Checking Air Tightness of Pipes in Air/Liquid Heat Exchangers

Procedure

1. Check whether the pressure of the nitrogen that is pre-filled in the air/liquid heat exchanger for pressure preservation is normal. (If the residual pressure is greater than or equal to 50% of the pre-filling pressure, the nitrogen pressure is normal. Otherwise, the nitrogen pressure is abnormal.)
   • If yes, go to Checking Air Tightness of Manifold Pipes.
   • If no, perform the following steps to preserve the pressure of the air/liquid heat exchanger.

2. Connect any needle valve of the air/liquid exchanger to the pressure gauge.
   Figure 3-40 Connecting any needle valve of the air/liquid exchanger to the pressure gauge
   

3. Connect the air compressor and its transfer pipe to any needle valve, and increase the pressure by 600 kPa.
4. Disconnect the air compressor, keep it still for 5 minutes, and read and record the pressure gauge value P1. After maintaining the pressure for 1 hour, read and record the pressure gauge value P2.
5. Check whether the pressure drop ΔP exceeds 5 kPa (ΔP = P1 – P2).
   • If yes, contact Huawei technical support.
   • If no, go to 6.

6. Exhaust air from the pipe of the air/liquid heat exchanger.
   1. Connect the manual exhaust pipe to a needle valve.
      Figure 3-41 Connecting the manual exhaust pipe and a needle valve
      
   2. When air no longer comes out of the other side of the manual exhaust pipe, disconnect the manual exhaust pipe from the needle valve.

7. Connect the ball valve at the end of the air/liquid heat exchanger pipe to the primary side pipe. The red label indicates the water outlet pipe, and the blue label indicates the water inlet pipe.
   Figure 3-42 Connecting the quick connector of the air/liquid heat exchanger to the primary side pipe