44
PIPE CONNECTIONS BETWEEN INDOOR AND OUTDOOR UNIT
ENGLISH
Leak test
Leak test should be made by pressurizing nitrogen gas to 3.8 MPa(38.7kgf/cm
2
). 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.
Indoor unit
Nitrogen gas
cylinder
Slave 1 outdoor unit
Master outdoor unit
Liquide pipe
Gas pipe
Liquide pipe
Gas pipe
Liquid side
Gas side
Close
Close
Close
Close
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 0.1 kg/cm
2
(0.01 MPa) for each 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) is 27 °C
24 hour later: 3.73 MPa, 20°C
In this case the pressure drop of 0.07 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.
!
WARNING
Use a vacuum pump or Inert(nitrogen) gas when doing leakage test or air purge. Do not com-
press air or Oxygen and do not use Flammable gases. Otherwise, it may cause fire or explo-
sion.
- There is the risk of death, injury, fire or explosion.
!
Leak Test and Vacuum drying
1,MFL67798026,영영 19. 3. 14. 영영 4:49 Page 44
