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• When tightening the flare nut, use two
spanners.
Do not apply the double
spanner work here.
Refrigerant leakage shall
occur.
Double Spanner Work
Check to ensure that no pressure increase is
observed one hour after vacuum pumping
completion.
Table. 5.3 Tightening Work of Flare Nut
Required Torque
Pipe Size
φ6.35
(1/4)
φ9.53
(3/8)
φ12.7
(1/2)
φ15.88 (5/8)
φ19.05 (3/4)
Bolt for Flange
53 to 75N-m
(Factory-Supplied)
• Evacuation and refrigerant charging procedure
should be performed according to the following
instructions and Fig. 5.5.
(1) The stop valve has been closed before
shipment, however, make sure that the
stop valves are closed completely.
(2) Connect the indoor unit and the outdoor
unit with field-supplied refrigerant piping.
Suspend the refrigerant piping at specified
points and prevent the refrigerant piping
from touching weak parts of the building
such as wall, ceiling, etc.
(Abnormal sound may occur due to the
vibration of the piping. Pay special
attention in case of short piping length.)
(3) Connect the gauge manifold using
charging hoses with a vacuum pump or a
nitrogen cylinder to the check joints of the
liquid line and the gas line stop valves.
Perform the air-tight test.
Connect a mani-fold gauge to the check
joints of the liquid and gas stop valves in
the outdoor unit. Do not open the stop
valves. Apply nitrogen gas pressure of
4.15MPa for FSN series.
Tightening Work for Stop Valve
Tightening Torque
20N-m
(2 kg-m)
40N-m
(4 kg-m)
60N-m
(6 kg-m)
80N-m
(8 kg-m)
100N-m
(10 kg-m)
(5.4 to 7.6 kg-m)
(4) Check for any gas leakage at the flare nut
connections, or brazed parts by gas
leakage tester or by use of a foaming
agent.
Procedure
Completion
Applying
of Ref.
Nitrogen
Piping
Gas
Repairing
of Leakage
(5) Connect a mani-fold gauge to the check
joints at the both sides.
Continue vacuum pumping work until the
pressure reaches -756mmHg or lower for
one to two hours.
After vacuum pumping work, stop the
mani-fold valve's valve, stop the vacuum
pump and leave it for one hour. Check to
ensure that the pressure in the manifold
gauge does not increase.
NOTES:
1. If tools or measuring instruments come
into contact with the refrigerant, ensure
they are tools specified for use with
R410A.
2. If vacuum degree of -756mmHg is not
available, it is considered that there is a
gas leakage. Check for any gas leakage
once again. If no leakage exists,
operate the vacuum pump for one to two
hours.
(6) To charge refrigerant, connect the gauge
manifold using charging hoses with a
refrigerant charging cylinder to the check
joint of the liquid line stop valve.
(7) Fully open the gas line stop valve and
slightly open the liquid line stop valve.
(8) Charge refrigerant by opening the gauge
manifold valve.
(9) Charge the required refrigerant within the
difference range of ±0.5kg by operating the
system in cooling.
(10) Fully open the liquid line stop valve after
completing refrigerant charge.
(11) Continue cooling operation for more than
10 minutes to circulate the refrigerant.
Check of
Pressure
Pass
Decrease
Part
9
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