Leak Test And Vacuum Drying - LG Multi V IV PRHR041 Installation Manual

Header
Models Gas pipe
360
120
ID12.7
ID12.7
4 branch
ID15.88
ARBL054 ID15.88
ID19.05
ID15.88
ID19.05
540
7 branch
ID12.7
ARBL057
ID15.88
ID15.88
ID19.05
400
160
ID15.88
ID12.7
4 branch
ID19.05
ID15.88
ARBL104
ID28.58 ID25.4
580
7 branch
ID12.7
ID19.05
ARBL107
ID15.88
ID28.58 ID25.4
760
160
10 branch ID12.7
ID19.05
ID15.88
ARBL1010
ID28.58 ID25.4
775
10 branch ID12.7
ID19.05
ID15.88
ARBL2010
ID31.8 ID34.9

Leak Test and Vacuum drying

Leak test
Leak test should be made by pressurizing nitrogen gas to 3.8
2
MPa(38.7kgf/cm ). If the pressure does not drop for 24 hours, the sys-
tem 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 pressure gas 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 pres-
surization.
Slave 1 outdoor unit
Nitrogen gas
Close
cylinder Close
Close
Nitrogen gas
cylinder
[unit:mm]
Liquid pipe
360
120
ID6.35
ID6.35
ID9.52
150
120 ID9.52
ID15.88
ID12.7 ID9.52
ID12.7 ID9.52
540
120
120
ID12.7
150 ID9.52
120
ID15.88
ID12.7
360
120
ID6.35
ID6.35
ID9.52
150
120
ID9.52
ID22.2
ID12.7
700
160 120
ID15.88
ID6.35
150 ID9.52
ID9.52
120
ID12.7
ID22.2
760
160
ID15.88
ID12.7
150
ID19.05
120
ID15.88
ID22.2 ID28.58 ID25.4
700
182
60*9=540 107
ID15.88
ID6.35
150
120 ID9.52
ID15.88
ID9.52
ID28.58
Master outdoor unit
Close
Close
Close
Liquid side
HR unit
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 Flamma-
ble gases. Otherwise, it may cause fire or explosion.
- There is the risk of death, injury, fire or explosion.
150
120
NOTE
!
If the ambient temperature differs between the time when pressure is
applied and when the pressure drop is checked, apply the following
correction factor
ID6.35 There is a pressure change of approximately 0.1 kg/cm
each 1°C of temperature difference.
120 150
Correction= (Temp. at the time of pressurization – Temp. at the time
of check) X 0.1
ID9.52
For example: Temperature at the time of pressurization
(3.8 MPa) is 27 °C
24 hour later: 3.73 MPa, 20°C
In this case the pressure drop of 0.07 is because of tem-
150
120
perature drop And hence there is no leakage in pipe oc-
curred.
ID9.52
CAUTION
!
ID6.35
150 To prevent the nitrogen from entering the refrigeration system in
120
the liquid state, the top of the cylinder must be at higher position
than the bottom when you pressurize the system.
ID9.52
Usually the cylinder is used in a vertical standing position.
ID15.88
150
120
Vacuum
ID22.2
Vacuum drying should be made from the service port provided on the outdoor
unit's service valve to the vacuum pump commonly used for Liquid pipe, Low
Pressure Gas pipes, High Pressure Gas pipe. (Make Vacuum from Liquid pipe,
Low Pressure Gas pipes, High Pressure Gas pipe with the service valve
ID6.35
closed.)
150
120
* Never perform air purging using refrigerant.
ID19.05
• Vacuum drying: Use a vacuum pump that can evacuate to -100.7kPa
(5 Torr, -755mmHg).
- 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 main-
taining 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 re-
maining 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
0.05MPa(vacuum break) with nitrogen gas and then evacuate it again
with the vacuum pump for 1hr to -100.7kPa(vacuum drying). If the
system cannot be evacuated to -100.7kPa 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
Close
Vacuum
pump
Indoor unit
Scale
Use a graviometer. (One that can measure
down to 0.1kg). If you are unable to
prepare such a high-precision gravimeter
you may use a charge cylinder.
2
Master outdoor unit
Close
Close
Close
Close
Close
21
(0.01 MPa) for
Liquid side
Indoor unit
HR unit
Gas side