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(2) Pass the connection pipes through the grommets of coil access panel (left) and align
them to the liquid and gas pipes.
(3) Protect the periphery of brazing area by wet cloth, etc. and then braze the pipes.
: Protect these areas with wet cloth, etc.
Connection pipe (liquid)
Connection pipe (gas)
Grommets
Thermistor
Drain ports
Drain pan
Coil access panel (left)
WARNING
Be sure to use wet cloth, etc., to protect the pipe heat insulation and grommets. Because
these parts are extremely flammable, they can cause a fire if they are not properly
protected.
In case the thermistor may be damaged by heat of brazing, which lead to failure of normal
operation.
Do not expose the unit (panel, drain pan, drain port, etc.) to the
fl
ame. The exposure of
these parts to the
fl
ame will adversely affect their appearance and functions or cause a
water leakage.
CAUTION
If air or another type of refrigerant enters the refrigeration cycle, the internal pressure in the
refrigeration cycle will become abnormally high and prevent the unit from exerting its full
performance.
Apply nitrogen gas while
brazing the pipes. Nitrogen gas
pressure:
2.9 psi (0.02 MPa)
(= pressure felt suf
fi
ciently on
the back of your hand)
Pressure regulating valve
Cap
Nitrogen gas
Brazing area
If a pipe is brazed without applying nitrogen gas, it will create an oxidation
fi
lm.
This can degrade performance or damage the parts in the unit (such as the compressor or
valves).
Do not use
fl
ux to braze pipes. If the
fl
ux is the chlorine type, it will cause the pipes to
corrode. Furthermore, if the
fl
ux contains
fl
uoride, it will adversely affect the refrigerant pipe
system such as by degrading the refrigerant oil.
For brazing material, use phosphor copper that does not require
fl
ux.
4.2 Pipe requirement
CAUTION
Refer to the Installation Manual of the outdoor unit for description of the length of
connecting pipe or for difference of its elevation.
• Use pipe with water-resistant heat insulation.
CAUTION
Install heat insulation around both the gas and liquid pipes. Failure to do so may cause
water leaks. Use heat insulation with heat resistance above 248°F (120°C). (Reverse cycle
model only)
In addition, if the humidity level at the installation location of the refrigerant piping is
expected to exceed 70 %, install heat insulation around the refrigerant piping. If the
expected humidity level is 70 to 80 %, use heat insulation that is 9/16 in (15 mm) or thicker
and if the expected humidity exceeds 80 %, use heat insulation that is 13/16 in (20 mm) or
thicker. If heat insulation is used that is not as thick as speci
fi
ed, condensation may form
on the surface of the insulation.
In addition, use heat insulation with heat conductivity of 0.045 W/(m·K) or less (at 68°F
(20°C)).
4.3 Brazing connection (pipe connection)
4.3.1. Bending
pipes
• The pipes are shaped by your hands or pipe bender. Be careful not to collapse them.
• Do not bend the pipes in an angle more than 90°.
• When pipes are repeatedly bend or stretched, the material will harden, making it dif
fi
cult to
bend or stretch them any more. Do not bend or stretch the pipes more than 3 times.
CAUTION
To prevent breaking of the pipe, avoid sharp bends.
If the pipe is bent repeatedly at the same place, it will break.
4.3.2. Pipe
connection
CAUTION
Direct-expansion coils are shipped pressurized with dry nitrogen.
Do not leave piping open to the atmosphere unnecessarily. Water and water vapor are
detrimental to the refrigerant system. Until the piping is complete, recap the system and
charge with nitrogen at the end of each workday. Clean all piping connections before
soldering joints.
Failure to follow these procedures could result in personal injury or equipment damage.
• The gas and liquid pipes connections must be brazed.
• Be sure to braze them before performing any wiring work or installing the drain pipe.
Outer diameter of pipe [in (mm)]
AR12
AR18
AR24
AR30
AR36
AR48
AR60
Liquid pipe
1/4 (6.35) 3/8 (9.52) 3/8 (9.52) 3/8 (9.52) 3/8 (9.52) 3/8 (9.52) 3/8 (9.52)
Gas pipe
1/2
(12.70)
5/8
(15.88)
5/8
(15.88)
5/8
(15.88)
3/4
(19.05)
3/4
(19.05)
3/4
(19.05)
(1) Remove the
fi
lter panel,
fi
lter and coil access panels (left/right).
Screws
Coil access panel (left)
Coil access panel (right)
Air
fi
lter
Filter panel
