
18 Installation & Commissioning Guide ECOFLEX MINI VRF R-32 SERIES - OUTDOOR
Doc. No.9590-5028-01 Ver. 2 230913
Installation Manual ECOFLEX MINI VRF R-32 SERIES
05.06. Airtight Test
Air tightness test – OFN (Oxygen Free Nitrogen) must be used.
Increase the pressure from the liquid pipe and gas pipe to 4.0 MPa at the same time (not exceeding 4.0 MPa). If the pressure
does not drop in 24 hours, the test is passed.
When the pressure drops, check the leakage position. After you make sure that there is no leakage, discharge the nitrogen.
CAUTION
• Never use oxygen, combustible gas, or poisonous gas in the air tightness test.
• To prevent damage to the equipment, the pressure must not be held for too long.
05.07. Air Purge with Vacuum Pump
• Use a vacuum pump that can evacuate the pipe to a pressure of less than -100.7 kPa (5000 Micron Hg, -754997 Micron
Hg). When the pump is stopped, do not let the pump oil flow back into the refrigerant pipe.
• The liquid and gas pipes should be evacuated with a vacuum pump for more than two hours to a pressure of less than
-100.7kPa.
• Then, place the pipes at pressure of less than -100.7 kPa for more than one hour, and check whether the reading of the
vacuum gauge rises.
(If the reading rises, there is residual water or gas leakage in the system. The leakage must be checked and solved and
the test should be performed again.)
• Water may enter into pipes under the following circumstances: the installation is carried out in a rainy season and the
installation period is long; the pipes are condensed inside; rainwater enters the pipes.
• After the above vacuum drying of two hours, use nitrogen to increase the pressure to 0.05 MPa (vacuum breaking),
and use a vacuum pump to decrease the pressure to lower than -100.7kPa or below and hold the pressure for one hour
(vacuum drying).
• If the pressure cannot be decreased to lower than -100.7 kPa after two-hour vacuumizing, repeat the vacuum breaking
and vacuum process. After that, place the vacuum pipes for one hour, and then check whether the reading of the
vacuum gauge rises.
WARNING
• During the maintenance process, it is necessary to enter the vacuum mode when purging air.
• If the system is configured with a refrigerant shut-off device, vacuuming needs to be done from the maintenance needle
valves of the Outdoor Unit check valves and the refrigerant shut-off device separately. In additional, only vacuuming from
the Outdoor Unit is also allowed when the system is powered on and the Outdoor Unit is without any error code of Ad1, C21,
C26, C28, C2A and EC1.
05.08. Refrigerant Amount to be Added
WARNING
• Use only R-32 as the refrigerant. Other substances may cause explosions and accidents.
• R-32 contains fluorinated greenhouse gases, and the GWP value is 675. Do not discharge the gas into the surroundings.
• When charging the refrigerant, make sure you wear protective gloves and safety glasses. Be careful when you open the
refrigerant piping.
• Charge the refrigerant only after the system has not failed the gas tightness tests and vacuum drying.
• Ensure that the refrigeration system is earthed prior to charging the system with refrigerant.
• Add the refrigerant amount according to the calculation results. Extreme care shall be taken not to overfill the refrigeration
system.
• The system shall be leak tested on completion of charging but prior to commissioning. A follow up leak test shall be carried
out prior to leaving the site.
• If the system is configured with a refrigerant shut-off device, charging may need to be done separately from the
maintenance needle valves of the Outdoor Unit check valves and the refrigerant shut-off device. In additional, only charging
from the Outdoor Unit is also allowed when the system is powered on and the Outdoor Unit is without any error code of
Ad1, C21, C26, C28, C2A and EC1.