Mitsubishi Electric City Multi PQHY-P72 Service Handbook page 172

(2) Example
Heat source unit
(Main pipe)
(3) Sample calculation
Heat source unit: 96 model
Indoor unit 1: 72 model
When
The aggregate length of each liquid pipe type.
19.05 [3/4"] : A = 40 m [130 ft]
9.52 [3/8"] : B + C + a + b + d = 35 m [112 ft]
6.35 [1/4"] : c + e = 20 m[65 ft]
According to the above formula
Amount of refrigerant to be charged (kg) = (0.16 X 40) + (0.06 X 35) + (0.024 X 20) + 2 + 1 = 11.98kg
The calculation result would be 11.98kg, and it is rounded up to the nearest 0.1kg.
The final result will be as follows:
Amount of refrigerant to be charged = 12.0kg
Amount of refrigerant to be charged (oz) = (1.72 X 130) + (0.65 X 112) + (0.26 X 65) + 71 + 36 = 420.3oz
The calculation result would be 420.3oz, and it is rounded up to the nearest 1 oz or 4 oz(0.1kg).
The final result will be as follows:
Amount of refrigerant to be charged = 424oz or 421oz
110 m [360 ft] or less
A
Main BC controller
a B
Indoor 1
(Model above P55
and below P96)
Maximum of 3 units per port
Total capacity of P54 or below
(All units connected to the same port
must be in the same operating mode.)
A: 19.05 [3/4"] 40 m [131 ft]
B: 9.52 [3/8"]
2: 24 model C: 9.52 [3/8"]
3: 18 model
4: 24 model
5: 06 model
- 163 -
To downstream units
A
Note : "Total sum of downstream unit model numbers"
in the table is the sum of the model numbers of
the units after point A in the figure.
Sub BC controller
C
40 m [131 ft] or less
Branch joint (For use with the Y series)
CMY-Y-102S-G
b c d
Indoor Indoor
3
2
Indoor
a: 9.52 [3/8"] 10 m [32 ft]
b: 9.52 [3/8"]
5 m [16 ft]
c: 6.35 [1/4"] 10 m [32 ft]
5 m [16 ft]
d: 9.52 [3/8"] 10 m [32 ft]
e: 6.35 [1/4"] 10 m [32 ft]
[ VIII Test Run Mode ]
e
Indoor
5
4
5 m [16 ft]