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7.3 Additional Refrigerant Charge Calculation
< Heat Pump >
Additional Refrigerant Charge Calculation
Although refrigerant has been charged into this unit in advance, additional refrigerant charge is required according to piping length.
Determine the additional refrigerant quantity according to the following procedure, and charge the system with it.
Record the additional refrigerant quantity to facilitate maintenance and servicing activities thereafter.
(1) Calculating Method of Additional Refrigerant Charge (W kg)
No. Symbol
1
W1
Additional Refrigerant Charge Calculation for Liquid Piping (W1 kg)
Pipe Diameter (mm)
φ28.58
φ25.4
φ22.2
φ19.05
φ15.88
φ12.7
φ9.52
φ6.35
NOTE:
Round off the numbers two decimal places.
2
W2
Additional Refrigerant Charge Calculation for Indoor Unit (W2 kg)
The additional refrigerant charge is required depending on the number of connected indoor units
and ratio of indoor unit connection capacity (Indoor Unit Total Capacity / Outdoor Unit Capacity).
Additional Refrigerant Charge Quantity (kg)
NOTE:
1. The table above shows the quantity of additional refrigerant charge per indoor unit.
e.g. 12 indoor units of 1.5 HP are connected and I.U. Capacity Ratio is 95% or more.
0.5kg/unit × 12 unit ＝ 6.0kg
2. The quantity of additional refrigerant based on the above calculation must not be exceed the following formula.
Maximum additional refrigerant charge = ("Total Indoor Unit Capacity (HP)" × 0.112)kg or 13.2kg whichever is bigger.
(Round off the numbers two decimal places.)
3
W3
The additional refrigerant charge is required depending on the number of connected outdoor units. (P1 kg)
Select adequate refrigerant charge from the table below.
Outdoor Unit Capacity (HP)
RAS-*HNCCLW
NOTE:
The table above shows the quantity of additional refrigerant charge per outdoor unit.
e.g. RAS-480HNCCLW is 2 outdoor unit of 24HP connected.
0.8kg/unit × 2 unit ＝ 1.6kg
4
W
NOTES:
1. Some refrigerant charge calculations differ when installing Indoor Unit with expansion valve kit.
2. Ensure that the total additional refrigerant charge quantity (W) should not exceed the max. additional refrigerant charge quantity shown in the table below "Table (※)".
(2) Charging Work
Charge the system with refrigerant R410A according to
"Installation Manual".
(3) Recording of Additional Refrigerant Charge
Total refrigerant charge of this system is calculated in
the following formula.
Total Ref. Charg =
W
This System
=
Total Additional Ref. Charge:
Total Ref. Charge:
Date of Ref. Charge Work:
※Attach this label on the service cover of the outdoor unit
after recording the calculation result in the blank above.
NOTES:
・W0 is outdoor unit Ref. charge before shipment.
・In case of the combination of the base units, calculate the total
ref. charge before shipment of the outdoor units to be combined.
A16381Z84L-rev.1
Table 7.1 Additional Refrigerant Charge Calculation
Total Piping Length (m)
Total Additional Ref. Charge For Liquid Piping
Indoor Unit Capacity (HP)
0.6-1.3
1.5-2.0
2.3-3.3
4.0-6.0
8.0-12.0
16.0
20.0
Additional Charge Ref. (kg)/unit
24
26
0.8
1.8
+
W0
+
=
kg
W
kg
kg
/
/
7. Air-Tight Test and Additional Refrigerant Charge
Contents
Refrigerant Amount for 1m Pipe (kg/m)
×0.67＝
×0.52＝
×0.36＝
×0.26＝
×0.17＝
×0.11＝
×0.056＝
×0.024＝
Additional Charge Ref. (kg)/unit
I.U. Capacity Ratio is less than 95%
0.0
0.0
0.0
0.0
0.0
0.0
0.0
28
1.8
Table(※) < Max. Additional Refrigerant Charge Quantity >
Outdoor Unit
8,10
12
14-18
Capacity (HP)
RAS-*HNCBLW
28.0
36.0
RAS-*HNCCLW
28.0
36.0
< Ref. Charge Amount of O.U Before Shipment (W0) kg >
W0 Outdoor Unit Ref. Charge (kg)
Outdoor Unit
8, 10
12
Capacity (HP)
RAS-*HNCBLW
8.3
9.3
RAS-*HNCCLW
5.6
8.3
Additional Ref. Charge (kg)
I.U. Capacity Ratio is 95% or more
0.3
0.5
0.9
1.1
1.4
1.5
2.0
Calculation of Additional Ref. Charge (W1 + W2 + W3)=
Max. Additional Ref. Charge (kg)
20-24
26, 28
30-42
44-66
68-88
40.0
51.0
63.0
63.0
63.0
73.0
40.0
46.0
56.0
56.5
63.0
73.0
14, 16
18
20, 22 24-28
10.3
11.1
11.1
-
8.9
10.2
11.2
11.5
Additional
Ref. Charge
kg
kg
kg
kg
90-112
-
93.0
88
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