Additional Refrigerant Charge; Drainage Piping Work - Mitsubishi Electric MXZ-8C48NA2 Manuel D'installation

4. Installing the refrigerant piping
A
A Nitrogen gas
B System analyzer
C Lo-knob
D Hi-knob
E To branch box

4.9. 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 addi-
tional refrigerant at the installation site. In addition, in order to carry out service, enter
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 vacu-
umized.
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 ex-
tended 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.)
en

5. Drainage piping work

Outdoor unit drainage pipe connection
When drain piping is necessary, use the drain socket or the drain pan (option).
However, it can not be used for MXZ-*C**NAHZ (Hyper Heating model)
Drain socket
Drain pan
11
E
B
HI
LO
C D
F Outdoor unit
G Stop valve
H Liquid pipe or high-pressure pipe
I Gas pipe or low-pressure pipe
K Service port
Fig. 4-11
* 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
A
D Service port
B
Fig. 4-12
C
D
PAC-SG61DS-E
PAC-SH97DP-E
4.7. Refrigerant pipe airtight testing method (Fig. 4-11)
F
(1) Connect the testing tools.
G
• Make sure the stop valves A B are closed and do not open them.
H
• Add pressure to the refrigerant lines through the service port C of the liquid
stop valve A and the gas stop valve B.
(2) Do not add pressure to the specified pressure all at once; add pressure little by
I
little.
1 Pressurize to 0.5 MPa [73 PSIG], wait five minutes, and make sure the pres-
sure does not decrease.
K
2 Pressurize to 1.5 MPa [218 PSIG], wait five minutes, and make sure the
pressure does not decrease.
3 Pressurize to 4.15 MPa [601 PSIG] and measure the surrounding tempera-
ture and refrigerant pressure.
(3) If 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.
4.8. Stop valve opening method
The stop valve opening method varies according to the outdoor unit model. Use the
appropriate method to open the stop valves.
(1) Gas side (Fig. 4-9)
1 Remove the cap, pull the handle toward you and rotate 1/4 turn in a counterclock-
wise direction to open.
2 Make sure that the stop valve is open completely, push in the handle and rotate
the cap back to its original position.
(2) Liquid side (Fig. 4-10)
1 Remove the cap and turn the valve rod counterclockwise as far as it will go with
the use of a 4 mm [3/16"] hexagonal wrench. Stop turning when it hits the stopper.
2 Make sure that the stop valve is open completely and rotate the cap back to its
original position.
Precautions when using the charge valve (Fig.4-12)
A
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.
Warning:
• When opening or closing the valve below freezing temperatures, refriger-
ant may spurt out from the gap between the valve stem and the valve body,
resulting in injuries.
• When installing the unit, securely connect the refrigerant pipes before
starting the compressor.
<Additional Charge>
Calculation of refrigerant charge
Pipe size
Liquid pipe
ø6.35
4C36/5C42/ (m) × 19.0 (g/m)
8C48 (0.21 (oz/ft))
(m) × 27.0 (g/m)
8C60
(0.29 (oz/ft))
Included refrigerant amount when shipped from the factory
Included refrigerant amount
4C36/5C42/
4.8 kg (169 oz)
8C48
8C60 5.1 kg (180 oz)
<Example>
Outdoor model : MXZ-8C60NA2
Indoor 1 : model 24
2 : model 15
3 : model 08
4 : model 08
The total length of each liquid line is as follows:
ø9.52 : A + a = 30 + 15 = 45 m (148 ft)
ø6.35 : b + c + d = 10 + 10 + 20 = 40 m (131 ft)
The total capacity of connected indoor unit is as follows:
24 + 15 + 08 + 08 = 55
<Calculation example>
Additional refrigerant charge
19.0
+ 45 ×
40 ×
1000
(131 × 0.21 + 148 × 0.55 + 106 = 215 oz)
Pipe size Total capacity
Liquid pipe of connected
ø9.52 indoor units
+ 4C36/5C42/ (m) × 50.0 (g/m) +
8C48 (0.55 (oz/ft))
(m) × 70.0 (g/m)
8C60
(0.75 (oz/ft))
A : ø9.52 30 m (98 ft)
a : ø9.52 15 m (49 ft)
b : ø6.35 10 m (33 ft)
c : ø6.35 10 m (33 ft)
d : ø6.35 20 m (66 ft)
50.0
+ 3.0 = 6.1 kg (rounded up)
1000
Amount for the
indoor units
– 27 1.5 kg (53 oz)
28 – 54 2.5 kg (88 oz)
55 – 3.0 kg (106 oz)
At the conditions
below: