Mitsubishi Electric PUMY-P112VKM3 Technical & Service Manual page 142

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
Piping length between outdoor unit and branch boxes
length
(One-way)
Farthest piping length after branch box (I)
Total piping length between branch boxes and indoor units
In indoor/outdoor section (H)*
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.
OCH632A
A
A
B
H H
h1
h3
1
(1) Refrigerant Piping Diameter In Section From Outdoor Unit to Branch box (Outdoor Unit Piping Diameter)
Model
PUMY-P112
Each
PUMY-P125
Section of
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
40 ×
1000
L
C
B
C h2 h2
b
a c d e f
D
D
D D D
D
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 case of that outdoor unit is set higher than indoor unit)
H ≦ 40 m (In 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)
Liquid Line
{9.52
Gas Line
{15.88
Model number A Liquid pipe
15 to 42
{6.35
50
{6.35
60
{6.35
71
{9.52
35,50
{6.35
60 to 100
{9.52
Total capacity of
Pipe size
connected indoor units
Liquid pipe
+ +
up to 8.0 kW
ø9.52
8.1 to 16.0 kW
(m) × 50.0 (g/m)
16.1 kW or above
A : ø9.52 30 m
a : ø9.52 15 m
b : ø6.35 10 m
c : ø6.35 10 m
d : ø6.35 20 m
50.0
+ 45 × + 3.0 = 6.1 kg (rounded up)
1000
142
AOutdoor unit
BBranching joint
CBranch box
DIndoor unit
C
l
g h
D
D
B Gas pipe
{9.52
{12.7
{15.88
{15.88
{12.7
{15.88
Amount for the
indoor units
1.5 kg
2.5 kg
3.0 kg
At the conditions
below: