130
OCH740
10-2. REFRIGERANT PIPING SYSTEM (WHEN USING BRANCH BOX)
Branch box Method
Connection Examples
(Connecting to 8 Indoor Units)
A
B
C
L
h2
H
A
Outdoor unit
B
Branching joint
C
Branch box
D
Indoor unit
a
b
d
c
e
f
g
h
h2
H
h1
h3
C
A
B
C
D
D
D
D
D
D
D
D
R
Permissible
length
(One-way)
Total piping length
A + B + C + a + b + c + d + e + f + g + h
[
150 m
Farthest piping length (L)
A + C + h
[
80 m
Piping length between outdoor unit and branch boxes A + B + C
[
55 m
Farthest piping length after branch box (
R
)
R
[
25m
Total piping length between branch boxes and indoor units
a + b + c + d + e + f + g + h
[
95 m
Permissible
height
difference
(One-way)
In indoor/outdoor section (H)*1
H
[
50 m (In the case of that outdoor unit is set higher than indoor unit)
H
[
40 m (In the case of that outdoor unit is set lower than indoor unit)
In branch box/indoor unit section (h1)
h1 + h2
[
15 m
In each branch unit (h2)
h2
[
15 m
In each indoor unit (h3)
h3
[
12 m
Number of bends
[
15
*1 Branch box should be placed within the level between the outdoor unit and indoor units.
■ Select Each Section of Refrigerant
Piping
(1) Section From Outdoor Unit
to Branch box (A, B, C)
Each
Section of
Piping
(2) Sections From Branch box
to Indoor Unit (a to h)
Select the size from the table to the
right.
(1) Refrigerant Piping Diameter In Section From Outdoor Unit to Branch box (Outdoor Unit Piping Diameter)
Model
Piping Diameter (mm)
P112
P125
P140
Liquid Line
ø9.52
Gas Line
ø15.88
(2) Refrigerant Piping Diameter In Section From Branch box to Indoor Unit (Indoor Unit Piping Diameter)
Indoor unit series Model number A Liquid pipe (mm) B Gas pipe (mm)
M series or
S series
15 to 42
ø6.35
ø9.52
50
ø6.35
ø12.7
60
ø6.35
ø15.88
71
ø9.52
ø15.88
P series
3
5,50
ø6.35
ø12.7
60 to 100
ø9.52
ø15.88
■ Additional refrigerant charge
Refrigerant for the extended piping is
not included in the outdoor unit when
the unit is shipped from the factory.
Therefore, charge each refrigerant piping
system with additional refrigerant at the
installation site. In addition, in order to
carry out service, enter the size and
length of each liquid pipe and additional
refrigerant charge amounts in
the spaces provided on the ˝Refrigerant
amount˝ plate on the outdoor unit.
Calculation of additional refrigerant
charge
• Calculate the additional charge using
the liquid pipe size and length of the
extended piping and total capacity of
connected indoor units.
• Calculate the additional refrigerant charge
using the procedure shown to the right,
and charge with the additional refrigerant.
• For amounts less than 0.1 kg, round
up the calculated additional refrigerant
charge.
(For example, if the calculated charge is
6.01 kg, round up the charge to 6.1 kg.)
• In the calculation for the additional
refrigerant charge, use 11.2 kW for the
cylinder unit or hydrobox.
<Additional Charge>
Calculation of refrigerant charge
Pipe size Liquid pipe
ø6.35
+
Pipe size Liquid pipe
ø9.52
+
Total capacity of connected indoor units Amount for the indoor units
– 8.0 kW
1.5 kg
(m) × 19.0 (g/m)
(m) × 50.0 (g/m)
8.1 – 16.0 kW
2.5 kg
16.1 kW –
3.0 kg
Included refrigerant amount when shipped from the factory
Included refrigerant amount
4.8 kg
<Example>
Outdoor model: P125
Indoor
1: P63 (7.1 kW)
2: P40 (4.5 kW)
3: P25 (2.8 kW)
4: P20 (2.2 kW)
The total length of each liquid line is as follows:
ø9.52: A + a = 30 + 15 = 45 m
ø6.35: b + c + d = 10 + 10 + 20 = 40 m
The total capacity of connected indoor unit is as follows:
7.1 + 4.5 + 2.8 + 2.2 = 16.6
<Calculation example>
Additional refrigerant charge
A: ø9.52 mm
30 m
a: ø9.52 mm
15 m
b: ø6.35 mm
10 m
c: ø6.35 mm
10 m
d: ø6.35 mm
20 m
At the conditions
below:
40 × + 45 × + 3.0 = 6.1kg (rounded up)
1000
1000
19.0
50.0
