Hitachi Set Free mini-HNRQ1 Series, Service Manual

Page: 35 / 187

28
INSTALLATION
3.7 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 Contents
Total Additional
Charge
RAS-3.0~6.5
HNBRKQ1
For the
refrigerant pipes
Pipe diameter Symbol
Total length of
liquid piping
(meter)
Refrigerant
charge per meter
Additional
charge
(kg)
W=W11+W12
+W13
Φ6.35 W11= ×0.020kg/m=
Φ9.52 W12= ×0.050kg/m=
Φ12.7 W13= ×0.085kg/m=
For the Indoor
units
0
RAS-7.0~12
HNBRMQ1
For the
refrigerant pipes
Pipe diameter Symbol
Total length of
liquid piping
(meter)
Refrigerant
charge per meter
Additional
charge
(kg)
W=W11+W12
+W13+W21
+W22+W23
Φ6.35 W11= ×0.020kg/m=
Φ9.52 W12= ×0.059kg/m=
Φ12.7 W13= ×0.120kg/m=
For the 4-way
cassette indoor
units
Model Symbol
Numbers
(Q’ty)
Refrigerant
charge per unit
Additional
charge
(kg)
RCI-1.0~1.5 W21= ×0.23kg/pcs=
RCI-2.0~2.5 W22= ×0.29kg/pcs=
RCI-3.0~6.5 W23= ×0.47kg/pcs=
For the other
indoor units
0
Note:
Ensure the total additional charge should not be exceeded the max. additional refrigerant charge quantity.
(2) Max. Additional Refrigerant Charge Quantity
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
Max. Additional Refrigerant Charge
Quantity (kg)
3.9 7.9 8.6 12.9 12.9
(3) Refrigerant Charge Amount of Outdoor Unit before Shipment.
Outdoor Unit W
0
(kg)
RAS-3.0~3.5HNBRKQ1 3.0
RAS-4.0~5.0HNBRKQ1 4.1
RAS-6.0~6.5HNBRKQ1 4.4
RAS-7.0~8.0HNBRMQ1 5.5
RAS-10~12HNBRMQ1 6.5
Note:
W
0
is outdoor unit refrigerant charge before shipment.