Checking the Nitrogen Pressure

Procedure

1. Open the door lock using a key, and open the cabinet rear door.
2. Unfasten the rotating baffle plates, and remove the air filters.
   Figure 4-27 Removing air filters
   

   If the baffle plates cannot be rotated manually, loosen the screws that secure the baffle plates using a Phillips screwdriver until they can be rotated open manually.

3. Take out the desiccant bag.
4. Check whether any of the needle valve bonnets shown in Figure 4-28 is missing by turns.
   1. If they do not exist, contact Huawei technical support.
   2. If they exist, remove each valve bonnet and use it to press the valve plugs in turn. If nitrogen is exhausted, the system is working properly. If no nitrogen is exhausted, contact Huawei technical support.
   Figure 4-28 Positions of the needle valves
   

   (1) Low-pressure needle valve

   (2) Discharge pipe needle valve

   (3) Liquid pipe needle valve