11-3.Refrigerant Charging Calculation - Mitsubishi Electric SMART MULTI MXZ-SM36NAM2-U1 Data Book

11. PIPING DESIGN
11-3. Refrigerant charging calculation
11-3-1. MXZ-SM36, 48NAM2-U1/MXZ-SM36/42/48NAMHZ2-U1
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.
• Calculate the additional refrigerant charge using the procedure below, 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 10.92 kg, round up the charge to 11.0 kg.)
• When connecting a PAA-series unit(s), set additional constraints on the amount of additional refrigerant as follow.
Number of connecting PAA-･A
MXZ-SM36/42/48
Additional
refrigerant charge
=
(kg)
[oz]
Example:
MXZ-SM48NAM2-U1
P24
Additional
refrigerant charge
=
(kg)
=
=
Additional
refrigerant charge
=
(oz)
=
=
M-P0890
1 unit 2 units
7.7 kg 271 oz 6.7 kg 236 oz
Pipe size Pipe size
ø
Liquid pipe 6.35 Liquid pipe
+
(m) x 0.019 (kg/m) (m) x 0.05 (kg/m)
0.21 [oz/ft.]
Indoor 1: P24
Indoor 2: P15
Indoor 3: P08
Indoor 4: P08
Total length of each liquid pipe is as follows
A ( 30 m [98 ft.] )
a ( 15 m [49 ft.] )
b ( 10 m [33 ft.] )
P15
Total length of liquid Total length of liquid
pipe sized pipe sized
+
ø9.52 x 0.05 (kg/m) ø6.35 x 0.019 (kg/m)
45 (m) x 0.05 (kg/m) 40 (m) x 0.019 (kg/m)
2.25
+
6.01
6.1 kg (round-up)
Total length of liquid Total length of liquid
pipe sized pipe sized
+
ø ø
3/8" 0.55 [oz/ft.] 1/4"
x
147 (ft.) x 0.55 [oz/ft.] 129 (ft.) x 0.21 [oz/ft.]
80.85
+
213.94
214 [oz] (round-up)
3 units
6.7 kg 236 oz
Total capacity of
ø
9.52 connected indoor units
+
– 27 kBtu/h
28 – 54 kBtu/h
x 0.55 [oz/ft.]
55 – kBtu/h
A=ø9.52 [3/8"] 30 m [98 ft.] a=ø9.52 [3/8"] 15 m [49 ft.]
ø9.52 [3/8"] A + a = 30 + 15 = 45 m [148 ft.]
ø6.35 [1/4"] b + c + d = 10 + 10 + 20 = 40 m [131 ft.]
b ( 20 m [66 ft.] )
c ( 10 m [33 ft.] )
P08
Total capacity of
connected indoor units
+
– 27 kBtu/h
28 – 54 kBtu/h
55 – kBtu/h
0.76 3.00
+
Total capacity of
connected indoor units
+
0.21 [oz/ft.]
x – 27 kBtu/h
28 – 54 kBtu/h
55 – kBtu/h
27.09 106
+
SMART MULTI
Pipe size
Liquid pipe ø9.52
1.5 kg (53 oz)
2.5 kg (88 oz)
3.0 kg (106 oz)
b=ø6.35 [1/4"] 10 m [33 ft.]
c=ø6.35 [1/4"] 10 m [33 ft.]
d=ø6.35 [1/4"] 20 m [66 ft.]
P08
Pipe size
Liquid pipe ø9.52
1.5 kg (53 oz)
2.5 kg (88 oz)
3.0 kg (106 oz)
Pipe size
Liquid pipe ø9.52
1.5 kg (53 oz)
2.5 kg (88 oz)
3.0 kg (106 oz)
76