Additional Refrigerant Charge Calculation - Hitachi Set Free mini-HNRQ1 Series Installation & Maintenance Manual

4.7 Additional Refrigerant Charge Calculation

Although this unit has been charged with 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
RAS-
pipes
3.0~6.5
HNBRKQ1
For the Indoor units
For the refrigerant
pipes
RAS-
7.0~12
HNBRMQ1
For the 4-Way
cassette indoor
units
For the other indoor
units
NOTE:
Ensure the total additional charge should not be exceeded 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:
W is outdoor unit refrigerant charge before shipment.
0
(4) Record of Additional Charge
The total refrigerant charge of the system should be calculated by the following formula:
Total of Refrigerant Charge
The system
Liquid pipe
Symbol
diameter
Φ6.35 W11=
Φ9.52 W12=
Φ12.7 W13=
Liquid pipe
Symbol
diameter
Φ6.35 W11=
Φ9.52 W12=
Φ12.7 W13=
Model Symbol
RCI-1.0~1.5 W21=
RCI-2.0~2.5 W22=
RCI-3.0~6.5 W23=
RAS-3.0~ RAS-4.0~
3.5HNBRKQ1 5.0HNBRKQ1
3.9
Outdoor Unit
RAS-3.0~3.5HNBRKQ1
RAS-4.0~5.0HNBRKQ1
RAS-6.0~6.5HNBRKQ1
RAS-7.0~8.0HNBRMQ1
RAS-10~12HNBRMQ1
= W + W
0
= +
29
Contents
Total length of
Refrigerant
liquid piping
charge per meter
(m)
×0.020kg/m=
×0.050kg/m=
×0.085kg/m=
0
Total length of
Refrigerant
liquid piping
charge per meter
(m)
×0.020kg/m=
×0.059kg/m=
×0.120kg/m=
Numbers Refrigerant
(Q'ty) charge per unit
×0.23kg/pcs=
×0.29kg/pcs=
×0.47kg/pcs=
0
RAS-6.0~
6.5HNBRKQ1
7.9 8.6
W (kg)
0
3.0
4.1
4.4
5.5
6.5
= kg
Total Additional
Charge
Additional
charge
(kg)
W=W11+W12
+W13
Additional
charge
(kg)
W=W11+W12
Additional
+W13+W21
charge
+W22+W23
(kg)
RAS-7.0~ RAS-10~
8.0HNBRMQ1 12HNBRMQ1
12.9 12.9