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7
Refrigerant piping
Refrigerant piping
1.
Use the following items for the refrigerant
piping.
Material : Seamless phosphorous deoxidized
copper pipe.
Wall thickness : 0.8 mm or more Ø12.7 mm
(C1220T-0)
1.0 mm or more for Ø28.6 mm
(C1220T-1/2H).
Do not use any copper pipes with a wall
thickness less than these thicknesses.
2. Flare nut and
fl
are works are also different from
those of the conventional refrigerant.
Take out the
fl
are nut attached to the main unit of
the air conditioner, and use it.
REQUIREMENT
When the refrigerant pipe is long, provide support
brackets at intervals of 2.5 to 3 m to clamp the
refrigerant pipe. Otherwise, abnormal sound may
be generated.
CAUTION
Important 4 points for piping work
1. Remove dust and moisture from the inside of the
connecting pipes.
2. Tight connection (between pipes and unit)
3. Evacuate the air in the connecting pipes using
VACUUM PUMP.
4. Check the gas leakage. (Connected points)
Pipe size
Pipe size
Gas side
28.6 mm
Liquid side
12.7 mm
Liquid side refrigerant pipe
connection
Permissible piping length and height
difference
They vary according to the outdoor unit.
For details, refer to the Installation Manual attached to
the outdoor unit.
Flaring
y
Cut the pipe with a pipe cutter.
Remove burrs completely.
Remaining burrs may cause gas leakage.
y
Insert a
fl
are nut into the pipe, and
fl
are the pipe.
As the
fl
aring sizes of R410A differ from those of
refrigerant R22, the
fl
are tools newly manufactured
for R410A are recommended.
However, the conventional
tools can be used by adjusting
projection margin of the copper
pipe.
B
q
Projection margin in
fl
aring: B (Unit: mm)
Rigid (Clutch type)
Outer dia. of
copper pipe
R410A tool used
Conventional
tool used
R410A
R410A
12.7
0 to 0.5
1.5 to 2.0
q
Flaring diameter size: A (Unit: mm)
Outer dia. of copper pipe
A
+0
-0.02” (–0.4)
R410A
12.7
16.6
* In case of
fl
aring for R410A with the
conventional
fl
are tool, pull it out approx.
0.5 mm more than that for R22 to adjust
to the speci
fi
ed
fl
are size.
The copper pipe gauge is useful for
adjusting projection margin size.
A
Tightening connection
CAUTION
Do not apply excessive torque. Otherwise, the
nut may crack depending on the conditions.
(Unit: N•m)
Outer dia. of copper pipe
Tightening torque
12.7 mm (dia.)
50 to 62 (5.0 to 6.2 kgf•m)
q
Tightening torque of
fl
are pipe connections
Pressure of R410A is higher than that of R22.
(Approx. 1.6 times) Therefore, using a torque wrench,
tighten the
fl
are pipe connecting sections which
connect the indoor and outdoor units of the speci
fi
ed
tightening torque.
Incorrect connections may cause not only a gas leak,
but also a trouble of the refrigeration cycle.
Align the centres of the connecting pipes and tighten
the
fl
are nut as far as possible with your
fi
ngers. Then
tighten the nut with a spanner and torque wrench as
shown in the
fi
gure.
Half union
Flare nut
Externally
threaded side
Internally
threaded side
Use a wrench to secure.
Use a torque wrench to tighten.
REQUIREMENT
Tightening with an excessive torque may crack the
nut depending on installation conditions.
Tighten the nut within the speci
fi
ed tightening
torque.
Gas side refrigerant pipe
connection
y
Turn up the pipe heat insulator to the unit side.
y
Wrap the pipe with wet cloth.
Turn up pipe heat
insulator
Remove the all
brazed part.
Wet cloth
y
Remove the cup on the gas side piping by using a
brazing machine.
CAUTION
y
Do not burn the pipe heat insulator.
y
Be careful for the
fl
ame, due to the brazing
process on the ceiling.
Remove the cap
Connection pipe
Locally procured
Ø28.6 mm
Attached joint part
y
Braze the attached joint part to the gas side piping
and braze the connection piping to the joint part.
Brazing
Braze all around
Brazing
y
Turn back the pipe heat insulator and tie up with a
banding band.
Tie up with a banding
band.
Piping with outdoor unit
For details of installation, refer to the Installation
Manual of the outdoor unit.
Evacuation
Using a vacuum pump, perform vacuuming from the
charge port of valve of the outdoor unit.
For details, follow to the Installation Manual attached
to the outdoor unit.
y
Never use the refrigerant sealed in the outdoor unit
for evacuation.
REQUIREMENT
For the tools such as charge hose, etc., use those
manufactured exclusively for R410A.
