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■ Flare connection
• Be sure to install the pipe against the port on the indoor unit and the outdoor unit
correctly. If the centering is improper, the flare nut cannot be tightened smoothly.
If the flare nut is forced to turn, the threads will be damaged.
• Do not remove the flare nut from the outdoor unit pipe until immediately before
connecting the connection pipe.
• After installing the piping, make sure that the connection pipes do not touch the
compressor or outer panel. If the pipes touch the compressor or outer panel, they will
vibrate and produce noise.
(1) Detach the caps and plugs from the pipes.
(2) Center the pipe against the port on the outdoor unit, and then turn the flare nut by hand.
To prevent gas leakage, coat the flare
surface with alkylbenzene oil (HAB).
Do not use mineral oil.
(3) Attach the connection
pipe.
2-way valve (Liquid)
3-way valve (Gas)
Flare nut
Flare nut
(4) When the flare nut is
tightened properly by your
hand, use a torque wrench
to finally tighten it.
• Hold the torque wrench at its grip, keeping it in a right angle with the pipe, in order to
tighten the flare nut correctly.
• Outer panel may be distorted if fastened only with a wrench. Be sure to fix the elemen-
tary part with a holding wrench (spanner) and fasten with a torque wrench (refer to below
diagram). Do not apply force to the blank cap of the valve or hang a wrench, etc., on the
cap. If blank cap is broken, it may cause leakage of refrigerant.
Flare nut [mm (in.)]
6.35 (1/4) dia.
9.52 (3/8) dia.
12.70 (1/2) dia.
15.88 (5/8) dia.
19.05 (3/4) dia.
• Fasten a flare nut with a torque wrench as instructed in this manual. If fastened too
tight, the flare 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 firmly 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 pres-
sure in the refrigeration cycle that leads to breakage and even injury.
CAUTION
Connection pipe
(Liquid)
UNIT B
UNIT A
Connection pipe (Gas)
Holding spanner
Body side
Torque wrench
CAUTION
Tightening torque [N·m (kgf·cm)]
16 to 18 (160 to 180)
32 to 42 (320 to 420)
49 to 61 (490 to 610)
63 to 75 (630 to 750)
90 to 110 (900 to 1100)
CAUTION
3.6. Sealing test
• 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 compres-
sor 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 fire 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.
• 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 flare 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.
* W hen 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.
3.7. Vacuum process
• Always use a vacuum pump to purge the air.
• Refrigerant for purging the air is not charged in the outdoor unit at the factory.
• Refrigerant must not be discharged into atmosphere.
• Use a vacuum pump, gauge manifold and charge hose for R32 exclusively. Using the
same vacuum for different refrigerants may damage the vacuum pump or the unit.
• After connecting the piping, check the joints for gas leakage with gas leak detector or
soapy water.
■ Checking gas leakage and purging air
Gas leak checks are performed using either vacuum or nitrogen gas, so select the proper
one depending on the situation.
Checking gas leaks with vacuum:
(1) Check if the piping connections are secure.
(2) Remove the cap of 3-way valve, and connect the gauge manifold charge hoses to the
charging port of the 3-way valve.
(3) Open the valve of the gauge manifold fully.
(4) Operate the vacuum pump and start pump down.
(5) Check that the compound pressure gauge reads -0.1 MPa (76 cmHg), operate the
vacuum pump for 30 minutes or more in each valve.
(6) At the end of pump down, close the valve of the gauge manifold fully and stop the
vacuum pump.
(It checks that leave as it is for about 10 minutes, and a needle does not return.)
(7) Disconnect the charge hose from the 3-way valve charging port.
(8) Remove the blank caps, and fully open the spindles of the 2-way and 3-way valves
with a hexagon wrench.
[torque: 6 to 7 N·m (60 to 70 kgf·cm)].
(9) Tighten the blank caps and charging port cap of the 2-way valve and 3-way valve to
the specified torque.
Checking gas leaks with nitrogen gas:
(1) Check if the piping connections are secure.
(2) Remove the cap of 3-way valve, and connect the gauge manifold charge hoses to the
charging port of the 3-way valve.
(3) Pressurize with nitrogen gas using the 3-way valve charging port.
(4) Do not pressurize up to the specified pressure all at once but do so gradually.
1 Increase the pressure up to 0.5 Mpa (5 kgf/cm2), let it sit for about five minutes
and then check for any decrease in pressure.
2 Increase the pressure up to 1.5 Mpa (15 kgf/cm2), let it sit for about five minutes
and then check for any decrease in pressure.
3 Increase the pressure up to the specified pressure (the pressure designed for the
product) and then make a note of it.
(5) Let it sit at the specified pressure and if there is no decrease in pressure then it is
satisfactory. If a pressure decrease is confirmed, there is a leak, so it is necessary to
specify the leak location and make minor adjustments.
WARNING
CAUTION
CAUTION
En-9
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