6
Refrigerant piping
CAUTION
CAUTION
Use flare nuts that are included with the unit. Using
different flare nuts may cause refrigerant gas leakage.
Refrigerant piping
Use the following item for the refrigerant piping.
Material: Seamless phosphorous deoxidized
copper pipe.
6.35, 9.52, 12.7 Wall thickness 0.8 mm or more
15.88 Wall thickness 1.0 mm or more
REQUIREMENT
When the refrigerant pipe is long, provide support
brackets at intervals of 2.5 - 3 m to clamp the refrigerant
pipe. Otherwise, abnormal sound may be generated.
CAUTION
CAUTION
IMPORTANT 4 POINTS FOR PIPING WORK
1. Reusable mechanical connectors and flared joints are
not allowed indoors. When mechanical connectors
are reused indoors, sealing parts shall be renewed.
When flared joints are reused indoors, the flare part
shall be re-fabricated.
2. Tight connection (between pipes and unit)
3. Evacuate the air in the connecting pipes by using
VACUUM PUMP.
4. Check the gas leakage. (Connected points)
Pipe size
Model
HM80, HM110,
RAV-
HM56 type
name
Gas side
12.7 mm
Pipe size
Liquid side
6.4 mm
105-EN
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
• Cut the pipe with a pipe cutter.
Remove burrs completely.
Remaining burrs may cause gas leakage.
• Insert a flare nut into the pipe, and flare the pipe.
As the flaring sizes of R32 or R410A differ from those
of refrigerant R22, the flare tools newly
manufactured for R32 or R410A are recommended.
However, the conventional
tools can be used by adjusting
projection margin of the
copper pipe.
▼Projection margin in
flaring: B (Unit: mm)
Rigid (Clutch type)
Outside diameter
R32 or R410A
size
tool used
6.4, 9.5
0 - 0.5
12.7, 15.9
▼Flaring dia. meter size: A (Unit: mm)
Outside diameter
+0
A
size
–0.4
6.4
9.1
9.5
13.2
12.7
16.6
15.9
19.7
HM140 type
CAUTION
CAUTION
15.9 mm
9.5 mm
• Do not scratch the inner surface of the flared part
when removing burrs.
• Flare processing under the condition of scratches on
the inner surface of flare processing part will cause
refrigerant gas leak.
• Check that the flared part is not scratched, deformed,
stepped, or flattened, and that there are no chips
adhered or other problems, after flare processing.
• Do not apply refrigerating machine oil to the flare
surface.
– 53 –
Tightening connection
CAUTION
CAUTION
Do not apply excessive torque. Otherwise, the nut may
crack depending on the conditions.
Outside diameter size
6.4 mm
9.5 mm
12.7 mm
15.9 mm
▼Tightening torque of flare pipe connections
Incorrect connections may cause not only a gas leak,
but also a trouble of the refrigeration cycle.
Align the centers of the connecting pipes and tighten
B
the flare nut as far as possible with your fingers. Then
tighten the nut with a spanner and torque wrench as
shown in the figure.
Conventional
tool used
1.0 - 1.5
Work using two spanner
REQUIREMENT
Tightening with an excessive torque may crack the nut
A
depending on installation conditions.
Tighten the nut within the specified tightening torque.
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.
Unit: N•m
REQUIREMENT
Tightening torque
For the tools such as charge hose, use those
14 - 18
manufactured exclusively for R32 or R410A.
34 - 42
49 - 61
Refrigerant amount to be added
68 - 82
For addition of the refrigerant, add refrigerant "R32"
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 (R32, R410A, R134a).
106-EN