Additional Refrigerant Charge; Calculation Of Additional Refrigerant Charge - Mitsubishi Electric CITY MULTI PUHY-P-ZKMU-A Installation Manual

<C> Slope of twinning pipes
G
<D> Pipe connection example
H
A Downward slope B Upward slope
F Twinning pipe G
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>
When the piping length from the outdoor unit to the farthest indoor unit is
30.5 m [100 ft] or shorter.
Additional Total length of
refrigerant charge liquid pipe sized
ø19.05 mm [3/4 in]
=
(kg) [oz] (m) × 0.29 (kg/m)
(ft) × 3.12 (oz/ft)
Total length of
liquid pipe sized
ø9.52 mm [3/8 in]
+
(m) × 0.06 (kg/m)
(ft) × 0.65 (oz/ft)
Additional charge
Outdoor unit model
+ P96
P120
P144
* When connecting PLFY-P08NBMU-E2, add 0.3 kg of refrigerant per indoor
unit.
F
I
H
J
C Indoor unit
Total length of Total length of
liquid pipe sized liquid pipe sized
ø15.88 mm [5/8 in] ø12.7 mm [1/2 in]
+
+
(m) × 0.2 (kg/m) (m) × 0.12 (kg/m)
(ft) × 2.16 (oz/ft) (ft) × 1.30 (oz/ft)
Total length of
liquid pipe sized
ø6.35 mm [1/4 in]
+
(m) × 0.024 (kg/m)
(ft) × 0.26 (oz/ft)
Charged amount
2 kg +
8 kg
D Trap (gas pipe only)
When the piping length from the outdoor unit to the farthest indoor unit is
longer than 30.5 m [100 ft].
Additional Total length of
refrigerant charge liquid pipe sized
ø19.05 mm [3/4 in]
=
(kg) [oz] (m) × 0.26 (kg/m)
(ft) × 2.80 (oz/ft)
Total length of
liquid pipe sized
ø9.52 mm [3/8 in]
+
(m) × 0.054 (kg/m)
(ft) × 0.58 (oz/ft)
Additional charge
Outdoor unit model
+ P96
P120
P144
* When connecting PLFY-P08NBMU-E2, add 0.3 kg of refrigerant per indoor
unit.
<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
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
= 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]
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
= 40 m [131 ft] 0.12 kg/m [1.30 oz/ft] + 60 m [193 ft]
+ 20 m [64 ft] 0.024 kg/m [0.26 oz/ft] + 3.5 kg [124 oz] = 12.4 kg [438 oz]
E Within 2 m [6 ft]
H Pipes on site
Total length of Total length of
liquid pipe sized liquid pipe sized
ø15.88 mm [5/8 in] ø12.7 mm [1/2 in]
+
+
(m) × 0.18 (kg/m) (m) × 0.11 (kg/m)
(ft) × 1.94 (oz/ft) (ft) × 1.19 (oz/ft)
Total length of
liquid pipe sized
ø6.35 mm [1/4 in]
+
(m) × 0.021 (kg/m)
(ft) × 0.23 (oz/ft)
Charged amount
2 kg +
8 kg
At the
conditions
below:
e : ø9.52 mm [3/8 in] 10 m [32 ft]
0.06 kg/m [0.65 oz/ft]
13