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4. Installing the refrigerant piping
A
4.7. Additional refrigerant charge
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 ad-
ditional refrigerant at the installation site. In addition, in order to carry out service, en-
ter 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.
* When the unit is stopped, charge the unit with the additional refrigerant through the
liquid stop valve after the pipe extensions and indoor units have been vacuumized.
When the unit is operating, add refrigerant to the gas check valve using a safety
charger. Do not add liquid refrigerant directly to the check valve.
Calculation of additional refrigerant charge
• Calculate the additional charge using the liquid pipe size and length of the extended
piping and total capacity of connected indoor units.
• Calculate the additional refrigerant charge using the procedure shown to the right,
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 6.01 kg, round up the charge to 6.1 kg.)
• The amount of additional refrigerant which is calculated from the total capacity
of indoor units and the combination of extended pipes must not be over 16.3 kg
(575 oz).
(Refer to 2.5. for the capacity of indoor units, and 4.1. for extended piping.)
en
5. Drainage piping work
Outdoor unit drainage pipe connection
When drain piping is necessary, use the drain socket or the drain pan (option).
Drain socket
Drain pan
15
E
F
G
B
HI
LO
K
C
D
Fig. 4-13
* The figure to the left is an example only.
The stop valve shape, service port
position, etc., may vary according to the
model.
* Turn section A only.
(Do not further tighten sections A and
B together.)
C Charge hose
D Service port
Fig. 4-14
PAC-SK27DS-E
PAC-SJ83DP-E
4.6. Refrigerant pipe airtight testing method
Airtight test (Fig. 4-13)
Airtight test should be made by pressurizing nitrogen gas. For the test method, refer
to the following figure.
H
(1) Connecting the testing tool. Make a test with the stop valve closed. Be also sure
to pressurize both liquid or high-pressure pipe and gas or low pressure pipe.
I
(2) D o not add pressure to the specified pressure all at once; add pressure little by
little.
1 P ressurize to 0.5 MPa [73 psig], wait five minutes, and make sure the pressure
does not decrease.
2 P ressurize to 1.5 MPa [218 psig], wait five minutes, and make sure the pres-
sure does not decrease.
3 Pressurize to 4.15 MPa [601 psig] and measure the surrounding temperature
and refrigerant pressure.
(3) I f the specified pressure holds for about one day and does not decrease, the
pipes have passed the test and there are no leaks.
• If the surrounding temperature changes by 1°C [1.8°F], the pressure will change
by about 0.01 MPa [1.5 psig]. Make the necessary corrections.
(4) If the pressure decreases in steps (2) or (3), there is a gas leak. Look for the
source of the gas leak.
A Nitrogen gas
B System analyzer
C Lo-knob
D Hi-knob
E To indoor unit
Precautions when using the charge valve (Fig. 4-14)
Do not tighten the service port too much when installing it, otherwise, the valve core
could be deformed and become loose, causing a gas leak.
After positioning section B in the desired direction, turn section A only and tighten it.
Do not further tighten sections A and B together after tightening section A.
<Additional Charge>
Calculation of refrigerant charge
Pipe size
Pipe size
Liquid pipe
Liquid pipe
ø6.35
+
ø9.52
(m) × 19.0 (g/m)
(m) × 50.0 (g/m)
{(ft) × 0.21 (oz/ft)}
{(ft) × 0.55 (oz/ft)}
Included refrigerant amount when shipped from the factory
Model name
MXZ-SM72/96/120
<Example>
Outdoor model : MXZ-SM120TAM
Indoor 1 : model 27
2 : model 27
3 : model 27
4 : model 27
5 : model 12
The total length of each liquid line is as follows:
ø12.7 (1/2) : A = 30 m (98 ft)
ø9.52 (3/8) : a + b + c + d = 45 m (145 ft)
ø6.35 (1/4) : e = 15 m (49 ft)
The total capacity of connected indoor unit is as follows:
27 + 27 + 27 + 27 + 12 = 120
<Calculation example>
Additional refrigerant charge
92.0
+ 45 ×
30 ×
1000
(98 × 0.99 + 145 × 0.55 + 49 × 0.21 + 159 = 347 oz)
F Outdoor unit
G Stop valve
H Liquid pipe or high-pressure pipe
I Gas pipe or low-pressure pipe
K Service port
Pipe size
Total capacity
Liquid pipe
of connected
+
ø12.7
+
indoor units
(m) × 92.0 (g/m)
{(ft) × 0.99 (oz/ft)}
55 ― 92
93 ― 105
106 ― 116
117 ― 124
125 ― 133
134 ― 139
Included refrigerant amount
9.3 kg (328 oz)
A : ø12.7 30 m (98 ft)
a : ø9.52 15 m (49 ft)
b : ø9.52 10 m (32 ft)
c : ø9.52 10 m (32 ft)
d : ø9.52 10 m (32 ft)
e : ø6.35 15 m (49 ft)
50.0
19.0
+ 15 ×
+ 4.5 = 9.8 kg (rounded up)
1000
1000
Amount for the
indoor units
― 54
2.5 kg (88 oz)
3.0 kg (106 oz)
3.5 kg (123 oz)
4.0 kg (141 oz)
4.5 kg (159 oz)
5.0 kg (176 oz)
5.5 kg (194 oz)
140 ―
6.1 kg (215 oz)
At the conditions
below:
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