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7
Refrigerant piping
CAUTION
When the refrigerant pipe is long, provide support
brackets at intervals of 2.5 m to 3 m to clamp the
refrigerant pipe. Otherwise, abnormal sound may be
generated.
Use the flare nut attached with the indoor unit or R410A
flare nut.
Permissible piping length and
height difference
They vary depending on the outdoor unit. For details,
refer to the Installation Manual attached to the outdoor
unit.
Pipe size
Connecting refrigerant piping
Flaring
1. Cut the pipe with a pipe cutter.
Remove burrs completely. (Remaining burrs may
cause gas leakage.)
2. Insert a flare nut into the pipe, and flare the pipe.
Use the flare nut provided with the unit or the one
used for the R410A refrigerant. The flaring
dimensions for R410A are different from the ones
used for the conventional R22 refrigerant. A new
flare tool manufactured for use with the R410A
refrigerant is recommended, but the conventional
tool can still be used if the projection margin of the
copper pipe is adjusted to be as shown in the
following table.
Projection margin in flaring: B (Unit: mm)
Flaring diameter size: A (Unit: mm)
* In case of flaring for R410A with the conventional
flare tool, pull it out approx. 0.5 mm more than that
for R22 to adjust to the specified flare size. The
copper pipe gauge is useful for adjusting projection
margin size.
Model MMD-
Pipe size (mm)
Gas side
Liquid side
Outer dia. of
copper pipe
R410A tool used
Conventional
tool used
6.4, 9.5
0 to 0.5
1.0 to 1.5
12.7, 15.9
Outer dia. of copper pipe
A +0
–0.4
1
.
9
4
.
6
2
.
3
1
5
.
9
6
.
6
1
7
.
2
1
7
.
9
1
9
.
5
1
The sealed gas was sealed at the atmospheric
pressure so when the flare nut is removed, there will
no “whooshing” sound: This is normal and is not
indicative of trouble.
Use two wrenches to connect the indoor unit pipe.
Use the tightening torque levels as listed in the
following table.
Tightening torque of flare pipe connections.
Pressure of R410A is higher than that of R22.
(Approx. 1.6 times) Therefore, using a torque
wrench, tighten the flare pipe connecting sections
which connect the indoor and outdoor units of the
specified tightening torque.
Incorrect connections may cause not only a gas leak,
but also a trouble of the refrigeration cycle.
CAUTION
Tightening with an excessive torque may crack the nut
depending on installation conditions.
Evacuation
Perform vacuuming from the charge port of valve of the
outdoor unit by using a vacuum pump.
For details, follow to the Installation Manual attached to
the outdoor unit.
Do not use the refrigerant sealed in the outdoor unit
for evacuation.
REQUIREMENT
For the tools such as charge hose, use those
manufactured exclusively for R410A.
Refrigerant amount to be added
For addition of the refrigerant, add refrigerant “R410A”
referring to the attached Installation Manual of outdoor
unit.
Use a scale to charge the refrigerant of specified
amount.
REQUIREMENT
Charging an excessive or too little amount of
refrigerant causes a trouble of the compressor.
Charge the refrigerant of specified amount.
A personnel who charged the refrigerant should write
down the pipe length and the added refrigerant
amount in the F-GAS label of the outdoor unit. It is
necessary to fix the compressor and refrigeration
cycle malfunction.
Open the valve fully
Open the valve of the outdoor unit fully. A 4 mm-
hexagonal wrench is required for opening the valve.
For details, refer to the Installation Manual attached to
the outdoor unit.
Gas leak check
Check with a leak detector or soap water whether gas
leaks or not, from the pipe connecting section or cap of
the valve.
REQUIREMENT
Use a leak detector manufactured exclusively for HFC
refrigerant (R410A, R134a).
Outer dia. of connecting
pipe (mm)
Tightening torque (N
m)
8
1
o
t
4
1
4
.
6
2
4
o
t
4
3
5
.
9
1
6
o
t
9
4
7
.
2
1
7
7
o
t
3
6
9
.
5
1
Work using double spanner
23-EN
24-EN
AP018
Ø12.7
Ø6.4
AP024 to AP056
Ø15.9
Ø9.5
1117065599 (01)_EN.indd 13
1117065599 (01)_EN.indd 13
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01/07/15 3:42 PM
