Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document.
Note: Even the most advanced machine translation cannot match the quality of professional translators.
Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Vacuumizing
Prerequisites
- Before vacuumizing the cooling system, ensure that the refrigerant pipes have passed the air tightness test and do not leak.
- Before vacuumizing the cooling system, ensure that all connectors are secured.
- System high pressure may occur if the cooling system is not vacuumized or is not thoroughly vacuumized. Ensure that the cooling system is thoroughly vacuumized before refrigerant is charged.
Procedure
- Check whether a low-temperature component is installed
on the outdoor side.
- If no low-temperature component is installed on the outdoor side, connect the pressure gauge and vacuum pump at the low-pressure and exhaust pipe needle valves to vacuumzie the system simultaneously, as shown in Figure 4-1.
- If a low-temperature component is installed on the outdoor side, connect the pressure gauge and vacuum pump at the low-pressure, discharge pipe, and liquid pipe needle valves to vacuumzie the system simultaneously, as shown in Figure 4-2.
- In the beginning, the vacuum pump makes loud noise and exhausts white smoke from the exhaust vent. After 10 minutes, if it still exhausts white smoke, observe it for another 10 minutes because the cooling system may not be sealed properly or there may be too much refrigerant or water residues in the cooling system.
- After 20 minutes, the pressure gauge pointer should be in the negative area and the vacuum pump makes small noise. Close and open the pressure gauge alternatively for several times. The position of the pressure gauge pointer and the sound made by the vacuum pump do not obviously change. Otherwise, the cooling system may not be sealed properly.
- Vacuumize the cooling system for at least 80 minutes after checking that the cooling system does not leak. The pressure displayed on the vacuum pump should be less than or equal to 60 Pa (absolute pressure). When the pressure stops dropping, pump for another 10 minutes. The indication of sight glass is dry (green).
- Close all the pressure gauge valves, and the vacuum pump
after vacuumizing the cooling system. Preserve the pressure for 10
minutes without disconnecting the connection. The pressure should
be lower than and equal to 90 Pa (absolute pressure).
If the precision of the pressure gauge is too low to display 60 Pa (absolute pressure), ensure that the pressure gauge pointer stays at the minimum scale while vacuumizing the cooling system. Preserve the pressure for 1 hour, and make sure the displayed pressure does not increase obviously.
