Additional Refrigerant Charge Calculation - Hitachi RAS-070HNBRMQ2 Manual

4.7 Additional Refrigerant Charge Calculation

Although this unit has been charged the refrigerant, additional refrigerant charge is required on the site.
Determine additional quantity of refrigerant required according to the following table, and charge it into the
system.
(1) Calculating the method of Additional Refrigerant Charge
Model Item
For the
refrigerant
070~120
pipes
For the
Indoor units
NOTE:
 Ensure the total additional charge should not exceed the max. additional refrigerant charge quantity.
(2) Max. Additional Refrigerant Charge Quantity
Outdoor Unit
Max. Additional Refrigerant
Charge Quantity (kg)
(3) Refrigerant Charge Amount of Outdoor Unit before Shipment.
NOTE:
 W0 is outdoor unit refrigerant charge before shipment.
(4) Record of Additional Charge
The total refrigerant charge of the system should be calculated in the following formula.
Total of Refrigerant Charge
The system
Pipe
Symbol
diameter
Φ6.35 W11=
Φ9.52 W12=
Φ12.7 W13=
070~120
13.5
Outdoor Unit
070~090
100
110~120
= +
W
= +
Contents
Total length of
liquid piping
(meter)
×0.03kg/m=
×0.07kg/m=
×0.12kg/m=
0
W
（kg）
0
5.6
7.0
9.0
W
0
=
kg
27
Refrigerant Additional
charge per
charge
meter (kg)
Total
Additional
Charge
W=W11+W12
+W13