Refrigerant Piping - Toshiba MMD-AP0726HP-E Installation Manual

7

Refrigerant piping

Refrigerant piping
1. Use general copper pipes with a wall thickness
of 0.8 mm for Ø12.7 mm, and with a wall
thickness of 1.0 mm for Ø22.2 mm (half hard).
Do not use any copper pipes with a wall
thickness less than these thicknesses.
2. Flare nut and flare works are also different from
those of the conventional refrigerant.
Take out the flare nut attached to the main unit of
the air conditioner, and use it.
REQUIREMENT
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.
CAUTION
Important 4 points for piping work
1. Remove dust and moisture from the inside of the
connecting pipes.
2. Tight connection (between pipes and unit)
3. Evacuate the air in the connecting pipes using
VACUUM PUMP.
4. Check the gas leakage. (Connected points)
Pipe size
Gas side 22.2 mm
Pipe size
Liquid side 12.7 mm
Liquid side refrigerant pipe
connection
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.
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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 R410A differ from those of
refrigerant R22, the flare tools newly manufactured
for R410A are recommended.
However, the conventional
tools can be used by adjusting
projection margin of the copper
pipe.
q Projection margin in fl aring: B (Unit: mm)
Rigid (Clutch type)
Conventional
R410A tool used
Outer dia. of
tool used
copper pipe
R410A R410A
12.7 0 to 0.5 1.5 to 2.0
q Flaring dia meter size: A (Unit: mm)
+0
A
-0.02" (–0.4)
Outer dia. of copper pipe
R410A
12.7 16.6
* In case of fl aring for R410A with the
A
conventional fl are tool, pull it out approx.
0.5 mm more than that for R22 to adjust
to the specifi ed fl are size.
The copper pipe gauge is useful for
adjusting projection margin size.
Tightening connection
CAUTION
Do not apply excessive torque. Otherwise, the
nut may crack depending on the conditions.
Outer dia. of copper pipe Tightening torque
12.7 mm (dia.) 50 to 62 (5.0 to 6.2 kgf•m)
q Tightening torque of fl are pipe connections
B
Pressure of R410A is higher than that of R22.
(Approx. 1.6 times) Therefore, using a torque wrench,
tighten the fl are pipe connecting sections which
connect the indoor and outdoor units of the specifi ed
tightening torque.
Incorrect connections may cause not only a gas leak,
but also a trouble of the refrigeration cycle.
Align the centres of the connecting pipes and tighten
the fl are nut as far as possible with your fi ngers. Then
tighten the nut with a spanner and torque wrench as
shown in the fi gure.
Half union Flare nut
Externally
threaded side
Use a wrench to secure. Use a torque wrench to tighten.
REQUIREMENT
Tightening with an excessive torque may crack the
nut depending on installation conditions.
Tighten the nut within the specifi ed tightening
torque.
Gas side refrigerant pipe
connection
Turn up the pipe heat insulator to the unit side.
Wrap the pipe with wet cloth.
Turn up pipe heat
insulator
Wet cloth
Remove the all
brazed part.
Remove the cup on the gas side piping by using a
brazing machine.
– 14 –
CAUTION
Do not burn the pipe heat insulator.
Be careful for the flame, due to the brazing
process on the ceiling.
(Unit: N•m)
Connection pipe
Locally procured
Ø22.2 mm
Braze the connection piping to the joint part.
Braze all around
Turn back the pipe heat insulator and tie up with a
banding band.
Internally
Tie up with a banding
threaded side
band.
Piping with outdoor unit
For details of installation, refer to the Installation
Manual of the outdoor unit.
Evacuation
Using a vacuum pump, perform vacuuming from the
charge port of valve of the outdoor unit.
For details, follow to the Installation Manual attached
to the outdoor unit.
Never use the refrigerant sealed in the outdoor unit
for evacuation.
REQUIREMENT
For the tools such as charge hose, etc., use those
manufactured exclusively for R410A.
Remove the cap
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EN
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