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(4) When the fl are nut is tightened properly by your hand, use a torque wrench to
fi nally tighten it.
Holding spanner
Body side
90°
Torque wrench
CAUTION
Hold the torque wrench at its grip, keeping it in the right angle with the pipe, in order to
tighten the fl are nut correctly.
Flare nut [mm (in.)]
Tightening torque [N·m (kgf·cm)]
6.35 (1/4) dia.
16 to 18 (160 to 180)
9.52 (3/8) dia.
32 to 42 (320 to 420)
12.70 (1/2) dia.
49 to 61 (490 to 610)
15.88 (5/8) dia.
63 to 75 (630 to 750)
19.05 (3/4) dia.
90 to 110 (900 to 1100)
CAUTION
Fasten a fl are nut with a torque wrench as instructed in this manual. If fastened too
tight, the fl are nut may be broken after a long period of time and cause a leakage of
refrigerant.
During installation, make sure that the refrigerant pipe is attached fi rmly before you
run the compressor. Do not operate the compressor under the condition of refrigerant
piping not attached properly with 3-way valves open. This may cause abnormal
pressure in the refrigeration cycle that leads to breakage and even injury.
5.5. Sealing test
WARNING
Before operating the compressor, install the pipes and securely connect them. Otherwise,
if the pipes are not installed and if the valves are open when the compressor operates, air
could enter the refrigeration cycle. If this happens, the pressure in the refrigeration cycle will
become abnormally high and cause damage or injury.
After the installation, make sure there is no refrigerant leakage. If the refrigerant leaks
into the room and becomes exposed to a source of fi re such as a fan heater, stove, or
burner, it produces a toxic gas.
Do not subject the pipes to strong shocks during the sealing test. It can rupture the
pipes and cause serious injury.
CAUTION
Do not block the walls and the ceiling until the sealing test and the charging of the
refrigerant gas have been completed.
For maintenance purposes, do not bury the piping of the outdoor unit.
• After connecting the pipes, perform a sealing test.
• Make sure that the 3-way valves are closed before performing a sealing test.
• Pressurize nitrogen gas to 4.15 MPa to perform the sealing test.
• Add nitrogen gas to both the liquid pipes and the gas pipes.
• Check all fl are connections and welds. Then, check that the pressure has not
decreased.
• Compare the pressures after pressurizing and letting it stand for 24 hours, and check
that the pressure has not decreased.
* When the outdoor air temperature changes 5 °C, the test pressure changes
0.05 MPa. If the pressure has dropped, the pipe joints may be leaking.
• If a leak is found, immediately repair it and perform the sealing test again.
• After completing the sealing test, release the nitrogen gas from both valves.
• Release the nitrogen gas slowly.
En-9
5.6. Vacuum process
CAUTION
Perform a refrigerant leakage test (air tightness test) to check for leaks using nitrogen
gas while all valves in the outdoor unit are closed. (Use the test pressure indicated on
the nameplate.)
Be sure to evacuate the refrigerant system using a vacuum pump.
The refrigerant pressure may sometimes not rise when a closed valve is opened after
the system is evacuated using a vacuum pump. This is caused by the closure of the
refrigerant system of the outdoor unit by the electronic expansion valve. This will not
affect the operation of the unit.
If the system is not evacuated suffi ciently, its performance will drop.
Use a clean gauge manifold and charging hose that were designed specifi cally for use
with R32(R410A). Using the same vacuum equipment for different refrigerants may
damage the vacuum pump or the unit.
Do not purge the air with refrigerants, but use a vacuum pump to evacuate the system.
Always use a vacuum pump to purge the air.
Refrigerant for purging the air is not charged in the outdoor unit at the factory.
(1) Remove the cap, and connect the gauge manifold and the vacuum pump to the
charging valve by the service hoses.
(2) Vacuum the indoor unit and the connecting pipes until the pressure gauge indicates
–0.1 MPa (–76 cmHg).
(3) When –0.1 MPa (–76 cmHg) is reached, operate the vacuum pump for at least
60 minutes.
(4) Disconnect the service hoses and fi t the cap to the charging valve to the specifi ed
torque.
(5) Remove the blank caps, and fully open the spindles of the 3-way valves with a
hexagon wrench [Torque: 6~7 N·m (60 to 70 kgf·cm)].
(6) Tighten the blank caps of the 3-way valves to the specifi ed torque.
Tightening torque
6.35 mm (1/4 in.)
20 to 25 N·m (200 to 250 kgf·cm)
9.52 mm (3/8 in.)
20 to 25 N·m (200 to 250 kgf·cm)
Blank cap
12.70 mm (1/2 in.)
28 to 32 N·m (280 to 320 kgf·cm)
15.88 mm (5/8 in.)
30 to 35 N·m (300 to 350 kgf·cm)
19.05 mm (3/8 in.)
35 to 40 N·m (350 to 400 kgf·cm)
Charging port cap
12.5 to 16 N·m (125 to 160 kgf·cm)
Outdoor unit
Connecting pipe
Service hose
3-way valve (Gas)
with valve core
Blank cap
Cap
Charging port
Hexagon wrench
Use a 4 mm
hexagon wrench.
Gauge manifold
Lo
Hi
Vacuum pump
Service hose
CAUTION
Install insulation around both the gas and liquid pipes. Failure to do so may cause
water leaks.
Use insulation with heat resistance above 120 °C.
In addition, if the humidity level at the installation location of the refrigerant piping is
expected to exceed 70%, install insulation around the refrigerant piping. If the expected
humidity level is 70-80%, use insulation that is 15 mm or thicker, and if the expected
humidity level exceeds 80%, use insulation that is 20 mm or thicker.
If insulation is used that is not as thick as specifi ed, condensation may form on the
surface of the insulation.
In addition, use insulation with heat conductivity of 0.045 W/(m·K) or less (at 20 °C).
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