Hitachi FSXN Series Service Manual page 55

3 Piping work and
refrigerant charge
Pipe branching restrictions
Follow the instructions given in the table below for pipe installation (field-supplied).
Maximum pipe length
between the multikit of the
first branch and each
indoor unit (L2)
≤ 40 m
From 41 m to 90 m
N O T E
(1)
Main pipe branch: distribution from one (1) multikit to two (2) multikits.
A: main branch
Figure 1: two branches on the main pipe
A
B
A: main branch
B: secondary branch
Figure 3: distributor used as branching for three pipes and
branching for two pipes
A
B
A: branch
B: distributor
48
SMGB0065 rev. 1 - 12/2010
Main pipe branch
Pipe length after the Number of main pipe
branch
a+b+c ≤ 30 m or d+e
+f ≤ 30 m
a+b+c > 30 m or d+e
+f > 30 m
— Up to 1 (Figure 1)
A
41 - 90 m
≤ 40 m
≤ 40 m
(1)
Capacity ratio of the
indoor units after the
main branch
branches
No limit
Up to 2
≥ 40% (Figure 2)
a b
c
B B
d e
f
B B
Figure 2: capacity ratio of the indoor units ≤ 40%
A
A: main branch
Figure 4: do not connect a branch to a distributor
B
A: branch
B: distributor
Branch and distributor
combination
— Available (Figures 3 and 4)
Not available
B: indoor units
41 - 90 m
20%
80%
A
A