12.3 Additional Refrigerant Charge Calculation
Table
12
.1 Additional Refrigerant Charge Calculation
No.
Symbol
Contents
Additional Charge (kg)
1
W1
Additional Refrigerant Charge Calculation for Liquid Piping (W1 kg)
Pipe Diameter Total Piping Length
(m)
Refrigerant Amount
for 1m Pipe
Additional Charge
(kg)
f
22.2
m
×0.39 =
f
19.05
m
×0.28 =
f
15.88
m
×0.19 =
f
12.7
m
×0.12 =
f
9.53
m
×0.06 =
f
6.35
m
×0.03 =
Total Additional Charge For Liquid Piping =
kg
2
W2
Additional Refrigerant Charge Calculation for Indoor Unit (W2 kg)
Additional refrigerant charge is 1kg/unit of 76kBtu/h and 96kBtu/h indoor unit.
Additional refrigerant charge of less than 76kBtu/h indoor units is not needed.
76 and 96 Total Indoor Unit Numbers Additional Charge
× 1.0kg/unit =
kg
3
W3
The Ratio of Indoor Unit Connection Capacity (Indoor Unit Total Capacity/
Outdoor Unit Capacity) Additional Charge
Determine the ratio of indoor unit connection capacity.
Condition
Refrigerant Amount
• I.U.Capacity Ratio is less than 100%
:
• I.U.Capacity Ratio is 100~115% :
• I.U.Capacity Ratio is 116~130% :
0.0kg
0.5kg
1.0kg
kg
4
W
Calculation of Additional Charge (W kg) =
W1 + W2 +W3
kg
Note:
Ensure that the total additional charge should not be exceeded the max. additional refrigerant charge quantity
as shown in the table below.
Although refrigerant has been charged into this unit, additional refrigerant charge is required according to
piping length.
Determine the additional refrigerant quantity according to the following procedure, and charge it into the system.
Record the additional refrigerant quantity to facilitate maintenance and servicing activities thereafter.
< Max. Additional Refrigerant Charge Quantity >
1. Calculating Method of Additional Refrigerant Charge (W kg)
Outdoor Unit (
k
Btu/ h)
76/96
Max. Additional Ref.
Charge Quantity (kg)
2. Charging Work
Charge refrigerant (R410A) into the system according to Item
12.4
.
3. Record of Additional Charge
Total refrigerant charge of this system is calculated in the following formula.
Total Ref. Charge = W + Wo
This System =
+
=
kg
Ref. Charge Amount of O.U. Before Shipment (W0) kg
76
96
114
10.5
136
10.5
154
10.5
Note:
• W0 is outdoor unit ref. charge before shipment.
• In case of the combination of the base unit, calculate the total
ref. charge before shipment of the outdoor units to be combined.
Total Additional Charge: W
kg
Total Ref. Charge:
kg
Date of Ref. Charge Work:
/
/
232~454
52.0
Outdoor Unit (
k
Btu/ h)
9.9
9.9
W0 Outdoor Unit Ref. Charge (kg)
114
136
154
170~212
33.0
38.5
38.5
42.0
46.0
125
