17
3
Refrigerant piping design
3-2. Allowable length / height difference of refrigerant piping
*1 Furthest indoor unit from 1st branch to be named "A"
Allowable value
Piping section
Pipe Length
Total extension of pipe (Liquid pipe, real length)
90 m
L1 + L2 + L3 + a + b + c + d + e + f
Furthest piping length
L
(*1)
Real length
50 m
L1 + L3 + f
Equivalent length
60 m
Max. real length of main pipe
30 m
L1
Max. real length of furthest piping from 1st branching Li (*1)
20 m
L3 + f
Max. real length of indoor unit connecting pipe
10 m
a, b, c, d, e, f
Height
Difference
Height between indoor and outdoor units
H1
Upper outdoor unit
15 m
―
Lower outdoor unit
15 m
―
Height between indoor units H2
10 m
―
f
a
b
c
d
A
*1
L3
L1
L2
e
Outdoor unit
Height difference
between indoor and
outdoor units H1
Main
pipe
1st branching
section
Branching pipe
Branching
header
Indoor unit
Y-shaped
branching joint
Branching pipe
Equivalent length corresponded to farthest piping L
Equivalent length corresponded to farthest piping after 1st branching Li
Height
difference
between indoor
units H2
