Hitachi FSG Series, Technical Catalogue

Page: 278 / 424

13
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REFRIGERANT PIPING AND REFRIGERANT CHARGE
13.1. REFRIGERANT PIPING SELECTION
Set-Free system is designed considering be available in all
installation cases. Therefore, HITACHI is using two different
refrigerant pipe distributors:
Line Branch system and Header Branch system.
Both systems are available for two pipes system (FSG(1))
and three pipes system (FXG(1)) as indicated below.
13.1.1. REFRIGERANT PIPING WORK RANGE
The piping selection and distribution must be designed
considering the following specifications:
$
WARNING:
The liquid piping and the gas piping must be the same
piping length and run along the same route.
Install multi-Kits (Optional Accessory as system parts)
must be used for the branch pipe to the indoor unit.
Install multi-Kits as the same horizontal level.
Oil trap every H
t
of height difference for gas piping
between indoor unit and outdoor unit is required when
Outdoor Unit is located higher than the Indoor Units.
However, in case that the Outdoor Unit is located
lower than Indoor Unit, it is not required to put oil trap
in the suction gas piping, since the oil in the system
can return to the compressor due to the oil return
control system.
n
Two Pipes System (FSG/FSG1)
Applicable Range
FSG/FSG1 ITEM
5~20HP 24~30HP
Actual
£
100
£
120
Length between O.U. and
farthest I.U. (L)
Equivalent
£
125
£
150
Piping length from first branch to each I.U.
£
30
£
40
Total length from 1
st
Multi-kit to all I.U. Li -
£
480
Piping length from each Multi-Kit to I.U. (*)
£
30
£
30
Height difference (Hi-o) between O.U. to I.U.
(O.U. over I.U. / O.U. lower I.U.)
£
50/
£
40
£
50/
£
40
Height difference (Hi) between I.Us.
£
15
£
15
Oil Trap Height (Ht)
£
25
£
10
(*) See Item 13.1.3 for more details
See Table (*)
Trap (Refrigerant Piping at Gas Side)
Make a trap according to height difference
(Ht) between indoor unit and outdoor unit (see
table).
Outdoor Unit
Li
Hi
Indoor Units
Install
multi-Kits
horizontally
Hi-o
L