102
SMMS 2-way Air Discharge Cassette Type
Installation Manual
17
EN-33
EN-34
6
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.
Be sure to 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.
Pi
pe size
Conn
ecting 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)
Model: MMU-
Pipe size (mm)
Gas side
Liquid side
AP007 to AP012
Ø9.5
Ø6.4
AP015 to AP018
Ø12.7
Ø6.4
AP024 to AP056
Ø15.9
Ø9.5
Outer diam. 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
Flaring dia. meter 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.
• 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.
• Be absolutely sure to use two wrenches to connect the
indoor unit pipe.
• Use the tightening torque levels as listed in the table
below.
• 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.
Air
tight test/Air purge, etc.
For airtight test, air purge, addition of refrigerant, and gas
leak check, refer to the Installation Manual attached to
the outdoor unit.
CAUTION
Do not supply power to the indoor unit until the airtight
test and vacuuming are completed. (If the indoor unit is
powered on, the pulse motor valve is fully closed, which
extends the time for vacuuming.)
Outer diam. of copper
pipe
A
6.4
9.1
9.5
13.2
12.7
16.6
15.9
19.7
+0
–0.4
Work using double spanner
Outer dia. of connecting
pipe (mm)
Tightening torque (N•m)
6.4
14 to 18 (1.4 to 1.8 kgf•m)
9.5
33 to 42 (3.3 to 4.2 kgf•m)
12.7
50 to 62 (5.0 to 6.2 kgf•m)
15.9
63 to 77 (6.3 to 7.7 kgf•m)
