Leak Test And Vacuum Drying - LG MULTI V Series Installation Manual

Header
Models Gas pipe
360
120
I.D 12.7
4 branch I.D 12.7
I.D 15.88
I.D 15.88
ARBL054
I.D 19.05
540
7 branch
I.D 12.7
I.D 15.88
I.D 15.88
ARBL057
I.D 19.05
400
160
I.D 15.88
I.D 12.7
4 branch
I.D 19.05
I.D 15.88
ARBL104
I.D 28.58 I.D 25.4
580
160
7 branch I.D 12.7
I.D 19.05
I.D 15.88
ARBL107
I.D 28.58 I.D 25.4
760
160
I.D 12.7
10 branch
I.D 19.05
I.D 15.88
ARBL1010
I.D 28.58 I.D 25.4
775
182
I.D 12.7
10 branch
I.D 15.88
I.D 19.05
ARBL2010
I.D 31.8 I.D 34.9
For more information, refer accessory installation manual.

Leak Test and Vacuum drying

Leak test
Leak test should be made by pressurizing nitrogen gas to 3.8 MPa(38.7
2
kgf/cm ). If the pressure does not drop for 24 hours, the system
passes the test. If the pressure drops, check where the nitrogen leaks.
For the test method, refer to the following figure. (Make a test with
the service valves closed. Be also sure to pressurize liquid pipe, gas
pipe and high/low pressure common pipe)
The test result can be judged good if the pressure has not be reduced
after leaving for about one day after completion of nitrogen gas
pressurization.
Slave 1 outdoor unit
Close
Nitrogen gas
Close
cylinder
[unit:mm]
Liquid pipe
360
120
I.D 6.35
I.D 6.35
I.D 9.52
120 150
120 150
I.D 9.52
I.D 15.88 I.D 12.7
I.D 9.52
540
120 120
I.D 12.7
150
I.D 9.52
120
I.D 15.88
I.D 12.7
360
120
I.D 6.35
I.D 6.35
120 150
I.D 9.52
I.D 9.52
I.D 22.2
I.D 12.7
700
120
I.D 15.88
I.D 6.35
120 150
I.D 9.52
I.D 9.52
I.D 22.2
I.D 12.7
720
120
I.D 15.88
I.D 6.35
120 150
I.D 9.52
I.D 9.52
I.D 12.7 I.D 9.52
I.D 22.2
700
60*9=540
I.D 15.88
I.D 6.35
120 150
I.D 9.52
I.D 15.88
I.D 9.52
I.D 28.58
Master outdoor unit
Close
Close
Liquid side
Gas side
WARNING
!
Use a vacuum pump or Inert(nitrogen) gas when doing leakage test
or air purge. Do not compress air or Oxygen and do not use
Flammable gases. Otherwise, it may cause fire or explosion.
- There is the risk of death, injury, fire or explosion.
NOTE
If the ambient temperature differs between the time when pressure is
applied and when the pressure drop is checked, apply the following
I.D 6.35
correction factor.
150
120 There is a pressure change of approximately 0.1 kg/cm
each 1 °C of temperature difference.
I.D 9.52
Correction= (Temp. at the time of pressurization – Temp. at the time
of check) X 0.1
For example: Temperature at the time of pressurization
(3.8 MPa) is 27 °C
120 150
24 hour later: 3.73 MPa, 20 °C
In this case the pressure drop of 0.07 is because of
I.D 9.52
temperature drop And hence there is no leakage in pipe
occurred.
I.D 6.35
120 150
CAUTION
!
I.D 9.52
To prevent the nitrogen from entering the refrigeration system in
the liquid state, the top of the cylinder must be at higher position
I.D 6.35
than the bottom when you pressurize the system.
120 150
Usually the cylinder is used in a vertical standing position.
107
I.D 6.35
Vacuum
120 150
Vacuum drying should be made from the service port provided on the outdoor
I.D 19.05
unit's service valve to the vacuum pump commonly used for liquid pipe, gas
pipe and high/low pressure common pipe. (Make Vacuum from liquid pipe, gas
pipe and high/low pressure common pipe with the service valve closed.)
* Never perform air purging using refrigerant.
• Vacuum drying: Use a vacuum pump that can evacuate to -100.7kPa
(5 Torr, -755 mmHg).
- Evacuate the system from the liquid and gas pipes with a vacuum
pump for over 2 hrs and bring the system to -100.7kPa. After
maintaining system under that condition for over 1 hr, confirm the
vacuum gauge rises. The system may contain moisture or leak.
- Following should be executed if there is a possibility of moisture
remaining inside the pipe.
(Rainwater may enter the pipe during work in the rainy season or
over a long period of time)
After evacuating the system for 2 hrs, give pressure to the system
to 0.05 MPa(vacuum break) with nitrogen gas and then evacuate it
again with the vacuum pump for 1hr to -100.7 kPa(vacuum drying).
If the system cannot be evacuated to -100.7 kPa within 2 hrs,
repeat the steps of vacuum break and its drying. Finally, check if the
vacuum gauge does not rise or not, after maintaining the system in
vacuum for 1 hr.
Slave 1 outdoor unit
Vacuum
pump
Indoor unit
Scale
Use a graviometer. (One that
can measure down to 0.1 kg). If
you are unable to prepare such a
high-precision gravimeter you
may use a charge cylinder.
2
(0.01 MPa) for
Master outdoor unit
Close
Close
Close
Close
21
Liquid side
Indoor unit
Gas side