Toshiba MMD-AP0481HF2UL Service Manual page 91
Multi type air-conditioner
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Also See for MMD-AP0481HF2UL:
- Installation manual (46 pages) ,
- Owner's manual (20 pages) ,
- Service manual (97 pages)
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9
Refrigerant piping
CAUTION
When the refrigerant pipe is long, provide support
brackets at intervals of 8'2" to 9'10" (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.
Use general copper pipes with a wall thickness of 0.03"
(0.8 mm) for Ø1/2" (12.7 mm), and with a wall thickness
of 0.04" (1.0 mm) for Ø7/8" (22.2 mm) (half hard).
Do not use any copper pipes with a wall thickness less
than these thicknesses.
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 MMD-
AP048
AP072, AP096
Ø5/8"
Gas side
(15.9 mm)
(22.2 mm)
Pipe size
(Unit: in (mm))
Ø3/8"
Liquid side
(12.7 mm)
(9.5 mm)
• The pipe (Ø7/8" (22.2 mm)) at gas side is connected
with brazing.
Liquid side refrigerant pipe
connection
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.
21-EN
Projection margin in flaring: B (Unit: in (mm))
Outer dia. of
R410A tool used
copper pipe
3/8" (9.5)
0 - 0.02"
(0 - 0.5)
1/2" (12.7), 5/8" (15.9)
Flaring diameter size: A (Unit: in (mm))
Outer dia. of
+0
A
copper pipe
–0.4
3/8" (9.5)
0.52" (13.2)
1/2" (12.7)
0.65" (16.6)
5/8" (15.9)
0.78" (19.7)
* In case of flaring for R410A with the conventional
flare tool, pull it out approx. 0.02" (0.5 mm) more than
that for R22 to adjust to the specified flare size. The
copper pipe gauge is useful for adjusting projection
Ø7/8"
margin size.
• The sealed gas was sealed at the atmospheric
Ø1/2"
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.
Work using double spanner
• Use the tightening torque levels as listed in the table
below.
Outer dia. of connecting
Tightening torque
pipe (mm)
(Unit: ft•lbs (N•m))
3/8" (9.5)
24 -31 (33 - 42)
1/2" (12.7)
37- 46 (50 - 62)
5/8" (15.9)
46 -57 (63 -77)
– 11 –
• 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
Conventional
specified tightening torque.
tool used
Incorrect connections may cause not only a gas leak,
0.04" - 0.06"
but also a trouble of the refrigeration cycle.
(1.0 - 1.5)
CAUTION
Tightening with an excessive torque may crack the nut
depending on installation conditions.
Gas side refrigerant pipe
connection
* The brazing connections on the gas side are
AP072 and AP096 models.
• Turn up the pipe heat insulator to the unit side.
• Wrap the pipe with wet cloth.
Wet cloth
• Remove the cup on the gas side piping by using a
brazing machine.
CAUTION
Do not burn the pipe heat insulator.
• Braze the connection piping to the joint part.
Braze all around
• Turn back the pipe heat insulator and tie up with a
banding band.
Airtight test / air purge, etc.
For air tightness test, adding refrigerant, 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.)
Open the valve fully
Open the valve of the outdoor unit fully.
Turn up pipe heat
insulator
Heat insulation process
Apply heat insulation for the pipes separately at liquid
side and gas side.
Remove the all
• For the heat insulation to the pipes at gas side, use
brazed part.
the material with heat-resisting temperature 248°F
(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
Remove the cap.
without exposure of the pipe. (The pipe exposed to the
outside causes water leak.)
• Wrap heat insulator with its slits facing up (ceiling
side).
Indoor unit
Connection pipe locally
procured Ø7/8" (22.2 mm)
Heat insulation pipe
(Accessory)
Tie up with a banding band.
Flare nut
Union
Heat insulator of
the pipe
Banding band
(Locally procured)
22-EN
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