En-7
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 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 70-80 %, use heat insulation that is 15 mm or thicker and
if the expected humidity exceeds 80 %, use heat insulation that is 20 mm or thicker.
If heat insulation is used that is not as thick as specified, 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 20 °C).
4.3. Flare connection (Pipe connection)
WARNING
• Tighten the flare nuts with a torque wrench using the specified tightening method.
Otherwise, the flare nuts could break after a prolonged period, causing refrigerant to
leak and generate a hazardous gas if the refrigerant comes into contact with a flame.
4.3.1. Flaring
• Use special pipe cutter and flare tool exclusive for R410A.
(1)
Cut the connection pipe to the necessary length with a pipe cutter.
(2)
Hold the pipe downward so that cuttings will not enter the pipe and remove any
burrs.
(3)
Insert the flare nut (always use the flare nut attached to the indoor and outdoor units
respectively) onto the pipe and perform the flare processing with a flare tool. Use
the special R410A flare tool, or the conventional flare tool. Leakage of refrigerant
may result if other flare nuts are used.
(4)
Protect the pipes by pinching them or with tape to prevent dust, dirt, or water from
entering the pipes.
/
Die
Pipe
A
B
Check if [L] is flared uniformly
and is not cracked or scratched.
Pipe outside diameter
[mm (in.)]
Dimension A [mm]
Dimension B
-
0
0.4
[mm]
Flare tool for R410A,
clutch type
6.35 (1/4)
0 to 0.5
9.1
9.52 (3/8)
13.2
12.70 (1/2)
16.6
15.88 (5/8)
19.7
19.05 (3/4)
24.0
When using conventional flare tools to flare R410A pipes, the dimension A should be
approximately 0.5 mm more than indicated in the table (for flaring with R410A flare tools)
to achieve the specified flaring. Use a thickness gauge to measure the dimension A.
Width across
flats
Pipe outside
diameter [mm (in.)]
Width across flats
of Flare nut [mm]
6.35 (1/4)
17
9.52 (3/8)
22
12.70 (1/2)
26
15.88 (5/8)
29
19.05 (3/4)
36
4.3.2. Bending pipes
•
If pipes are shaped by hand, 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
difficult 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.
4.3.3. Pipe connection
CAUTION
•
Be sure to install the pipe against the port on the indoor unit correctly. If the centering
is improper, the flare nut cannot tighten smoothly. If the flare nut is forced to turn, the
threads will be damaged.
• Do not remove the flare nut from the indoor unit pipe until immediately before
connecting the connection pipe.
• Hold the torque wrench at its grip, keeping it at a right angle with the pipe, in order to
tighten the flare nut correctly.
• Tighten the flare nuts with a torque wrench using the specified tightening method.
Otherwise, the flare nuts could break after a prolonged period, causing refrigerant to
leak and generate a hazardous gas if the refrigerant comes into contact with a flame.
• Connect the piping so that the control box cover can easily be removed for servicing
when necessary.
• In order to prevent water from leaking into the control box, make sure that the piping
is well insulated.
When the flare nut is tightened properly by your hand, hold the body side coupling with
a separate spanner, then tighten with a torque wrench. (See the table below for the flare
nut tightening torques.)
Tighten with 2 wrenches.
Holding wrench
Flare nut
Connection pipe
Torque wrench
Indoor unit pipe
(Body side)
Flare nut [mm (in.)]
Tightening torque [N·m (kgf·cm)]
6.35 (1/4) dia.
16 to 18 (160 to 180)
9.52 (3/8) dia.
32 to 42 (320 to 420)
12.70 (1/2) dia.
49 to 61 (490 to 610)
15.88 (5/8) dia.
63 to 75 (630 to 750)
19.05 (3/4) dia.
90 to 110 (900 to 1,100)
4.4. Installing heat insulation
Install the heat insulation material after performing a refrigerant leak check (see the
Installation Manual for the outdoor unit for details).
4.4.1. COUPLER HEAT INSULATION
• Insulate with the coupler heat insulation (Accessories) around the gas pipe and liquid
pipe at indoor unit.
• After installing the coupler heat insulation, wrap both ends with vinyl tape so that
there is no gap.
• After affixing the coupler heat insulation, secure it with 2 binders (large), one on each
end of the insulation.
• Make sure that the binders overlap the heat insulation pipe.
Coupler heat
insulation
(Accessories)
Cover this portion with
heat insulation.
Binder (Large)
(Accessories)
Heat insulation
CAUTION
• After checking for gas leaks (refer to the Installation Manual of the outdoor unit),
perform this section.
• Install heat insulation around both the large (gas) and small (liquid) pipes. Failure to
do so may cause water leaks.
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