Hitachi FSXN Series Service Manual page 54

3 Piping work and
refrigerant charge
4. Pipe diameter between multikit and indoor unit
HP indoor unit
(0.8-1.5)
2.0 ø15.88
(2.5-5.0) ø15.88
Pipe working conditions
Part
Total pipe length
Current length
Maximum pipe length
Equivalent length
Maximum pipe length between the multikit of the first branch
and each indoor unit
Maximum pipe length between each multikit and each
indoor unit
Pipe length between connection kit 1 and each outdoor unit
Highest outdoor unit
Difference in height between
outdoor and indoor units
Lowest outdoor unit
Difference in height between indoor units
Difference in height between outdoor units
N O T E
(1)
• The connection kit is taken into account from the side of the indoor unit (as connection kit 1).
(2)
• When the maximum equivalent refrigerant pipe length (L1) from the outdoor unit/connection kit 1 to the
indoor unit is greater than 100 m, the diameter of the gas/liquid pipe from the outdoor unit/connection kit 1 to
the first branch must be increased using the reducer (field-supplied).
(3)
• Where the refrigerant pipe length is greater than 100 m, the pipe diameter does not have to be increased after
the first branch. Where the size of the multikit is greater than that of the first branch, adjust the size of the
multikit to the first branch. Where the diameter of the pipe selected after the first branch is greater than the
diameter of the pipe after it, use the same diameter as the inlet pipe.
(4)
• The pipe diameter -4- must be the same as that of the indoor unit connection.
(5)
• Where the liquid pipe length is greater than 15 m, use 9.53 mm diameter pipe and a reducer (field-supplied).
(6)
• Keep a direct distance of 500 mm or greater after the connection kit.
(7)
• The installation conditions for the refrigerant pipes are different depending on the number of indoor units
connected.
(8)
• The total pipe length permitted must be less than 1000 m due to the maximum additional refrigerant charge
limitation.
N O T E
1 Check that the gas pipe and the liquid pipe are equivalent in terms of length and installation system.
2 Use the multikit system for branching of the indoor units and the CH unit.
3 Install the indoor unit and the multikit according to the instructions given in this manual.
4 Where the length of pipe L3 between each multikit and each indoor unit is considerably longer than on another
indoor unit, the refrigerant will not flow correctly and performance is lower in comparison with other models
(recommended pipe length: up to 15 m).
47
SMGB0065 rev. 1 - 12/2010
(4)
.
Gas Liquid
(5)
ø12.7 ø6.35
(5)
ø6.35
ø9.53
Current total liquid pipe
HP indoor unit
8.0
10.0
—
Make
≤ Recommended number
of connected indoor units
≤ 1000 m
length
≤ 165 m
L1
≤ 190 m
≤ 90 m
L2
≤ 40 m
L3
≤ 10 m
L5
≤ 50 m
H1
≤ 40 m
≤ 15 m
H2
≤ 0.1 m
H5
Gas Liquid
ø19.05 ø9.53
ø22.2 ø9.53
— —
(7)
Permitted pipe length
≥ Recommended number
of connected indoor units
≤ 300 m
(8)
≤ 165 m
≤ 190 m
≤ 40 m
≤ 30 m
≤ 10 m
≤ 50 m
≤ 40 m
≤ 15 m
≤ 0.1 m
3