Refrigerant Piping System; Additional Refrigerant Charge; Calculation Of Additional Refrigerant Charge - Mitsubishi Electric City Multi PUHY-HP200YHM-A Installationshandbuch

Warning:
When installing and moving the unit, do not charge the system with any
other refrigerant other than the refrigerant specified on the unit.
- Mixing of a different refrigerant, air, etc. may cause the refrigerant cycle to mal-
function and may result in severe damage.
Caution:
• Use a vacuum pump with a reverse flow check valve.
- If the vacuum pump does not have a reverse flow check valve, the vacuum
pump oil may flow back into the refrigerant cycle and cause deterioration of
the refrigerator oil.
• Do not use the tools shown below used with conventional refrigerant.
(Gauge manifold, charge hose, gas leak detector, check valve, refrigerant
charge base, vacuum gauge, refrigerant recovery equipment)
- Mixing of conventional refrigerant and refrigerator oil may cause the refrig-
erator oil to deteriorate.
- Mixing of water will cause the refrigerator oil to deteriorate.
- R410A refrigerant does not contain any chlorine. Therefore, gas leak detec-
tors for conventional refrigerants will not react to it.
• Manage the tools used for R410A more carefully than normal.
- If dust, dirt, or water gets in the refrigerant cycle, the refrigerator oil will dete-
riorate.
• Never use existing refrigerant piping.
- The large amount of chlorine in conventional refrigerant and refrigerator oil
in the existing piping will cause the new refrigerant to deteriorate.
• Store the piping to be used during installation indoors and keep both
ends of the piping sealed until just before brazing.
- If dust, dirt, or water gets into the refrigerant cycle, the oil will deteriorate and
the compressor may fail.
• Do not use a charging cylinder.
- Using a charging cylinder may cause the refrigerant to deteriorate.
• Do not use special detergents for washing piping.

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 addi-
tional 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 to the right as a guide to calculating the amount of additional
charging and charge the system accordingly.
• If the calculation results in a fraction of less than 0.1 kg, round up to the next
0.1 kg. For example, if the result of the calculation was 11.38 kg, round the
result up to 11.4 kg.
<Additional Charge>
Additional Liquid pipe size
refrigerant charge Total length of
=
ø19.05 × 0.29
(kg) (m) × 0.29 (kg/m)
Liquid pipe size
Total length of
+
ø9.52 × 0.06
(m) × 0.06 (kg/m)
Liquid pipe size Liquid pipe size
Total length of Total length of
+ +
ø15.88 × 0.2 ø12.7 × 0.12
(m) × 0.2 (kg/m) (m) × 0.12 (kg/m)
Liquid pipe size
Total length of
+ + α
ø6.35 × 0.024
(m) × 0.024 (kg/m)

9.2. Refrigerant piping system

Connection example
[Fig. 9.2.1] (P.3, 4)
A Outdoor unit
C Indoor unit
E Outdoor twinning kit
*1 The pipe sizes listed in columns A1 to A3 in this table correspond to the sizes for
the models listed in the unit 1, 2, and 3 columns. When the order of the models for
unit 1, 2, and 3 change, make sure to use the appropriate pipe size.
Precautions for outdoor unit combinations
Refer to [Fig. 9.2.2] for the positioning of twinning pipes.
[Fig. 9.2.2] (P.5)
<A> Make sure the pipes from the twinning pipe to the outdoor unit are sloped down-
wards (towards the twinning pipes).
<B> When the piping on the outdoor unit side (from the twinning pipe) exceeds 2 m,
ensure a trap (gas pipe only) within 2 m. Make sure the height of the trap is 200
mm or more.
If there is no trap, oil can accumulate inside the pipe, causing a shortage of oil
and may damage the compressor.
<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.
<D> Pipe connection example
A Downward slope
C Indoor unit
E Within 2 m
G Slope of the twinning pipes are at an angle within ±15° to the ground
H Pipes on site
J Straight run of pipe that is 500 mm or more
<Example>
Indoor 1: 125 A: ø12.7 40 m
2: 100 B: ø9.52 10 m
3: 40 C: ø9.52 15 m
4: 32 D: ø9.52 10 m
5: 63
The total length of each liquid line is as follows:
ø12.7: A = 40 = 40 m
ø9.52: B + C + D + a + b + e = 10 + 15 + 10 + 10 + 5 + 10 = 60 m
ø6.35: c + d = 10 + 10 = 20 m
Therefore,
<Calculation example>
Additional refrigerant charge
= 40 × 0.12 + 60 × 0.06 + 20 × 0.024 + 3.5 = 12.4 kg
Value of α
Total capacity of connecting indoor units
Models ~ 80
Models 81 ~ 160
Models 161 ~ 330
Models 331 ~ 390
Models 391 ~ 480
Models 481 ~ 630
Models 631 ~ 650
B Branch
D Cap
B Upward slope
D Trap (gas pipe only)
F Twinning pipe
I Twinning kit
a: ø9.52 10 m
At the
b: ø9.52 5 m
conditions
c: ø6.35 10 m
below:
d: ø6.35 10 m
e: ø9.52 10 m
α
2.0 kg
2.5 kg
3.0 kg
3.5 kg
4.5 kg
5.0 kg
6.0 kg
15