Mitsubishi Electric PUMY-P112VKM4 Technical & Service Manual page 144

10-2. REFRIGERANT PIPING SYSTEM (WHEN USING BRANCH BOX)
Branch box Method
Connection Examples
(Connecting to 8 Indoor Units)
Total piping length
Farthest piping length (L)
Permissible
length Piping length between outdoor unit and branch boxes
(One-way)
Farthest piping length after branch box (I)
Total piping length between branch boxes and indoor units
In indoor/outdoor section (H) *1
Permissible
height
In branch box/indoor unit section (h1)
difference
In each branch unit (h2)
(One-way)
In each indoor unit (h3)
Number of bends
*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)
(2) Sections From Branch box
to Indoor Unit (a to h)
Select the size from the table to the
right.
■ 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.
OCH673D
H H
(1) Refrigerant Piping Diameter In Section From Outdoor Unit to Branch box (Outdoor Unit Piping Diameter)
Model
PUMY-P112 Liquid Line
Each
PUMY-P125
Section of
Gas Line
PUMY-P140
Piping
(2) Refrigerant Piping Diameter In Section From Branch box to Indoor Unit (Indoor Unit Piping Diameter)
Indoor unit series
M series or
S series
P series
<Additional Charge>
Calculation of refrigerant charge
Pipe size Liquid pipe
ø6.35
+
(m) × 19.0 (g/m)
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
19.0 50.0
40 × + 45 ×
1000 1000
A
L
A
C
B
B
C h2 h2
h1
a b c d e
D
D D D
D
h3
A + B + C + a + b + c + d + e + f + g + h [ 150 m
A + C + h [ 80 m
A + B + C [ 55 m
l [ 25m
a + b + c + d + e + f + g + h [ 95 m
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)
h1 + h2 [15 m
h2 [ 15 m
h3 [ 12 m
[ 15
Piping Diameter (mm)
ø9.52
ø15.88
Model number A Liquid pipe (mm)
– 42
50 ø6.35
60
71 – ø9.52
– 50 ø6.35
60 – ø9.52
Total capacity of connected indoor units
Pipe size Liquid pipe
ø9.52
+
(m) × 50.0 (g/m)
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
+ 3.0 = 6.1kg (rounded up)
144
AOutdoor unit
BBranching joint
CBranch box
DIndoor unit
C
l
f g h
D
D
D
B Gas pipe (mm)
ø9.52
ø12.7
ø15.88
ø15.88
ø12.7
ø15.88
Amount for the indoor units
– 8.0 kW
8.1 – 16.0 kW
16.1 kW –
At the conditions
below:
1.5 kg
2.5 kg
3.0 kg