Refrigerant Piping - Toshiba MMD-AP0071SH-C Service Manual

7

REFRIGERANT PIPING

• If refrigerant gas has leaked during the installation work, ventilate the room immediately.
• If the leaked refrigerant gas comes in contact with fire, noxious gas may generate.
• After the installation work, confirm that refrigerant gas does not leak.
• If refrigerant gas leaks into the room and flows near a fire source, such as a cooking range, noxious gas may
generate.
REQUIREMENT
When the refrigerant pipe is long, set the support brackets to fix the pipe with 2.5 to 3m intervals. If the pipe is
not fixed, abnormal sound may generate.
Be sure to use the flare nuts attached to the indoor unit or those fro R410A.
Permissible pipe length and permissible height difference
They are different according to the used outdoor unit. For details, refer to the Installation Manual attached to the
outdoor unit.
Piping material and dimensions
Piping material Phosphor deoxidization joint-less pipe for air conditioner
Model MMD-
Gas side
Pipe size (mm)
Liquid side
• Use a clean and new pipe, and check that impurity such as dust, oil, moisture, etc. does not adhere in the pipe.
Pipe forming/End positioning
Flaring
1. Cut the pipe with a pipe cutter.
OK NO GOOD
90˚
Obliquity Roughness Warp
2. 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.
WARNING
AP007 to AP012 AP015 to AP018
Ø9.5 Ø12.7
Ø6.4 Ø6.4
A
• Flaring diam. meter size :
A (Unit : mm)
+0
A
Outer diam. of - 0.4
copper pipe
R410A
6.4 9.1
9.5 13.2
12.7 16.6
* 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.
• Projection margin in flaring :
B (Unit : mm)
Rigid (Clutch type)
R410A tool used Conventional tool used
Outer diam. of
copper pipe
R410A R22 R410A R22
6.4 0 to 0.5 (Same as left) 1.0 to 1.5 0.5 to 1.0
9.5 0 to 0.5 (Same as left) 1.0 to 1.5 0.5 to 1.0
12.7 0 to 0.5 (Same as left) 1.0 to 1.5 0.5 to 1.0
Imperial (Wing nut type)
Outer diam. of copper pipe R410A R22
6.4 1.5 to 2.0 1.0 to 1.5
9.5 1.5 to 2.0 1.0 to 1.5
12.7 2.0 to 2.5 1.5 to 2.0
Connection of refrigerant pipe
Connect all the refrigerant pipes with flare connecting
work.
• Since the atmospheric pressure only is sealed
as the sealing gas, it is not abnormal that
"Pushu..." sound is not heard when the flare
nut is removed.
• Be sure to use a double spanner for pipe
connecting work of the indoor unit.
Work using double spanner
• Refer to the following table for tightening torque.
Connecting pipe Tightening torque Re-tightening
outer dia. (mm) (N•m) torque (N•m)
Ø6.4 14 to18 (1.4 to 1.8 kgf•m) 18 (1.8 kgf•m)
Ø9.5 33 to 42 (3.3 to 4.2 kgf•m) 42 (4.2 kgf•m)
Ø12.7 50 to 62 (5.0 to 6.2 kgf•m) 62 (6.2 kgf•m)
• Tightening torque of flare pipe connections
B
Pressure of R410A is higher than that of R22 by
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
refrigerating cycle.
REQUIREMENT
If an excessive torque is applied, the nut
may crack depending on the installation
conditions.
Airtight test/Air purge, etc.
For airtight test, air purge, addition of refrigerant, and
gas leak check, follow the Installation Manual attached
to the outdoor unit.
REQUIREMENT
Be sure to use the tool such as charge hose
exclusive to R410A.
Do not turn on the power until the airtight test and
the vacuuming have finished. (If turning on the
power, the incorporated PMV is closed fully and
the period until the vacuuming finishes elongates.
Open fully valves of 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 (R410A, R134a, etc.).