9 Piping work and refrigerant charge
Refrigerant charge amount
TCGB0136 rev.1 - 05/2021
92
9.4 Refrigerant charge amount
Although refrigerant has been charged into this unit, additional refrigerant charge is required according to piping length.
•
The additional refrigerant quantity should be determined and charged into the system according to the following
procedure.
•
Record the additional refrigerant quantity in order to facilitate maintenance and servicing activities.
!
C A U T I O N
• When charging refrigerant, measure the amount precisely. Overloading or underloading of refrigerant may cause compressor
problems. If the actual piping length is less than 5 m consult your dealer.
•
Appropriate refrigerant
The refrigerant used in each unit is identified on the specification label and manuals of the unit. Hitachi shall not be held liable for any
failure, trouble, malfunction or accident caused by units illegally charged with refrigerants other than the specified one.
•
Consequences of charging non-specified refrigerant
• It may cause mechanical failure, malfunction and other accidents. It may cause operational failure of protection and safety devices of
air conditioners. It may also cause lubrication failure of the sliding part of the compressor due to deterioration of refrigerant oil.
• In particular, hydrocarbon refrigerants (such as propane, R441A, R443A, GF-08, etc.) are not allowed, since these are combustible
and may cause major accidents such as fire and explosion in case of improper handling.
• Once a non-specified refrigerant has been charged, no further servicing (including draining of refrigerant) shall be performed, even
in case of malfunction. Improper handling of refrigerant may be a cause of fire and explosion, and servicing in such cases may be
considered an illegal act.
• End clients and costumers shall be informed that servicing is not approved, and the installer who charged the non-specified refrigerant
shall be asked to fix the unit.
9.4.1 Refrigerant charge before shipment (W
0
(kg))
W
0
is the outdoor unit refrigerant charge before shipment explained before, and it’s shown in the following table:
UTOPIA series 2
Model
Refrigerant charge before
shipment (W
0
(kg))
Additional refrigerant charge
(P) (g/m)
Maximum additional charge
(kg)
RAS-3HVNC1
1.9
40
1.2
RAS-4HVR(C/P)2E
3.0
45
2.9
RAS-5HVR(C/P)2E
RAS-6HVR(C/P)2E
RAS-4HR(C/P)2E
RAS-5HR(C/P)2E
RAS-6HR(C/P)2E
RAS-4HVN(C/P)2E
3.2
60
3.9
RAS-5HVN(C/P)2E
RAS-6HVN(C/P)2E
RAS-4HN(C/P)2E
RAS-5HN(C/P)2E
RAS-6HN(C/P)2E
9.4.2 Calculation method for the additional refrigerant charge
Calculate the additional refrigerant charge amount according to the following steps:
Step 1: Additional refrigerant charge calculation for liquid piping (W
1
(kg))
Outdoor units have been charged with refrigerant for 20 m of actual piping length: In systems with longer actual piping
length, an additional refrigerant charge is required.
Use the following formula:
W
1
=
(L-20)
x
P
L: Total piping length (m)
P: Additional refrigerant charge (kg/m) (Refer to the
