15
4.5
Refrigerant
Piping
Selection
Example
The
example
below
illustrates
the
piping
selection
procedure
for
a
system
consisting
of
three
outdoor
units
(22HP
+
12HP
+
12HP)
and
13
indoor
units.
The
system's
equivalent
total
piping
length
is
in
excess
of
90m;
the
piping
between
the
farthest
indoor
unit
and
the
first
indoor
branch
joint
is
less
than
40m
in
length;
and
each
indoor
auxiliary
pipe
(from
each
indoor
unit
to
its
nearest
branch
joint)
is
less
than
10m
in
length.
Figure
3
‐
4.4:
Refrigerant
piping
selection
example
Step
1:
Select
indoor
auxiliary
pipes
Indoor
units
N
1
to
N
5
,
N
7
to
N
9
and
N
11
to
N
13
are
of
capacity
5.6kW
or
greater
and
their
indoor
auxiliary
pipes
are
less
than
10m
in
length.
Refer
to
Table
3
‐
4.8.
Indoor
auxiliary
pipes
a
to
e,
g
to
i,
and
k
to
m
are
Φ
15.9
/
Φ
9.53.
Indoor
units
N
6
and
N
10
are
of
capacity
less
than
4.5kW
and
their
indoor
auxiliary
pipes
are
less
than
10m
in
length.
Refer
to
Table
3
‐
4.8.
Indoor
auxiliary
pipes
f
and
j
are
Φ
12.7
/
Φ
6.35.
Step
2:
Select
indoor
main
pipes
and
indoor
branch
joints
B
to
L
The
indoor
units
(N
2
and
N
3
)
downstream
of
indoor
branch
joint
D
have
total
capacity
of
14
+
7.1
=
21.1kW.
Refer
to
Table
3
‐
4.4.
Indoor
main
pipe
L
4
is
Φ
19.1
/
Φ
9.53.
Indoor
branch
joint
D
is
FQZHN
‐
01D.
The
indoor
units
(N
1
to
N
6
)
downstream
of
indoor
branch
joint
B
have
total
capacity
of
14
x
4
+
7.1
+
2.8
=
65.9kW.
Refer
to
Table
3
‐
4.4.
Indoor
main
pipe
L
2
is
Φ
28.6
/
Φ
15.9.
Indoor
branch
joint
B
is
FQZHN
‐
03D.
The
other
indoor
main
pipes
and
indoor
branch
joints
C
and
E
to
L
are
selected
in
the
same
fashion.
Step
3:
Select
main
pipe
and
indoor
branch
joint
A
The
indoor
units
(N
1
to
N
13
)
downstream
of
indoor
branch
joint
A
have
total
capacity
of
14
x
7
+
7.1
x
2
+
5.6
x
2
+
2.8
x
2
=
129kW.
The
system's
equivalent
total
piping
length
is
in
excess
of
90m.
The
total
capacity
of
the
outdoor
units
is
22
+
12
+
12
=
46HP.
Refer
to
Tables
3
‐
4.4
and
3
‐
4.5.
Main
pipe
L
1
is
the
larger
of
Φ
38.1
/
Φ
19.1
and
Φ
38.1
/
Φ
22.2,
hence
Φ
38.1
/
Φ
22.2.
Indoor
branch
joint
A
is
FQZHN
‐
04D.
Step
4:
Select
outdoor
connection
pipes
and
outdoor
branch
joints
The
master
unit
is
22HP
and
the
slave
units
are
12HP.
Refer
to
Table
3
‐
4.6.
Outdoor
connection
pipes
g1
and
g2
are
Φ25.4
/
Φ
12.7
and
outdoor
connection
pipe
g3
is
Φ
31.8
/
Φ
15.9.
Refer
to
Table
3
‐
4.6.
Outdoor
connection
pipe
G
1
is
Φ
38.1
/
Φ
19.1.
N
1
(140)
N
4
(140)
N
7
(140)
N
8
(140)
N
10
(28)
N
12
(56)
N
11
(140)
N
3
(71)
N
6
(28)
N
13
(56)
A
B
G
H
K
I
L
C
E
L
1
L
2
L
3
L
5
L
7
L
8
L
11
L
12
L
9
a
c
d
f
g
h
j
l
m
k
M
N
g1
g2
g3
G
1
12HP
12HP
22HP
D
N
2
(140)
b
L
4
N
5
(140)
F
L
6
e
N
9
(71)
i
J
L
10
First
indoor
branch
joint
Legend
L
1
Main
pipe
L
2
to
L
12
Indoor
main
pipes
a
to
m
Indoor
auxiliary
pipes
A
to
L
Indoor
branch
joints
M,
N
Outdoor
branch
joints
g1
to
g3,
G
1
Outdoor
connection
pipes
Figures
in
parentheses
indicate
indoor
unit
capacity
indexes.
