Additional Refrigerant Charge; Calculation Of Additional Refrigerant Charge - Mitsubishi Electric City Multi PUHY-P72TKMU-A Installation Manual

<C> Slope of twinning pipes
Make sure the slope of the twinning pipes are at an angle within ±15˚ to the ground.
If the slope exceeds the specified angle, the unit may be damaged.
F
G
<D> Pipe connection example
H
A Downward slope B Upward slope
F Twinning pipe G Slope of the twinning pipes are at an angle within ±15˚ to the ground
I Twinning Kit J Straight run of pipe that is 500 mm [19-11/16 in] or more

10. Additional refrigerant charge

At the time of shipping, the outdoor unit is charged with refrigerant.
This charge does not include the amount needed for extended piping and
additional charging of each refrigerant line will be required on site. In order that
future servicing may be properly provided, always keep a record of the size and
length of each refrigerant line and the amount of additional charge by writing it in
the space provided on the outdoor unit.
10.1. Calculation of additional refrigerant
charge
• Calculate the amount of additional charge based on the length of the piping
extension and the size of the refrigerant line.
• Use the table below as a guide for calculating the amount of additional
charging and then charge the system accordingly.
• If the calculation results in a fraction of less than 0.1 kg [4 oz], round up
to the next 0.1 kg [4 oz]. For example, if the result of the calculation was
12.38 kg [437 oz], round the result up to 12.4 kg [438 oz].
<Calculating the amount of refrigerant to be charged>
Additional Total length of Total length of
refrigerant charge liquid pipe sized liquid pipe sized
ø19.05 mm [3/4 in] ø15.88 mm [5/8 in]
+
=
(kg) [oz] (m) × 0.29 (kg/m) (m) × 0.2 (kg/m)
(ft) × 3.12 (oz/ft) (ft) × 2.16 (oz/ft)
Total length of Total length of
liquid pipe sized liquid pipe sized
ø9.52 mm [3/8 in] ø6.35 mm [1/4 in]
+
+
(m) × 0.06 (kg/m) (m) × 0.024 (kg/m)
(ft) × 0.65 (oz/ft) (ft) × 0.26 (oz/ft)
Additional charge
Outdoor unit model Charged amount
+
P96
P120
P144
<Example>
Indoor
1: 48 A : ø12.7 mm [1/2 in] 40 m [131 ft] a : ø9.52 mm [3/8 in] 10 m [32 ft]
2: 36 B : ø9.52 mm [3/8 in] 10 m [32 ft] b : ø9.52 mm [3/8 in] 5 m [16 ft]
3: 15 C : ø9.52 mm [3/8 in] 15 m [49 ft] c : ø6.35 mm [1/4 in] 10 m [32 ft]
4: 12 D : ø9.52 mm [3/8 in] 10 m [32 ft] d : ø6.35 mm [1/4 in] 10 m [32 ft]
5: 24 e : ø9.52 mm [3/8 in] 10 m [32 ft]
I
H
J
C Indoor unit D Trap (gas pipe only)
The total length of each liquid line is as follows:
ø12.7 mm [1/2 in]: A = 40 m [131 ft] = 40 m [131 ft]
ø9.52 mm [3/8 in]: B + C + D + a + b + e
ø6.35 mm [1/4 in]: c + d = 10 m [32 ft] + 10 m [32 ft] = 20 m [64 ft]
Therefore,
<Calculation example>
Additional refrigerant charge
Value of α
Total length of
liquid pipe sized
ø12.7 mm [1/2 in]
+
(m) × 0.12 (kg/m)
(ft) × 1.30 (oz/ft)
<Amount of factory charged refrigerant>
+ α
2 kg
8 kg
At the
conditions
below:
E Within 2 m [6 ft]
H Pipes on site
= 10 m [32 ft] + 15 m [49 ft] + 10 m [32 ft] + 10 m [32 ft] +
5 m [16 ft] + 10 m [32 ft] = 60 m [193 ft]
= 40 m [131 ft] × 0.12 kg/m [1.30 oz/ft] + 60 m [193 ft] × 0.06 kg/m [0.65 oz/ft]
+ 20 m [64 ft] × 0.024 kg/m [0.26 oz/ft] + 3.5 kg [124 oz] = 12.4 kg [438 oz]
Total capacity of connecting indoor units
Models ~ 27
Models 28 ~ 54
Models 55 ~ 126
Models 127 ~ 144
Models 145 ~ 180
Models 181 ~ 234
Models 235 ~ 273
Models 274 ~ 307
Models 308 ~ 342
Models 343 ~ 411
Models 412 ~ 480
Models 481 ~
Outdoor unit model Charged amount
P72 9.0 kg
P96 11.5 kg
P120 11.8 kg
P144 11.8 kg
α
2.0 kg [71 oz]
2.5 kg [89 oz]
3.0 kg [106 oz]
3.5 kg [124 oz]
4.5 kg [159 oz]
5.0 kg [177 oz]
6.0 kg [212 oz]
8.0 kg [283 oz]
9.0 kg [318 oz]
10.0 kg [353 oz]
12.0 kg [424 oz]
14.0 kg [494 oz]
13