Mitsubishi Electric MXZ-SM36NAM2 Technical & Service Manual page 142

10-1-2. MXZ-SM60NAM2-U1
Line-Branch Method
Connection Examples
(Connecting to 4 Indoor Units)
Total Piping Length
Permissible
Farthest Piping Length
Length
Farthest Piping Length After First Branch
High/Low Difference in Indoor/Outdoor Section
Permissible High/
Low Difference
High/Low Difference in Indoor/Indoor Section
■
Selecting the Refrigerant Branch Kit
■
Select Each Section of Refrigerant Piping
(1) Section From Outdoor Unit
to First Branch (A)
(2) Sections From Branch to
Indoor Unit (a,b,c,d)
(3) Section From Branch to
Branch (B,C)
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 0.2 lb [0.1 kg], round up the calculated
additional refrigerant charge.
(For example, if the calculated charge is 13.2 lb [6.01 kg], round up
the charge to 13.4 lb [6.1 kg].)
・ The amount of additional refrigerant for MXZ-SM60 which is
calculated from the total capacity of indoor units and the
combination of extended pipes must not be over 28.4 lb[12.9kg].
OCH810A
A
B
A+B+C+a+b+c+d ≤ 492 ft [150 m]
(L)
A+B+C+d ≤ 262 ft [80 m]
( ) ℓ
B+C+d ≤ 98 ft [30 m]
(H)
164 ft [50 m] (If the outdoor unit is lower, 131 ft [40 m])
(h)
49 ft [15 m]
Use an optional branch piping kit (CMY-Y62-G-E).
(1) Refrigerant Piping Diameter In Section
From Outdoor Unit to First Branch
(Outdoor Unit Piping Diameter)
Model
Each
Section of MXZ-SM60
Piping
(3) Refrigerant Piping Diameter In Section
From Branch to Branch
Liquid Line (inch[mm]) Gas Line (inch[mm])
3/8 [ø9.52]
<Additional Charge>
Calculation of refrigerant charge
Pipe size
Liquid pipe
ø6.35
[ft] × 0.29 [oz/ft]
(m) × 27.0 (g/m)
Included refrigerant amount when shipped from the factory
Included refrigerant amount
11 LBS. 4 OZ. (5.1 kg)
<Example>
Outdoor model : P60
Indoor 1 : P24 (24 kBtu/h)
2 : P15 (15 kBtu/h)
3 : P08 (8 kBtu/h)
4 : P06 (6 kBtu/h)
The total length of each liquid line is as follows:
[3/8"] ø9.52 : A + B + C + a = 20 + 5 + 5 + 15 = 147 ft [45 m]
[1/4"] ø6.35 : b + c + d = 10 + 10 + 20 = 132 ft [40 m]
The total capacity of connected indoor unit is as follows:
24 + 15 + 08 + 06 = 53
<Calculation example>
Additional refrigerant charge
132 ft × 0.29 oz + 147 ft × 0.75 oz + 88 oz = 237 oz
A
L
ℓ
B C
a b c
C
C C
(2) Refrigerant Piping Diameter In Section
Piping Diameter (inch[mm])
Liquid Line 3/8 [ø9.52]
Gas Line 3/4 [ø19.05]
3/4 [ø19.05]
Total capacity of
Pipe size
connected indoor units
Liquid pipe
+
+
– 27 kBtu/h
ø9.52
28 – 54 kBtu/h
[ft] × 0.75 [oz/ft]
(m) × 70.0 (g/m)
55 – 78 kBtu/h
A : ø9.52 66 ft [20 m]
B : ø9.52 16 ft [5 m]
C : ø9.52 16 ft [5 m]
a : ø9.52 49 ft [15 m]
b : ø6.35 33 ft [10 m]
c : ø6.35 33 ft [10 m]
d : ø6.35 66 ft [20 m]
[
40 ×
142
d
C
A Outdoor Unit
B First Branch
C Indoor unit
From Branch to Indoor Unit
(Indoor Unit Piping Diameter)
Model number Piping Diameter (inch[mm])
Liquid Line 1/4 [ø6.35]
18 or lower
Gas Line 1/2 [ø12.7]
Liquid Line 3/8 [ø9.52]
24 o54
Gas Line 5/8 [ø15.88]
Liquid Line 3/8 [ø9.52]
72
Gas Line 3/4 [ø19.05]
Amount for the
indoor units
53 oz (1.5 kg)
88 oz (2.5 kg)
106 oz (3.0 kg)
At the conditions
below:
27.0 70.0
+ 45 × + 2.5 = 6.8 kg (rounded up)
1000 1000
]