Leak Test And Vacuum Drying - LG ZRUM080LTS6 Installation Manual

32

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 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
pressurization.
Heat Pump
Close
Close
Nitrogen Gas
Cylinder
Heat Recovery
Close
Close
Close
Nitrogen Gas
Cylinder
Nitrogen Gas
Cylinder
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
correction factor
There is a pressure change of approximately 0.01 MPa(1.5 psi) for
each 33.8 °F (1 °C) of temperature difference.
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(551
psi) is 80.6 °F (27 °C) 24 hour later:
3.73 MPa(541psi), 68 °F (20 °C) In this case the
pressure drop of 0.07 MPa (10 psi) is because of
temperature drop And hence there is no leakage in pipe
occurred.
CAUTION
!
To prevent the nitrogen from entering the refrigeration system in
the liquid state, the top of the cylinder must be at higher position
than the bottom when you pressurize the system.
Usually the cylinder is used in a vertical standing position.
When inserting nitrogen gas
of high pressure, it must be
used with regulator.
Close
Liquid Pipe
Indoor
Unit
Gas Pipe
When inserting nitrogen gas of
high pressure, it must be used
with regulator.
Liquid Pipe
HR unit
Gas Pipe
Vacuum
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, 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 -100.7 kPa (-
14.6 psi, 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 -100.7 kPa(-14.6 psi). 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(7.3 psi) (vacuum break) with nitrogen gas and then evacuate it
again with the vacuum pump for 1hr to -100.7 kPa(-14.6 psi)(vacuum
drying). If the system cannot be evacuated to -100.7 kPa(-14.6 psi)
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.
Heat Pump
Close
Scale
Use a gravimeter. (One that
can measure down to 0.1
kg (0.22 lbs)). If you are
unable to prepare such a
high-precision gravimeter
you may use a charge
cylinder.
Indoor Heat Recovery
Unit
Vacuum
pump
Close
Vacuum
pump
Scale
Use a gravimeter. (One that can measure
down to 0.1 kg (0.22 lbs)). If you are
unable to prepare such a high-precision
gravimeter you may use a charge cylinder.
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
!
Always add an appropriate amount of refrigerant. (For the
refrigerant additional charge)
Too much or too little refrigerant will cause trouble.
To use the Vacuum Mode (If the Vacuum mode is set, all valves
of Indoor units and Outdoor units will be opened.)
WARNING
!
When installing and moving the air conditioner to another site,
recharge after perfect evacuation.
- If a different refrigerant or air is mixed with the original
refrigerant, the refrigerant cycle may malfunction and the unit
may be damaged.
Close
Close
Close
Close
HR unit
Liquid side
Indoor unit
Gas side
Liquid side
Indoor unit
Gas side