are used with conventional refrigerants.
• Do not use a charging cylinder.
• Be especially careful when managing the tools.
• Do not use commercially available dryers.
3.2. Indoor unit (Fig. 3-1)
• When commercially available copper pipes are used, wrap liquid and gas pipes
with commercially available insulation materials (heat-resistant to 100 °C or more,
thickness of 12 mm or more).
• The indoor parts of the drain pipe should be wrapped with polyethylene foam insu-
lation materials (specific gravity of 0.03, thickness of 9 mm or more).
• Apply thin layer of refrigerant oil to pipe and joint seating surface before tightening
flare nut.
• Use two wrenches to tighten piping connections.
• Use leak detector or soapy water to check for gas leaks after connections are
completed.
• Use refrigerant piping insulation provided to insulate indoor unit connections. Insu-
late carefully following shown below.
Refrigerant and Drainage Piping Sizes
Model
Item
Liquid
Refrigerant
piping
Gas
Drainage piping
25
35, 50
O.D. ø6.35 (1/4")
O.D. ø9.52 (3/8")
O.D. ø12.7 (1/2")
O.D. ø15.88 (5/8")
PVC pipe: O.D. ø26 (1")
5
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