Toshiba RAS-M07G3DV-E Service Manual page 71

10-7. Refrigerant piping
CAUTION
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. Use the
flare nut attached with the indoor unit or R32/
R410A flare nut.
• 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 refabricated.
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
Model RAS-
M07,10,13
M16
M22,24
Connecting refrigerant piping
Flaring
1. Cut the pipe by 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 R32/R410A refrigerant. The flaring
dimensions for R32/R410A are different from the ones used for the
conventional R22 refrigerant. A new flare tool manufactured for use with the
R32/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)
R32 or R410A tool
Outer dia. of copper pipe
6.4, 9.5
12.7
Flaring diameter size: A (Unit: mm)
Outer dia. of copper pipe
6.4
9.5
12.7
Pipe size (mm)
Gas side Liquid side
Ø9.5 Ø6.4
Ø12.7 Ø6.4
Ø12.7 Ø6.4
Conventional tool used
used
0 to 0.5 1.0 to 1.5
A
+0
–0.4
9.1
13.2
16.6
• 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.
• 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 table below.
Outer dia. of connecting pipe (mm)
6.4
9.5
12.7
• Tightening torque of flare pipe connections.
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.
Airtight test / Air purge, etc.
For air tightness test, vacuum drying and adding refrigerant, refer to the
Installation Manual attached tothe outdoor unit.
Open the valve fully
Open the valve of the outdoor unit fully.
Heat insulation process
Apply heat insulation for the pipes separately at liquid side and gas side.
• For the heat insulation to the pipes at gas side, use the material with heat-
resisting temperature 120 °C or higher.
• To use the attached heat insulation pipe, apply the heat insulation to the pipe
connecting section of the indoor unit securely without gap.
REQUIREMENT
• Apply the heat insulation to the pipe connecting section of the indoor unit
securely up to the root without exposure of the pipe. (The pipe exposed to
the outside causes water leak.)
• Wrap heat insulator with its slits facing up (ceiling side).
Wrap the pipe with the attached heat insulator
without any gap between the indoor unit.
Indoor unit
Heat insulation
pipe
(Accessory)
– 70 –
Work using double spanner
Tightening torque (N•m)
14 to 18 (1.4 to 1.8 kgf•m)
34 to 42 (3.4 to 4.2 kgf•m)
49 to 61 (4.9 to 6.1 kgf•m)
The seam must be faced
upward (ceiling side).
Flare nut
Heat insulator
of the pipe
Banding band
Union
(Locally
procured)