En-20
8.2. Vacuum process
CAUTION
Do not turn on the power unless all operations are complete.
If the system is not evacuated sufficiently, its performance will drop.
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.
Use a clean gauge manifold and charging hose that were designed specifically for use
with 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.
• If moisture might enter the piping, follow below. (i.e., if doing work during the rainy
season, if the actual work takes long enough that condensation may form on the
inside of the pipes, if rain might enter the pipes during work, etc.)
• After operating the vacuum pump for 2 hours, pressurize to 0.05 MPa (i.e., vacuum
breakdown) with nitrogen gas, then depressurize down to -100.7 kPa (-755 mmHg) for
an hour using the vacuum pump (vacuum process).
• If the pressure does not reach -100.7 kPa (-755 mmHg) even after depressurizing for
at least 2 hours, repeat the vacuum breakdown - vacuum process.
After vacuum process, maintain the vacuum for an hour and make sure the pressure
does not rise by monitoring with a vacuum gauge.
8.2.1 Evacuation procedure
(1) Remove the caps of the gas pipe and liquid pipe and check that the valves are
closed.
(2) Remove the charging cap.
(3) Connect a vacuum pump and a pressure gauge to a charging hose and connect it to
the charging port.
(4) Activate the vacuum pump and vacuum the indoor unit and connection piping until
the pressure gauge becomes -100.7kPa (-755mmHg).
Evacuate from both the gas pipe and the liquid pipe.
(5) Continue evacuating the system for 1 hour after the pressure gauge reads -100.7kPa
(-755mmHg).
(6) Remove the charging hose and reinstall the charging cap.
CAUTION
Do not turn on the power unless all operations are complete.
After evacuating the system, add refrigerant.
Do not charge the system with a refrigerant other than R410A.
Always keep to the limit on the total amount of refrigerant. Exceeding the limit on the
total amount of refrigerant will lead to malfunction during charging of refrigerant.
Do not reuse recovered refrigerant.
Use an electronic scale to measure the charging amount of refrigerant.
Adding more refrigerant than the specified amount will cause a malfunction.
Charge refrigerant using the liquid pipe.
Adding refrigerant through the gas pipe will cause a malfunction.
Add refrigerant by charging the system with the refrigerant in the liquid state. If the
refrigerant cylinder is equipped with a siphon, it is not necessary to place the cylinder
upright.
Check if the steel cylinder has a siphon installed or not before filling. (There is an indica-
tion “with siphon for filling liquid” on the steel cylinder.)
Filling method
for cylinder with
siphon
Liquid
Gas
R410A
Set the cylinder vertical and fill with
the liquid.
(Liquid can be filled without turning
bottom up with the siphon inside.)
Filling method for
other cylinders
Liquid
Gas
R410A
Turn bottom up and fill with liquid.
(Be careful to avoid turning over the
cylinder.)
Be sure to use the special tools for R410A for pressure resistance and to avoid mixing
of impure substances.
If the units are further apart than the maximum pipe length, correct operation cannot be
guaranteed.
Make sure to back closing valve after refrigerant charging. Otherwise, the compressor
may fail.
Minimize refrigerant release to the air. Excessive release is prohibited under the Freon
Collection and Destruction Law.
8.2.2 Procedure for charging the system with refrigerant
(1) Remove the charging cap from the liquid pipe. Use standard refrigeration practices
when charging refrigerant.
(2) Attach a charging hose to the refrigerant cylinder, and connect it to the charging port.
(3) Add refrigerant by calculating the additional refrigerant volume in accordance with
the calculation formula indicated below.
(4) Remove the charging cap and install the charging hose.
(5) Remove the body caps (suction gas pipe, discharge gas pipe and liquid pipe), and
open the valves.
(6) Close the body caps.
(7) After adding refrigerant, indicate the added charging volume on the unit.
NOTES:
• Tighten the body caps and charging caps to the torque values specified in the Table A.
To open and close the valves, Use an M4 hexagon wrench for liquid pipe.
Use an M8 hexagon wrench for suction gas pipe and discharge gas pipe.
• If you cannot charge the specified amount of refrigerant with the above method, be
sure to charge the refrigerant through the gas pipe while operating in cooling mode. In
order to prevent liquid back-flow, carefully operate the refrigerant cylinder valve so that
the refrigerant will flow in certain part at a time.
8.2.3 Checking total amount of refrigerant and calculating the
amount of refrigerant charge to be added
• The amount of refrigerant charge to be added is the total value of the basic refrigerant
charge amount and the value calculated from the length of the liquid pipe.
• Round up the value to 2 decimal places.
Model HP
d
Factory charged amount
(kg)
a
Additional amount for out-
door unit (kg)
AJ*072LALDH 8 11.70 0
AJ*090LALDH 10 11.70 0
AJ*108LALDH 12 11.80 3.30
AJ*126LALDH 14 11.80 3.30
AJ*144LALDH 16 11.80 3.30
Diameter of liquid pipe (mm)
b
Additional amount for pipe length (kg/m)
Ø6.35 0.021
Ø9.52 0.058
Ø12.70 0.114
Ø15.88 0.178
Ø19.05 0.268
(1) Calculation of additional amount for pipe length.
A =
a
Outdoor unit 1 additional
amount for outdoor unit
+
a
Outdoor unit 2 additional
amount for outdoor unit
+
a
Outdoor unit 3 additional
amount for outdoor unit
kg kg kg
=
Total
kg
(2) Calculation of additional amount for pipe length.
B =
Total length of
ø 19.05 mm
liquid pipe
b ×
0.268
(kg/m)
+
Total length of
ø 15.88 mm
liquid pipe
b ×
0.178
(kg/m)
+
Total length of
ø 12.70 mm
liquid pipe
b ×
0.114
(kg/m)
mmm
kg kg kg
+
Total length
of ø 9.52 mm
liquid pipe
b ×
0.058
(kg/m)
=
Total length
of ø 6.35 mm
liquid pipe
b ×
0.021
(kg/m)
+
Total
mm
kg kg kg
(3) Calculation of additional charge refrigerant.
C = A+B =
kg
(Round up C to 2 decimal place)
(4) Calculation of factory charged amount.
A =
d
Outdoor unit 1 factory
charged amount
+
d
Outdoor unit 2 factory
charged amount
+
d
Outdoor unit 3 factory
charged amount
kg kg kg
=
Total
kg
(5) Total refrigerant amount check.
E = C+D =
kg
Check the total refrigerant amount under the following conditions.
Condition Computational formula
For 1 outdoor unit per refrigerant system:
Total amount of refrigerant ≤ 31.5 kg
E ≤ 31.5 kg
For 2 outdoor units per refrigerant system:
Total amount of refrigerant ≤ 63 kg
E ≤ 63 kg
For 3 outdoor units per refrigerant system:
Total amount of refrigerant ≤ 94.5 kg
E ≤ 94.5 kg
9378945708-02_IM_L9.indb 209378945708-02_IM_L9.indb 20 2022/1/20 15:34:392022/1/20 15:34:39
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