En-24
8. 3. Additional charging
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 specifi ed 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.
8. 3. 1. Procedure for charging the system with refrigerant
1) Remove the charging cap from the liquid pipe. Use standard refrigeration prac-
tices 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.
* Tighten the body caps and charging caps to the torque values specifi ed 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 can not charge the specifi ed amount of refrigerant with the above
method, be sure to charge the refrigerant through the gas pipe while operat-
ing in cooling mode. In order to prevent liquid back-fl ow, carefully operate
the refrigerant cylinder valve so that the refrigerant will fl ow in certain part at
a time.
8. 3. 2. 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 refrig-
erant charge amount and the value calculated from the length of the liquid pipe.
• Round up the value to 2 decimal places.
Model Ton
d
Factory charged
amount [lbs (kg)]
a
Additional amount for
outdoor unit [lbs (kg)]
AOUA72TLBV 6 26.01 (11.80) 6.61 (3.00)
AOUA96TLBV 8 26.01 (11.80) 6.61 (3.00)
AOUA120TLBV 10 26.01 (11.80) 14.99 (6.80)
Diameter of liquid pipe
[in (mm)]
b
Additional amount for pipe length
[lbs/ft (kg/m)]
1/4 (6.35) 0.014 (0.021)
3/8 (9.52) 0.039 (0.058)
1/2 (12.70) 0.077 (0.114)
5/8 (15.88) 0.120 (0.178)
3/4 (19.05) 0.180 (0.268)
(1) Calculation of additional amount for outdoor unit
A =
a
Outdoor unit1 additional
amount for outdoor unit
lbs (kg)
+
a
Outdoor unit2 additional
amount for outdoor unit
lbs (kg)
+
a
Outdoor unit3 additional
amount for outdoor unit
lbs (kg)
=
Total
lbs (kg)
(2) Calculation of additional amount for pipe length
B =
Total length of
ø 3/4 in
(19.05 mm)
liquid pipe
b
× 0.180
(× 0.268)
[lbs/ft (kg/m)]
ft (m)
lbs (kg)
+
Total length of
ø 5/8 in
(15.88 mm)
liquid pipe
b
× 0.120
(× 0.178)
[lbs/ft (kg/m)]
ft (m)
lbs (kg)
+
Total length of
ø 1/2 in
(12.70 mm)
liquid pipe
b
× 0.077
(× 0.114)
[lbs/ft (kg/m)]
ft (m)
lbs (kg)
+
Total length of
ø 3/8 in
(9.52 mm)
liquid pipe
b
× 0.039
(× 0.058)
[lbs/ft (kg/m)]
ft (m)
lbs (kg)
+
Total length of
ø 1/4 in
(6.35 mm)
liquid pipe
b
× 0.014
(× 0.021)
[lbs/ft (kg/m)]
ft (m)
lbs (kg)
=
Total
lbs (kg)
(3) Calculation of additional charge refrigerant
C=A+B =
lbs (kg)
(Round up C to 2 decimal place)
(4) Calculation of factory charged amount
D =
d
Outdoor unit1
factory charged amount
lbs (kg)
+
d
Outdoor unit2
factory charged amount
lbs (kg)
+
d
Outdoor unit3
factory charged amount
lbs (kg)
=
Total
lbs (kg)
(5) Total refrigerant amount check
E=C+D=
lbs (kg)
NOTE:
Check the total refrigerant amount under the following conditions
Condition Computational formula
For 1 outdoor unit per refrigerant system
: Total amount of refrigerant 77.16 lbs (35.00 kg)
E ≤ 77.16 lbs (35.00 kg)
For 2 outdoor units per refrigerant system
: Total amount of refrigerant ≤ 154.32 lbs (70.00 kg)
E ≤ 154.32 lbs (70.00 kg)
For 3 outdoor units per refrigerant system
: Total amount of refrigerant ≤ 231.49 lbs (105.00 kg)
E ≤ 231.49 lbs (105.00 kg)
<Calculation>
• When there are 3 outdoor units (AOUA96TLBV, AOUA96TLBV, AOUA72TLBV)
connected to 1 system
(1) Calculation of additional amount for outdoor unit
A = 6.61 lbs + 6.61 lbs + 6.61 lbs = 19.83 lbs
(A = 3.00 (kg) + 3.00 (kg) + 3.00 (kg) = 9.00 (kg))
(2) Calculation of additional amount for pipe length
If liquid pipe piping length is the following
Ø3/4 in : 164 ft, Ø5/8 in : 82 ft, Ø1/2 in : 0 ft, Ø3/8 in : 65 ft, Ø1/4 in : 49 ft
(Ø19.05 mm : 50 m, Ø15.88 mm : 25 m, Ø12.70 mm : 0 m, Ø9.52 mm : 20 m, Ø6.53 mm : 15 m)
Additional charge volume
B = 164 ft × 0.180 lbs/ft + 82 ft × 0.120 lbs/ft + 0 ft × 0.077 lbs/ft
+ 65 ft × 0.039 lbs/ft + 49 ft × 0.014 lbs/ft
= 42.581 lbs
(B = 50 m × 0.268 kg/m + 25 m × 0.178 kg/m + 0 m × 0.114 kg/m
+ 20 m × 0.058 kg/m + 15 m × 0.021 kg/m
= 19.325 kg)
(3) Calculation of additional charge refrigerant
C = A + B = 19.83 lbs + 42.581 lbs = 62.411 lbs → 62.41 lbs
(C = A + B = 9.00 kg + 19.325 kg = 28.325 kg → 28.33 kg)
(4) Calculation of factory charged amount
D = 26.01 lbs + 26.01 lbs + 26.01 lbs = 78.03 lbs
(D = 11.80 kg + 11.80 kg + 11.80 kg = 35.40 kg)
(5) Check the total amount of refrigerant
When 3 outdoor units are connected to 1 system, the following condition must be
satisfi ed.
Condition: E = C + D ≤ 231.49 lbs (105.00 kg)
Calculation: 62.41 lbs+ 78.03 lbs = 140.44 < 231.49 lbs
(28.33 kg + 35.40 kg = 63.73 kg < 105.00 kg)
→ No problem if the above condition is satisfi ed.
9378945159-04_IM.indb 249378945159-04_IM.indb 24 2015/12/1 10:50:582015/12/1 10:50:58
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