4. Initial Startup
6
Adjust the branch balance valve of Unit 2 for it to reach the rated flow rate. Another person will observe the flow rate change of Unit
1, dynamically adjust the balance valve of the return water end and compensate water to enable Unit 1 to reach the rated flow rate
(±5%). After adjustment, record the opening of the branch balance valve of Unit 2.
7
Adjust the branch balance valve of Unit 3 for it to reach the rated flow rate. Another person will observe the flow rate change of Unit
1, dynamically adjust the branch balance valve of Unit 1 and compensate water to enable Unit 1 to reach the rated flow rate (±5%).
After adjustment, record the opening of the branch balance valve of Unit 3.
8
6
7
Repeat steps
~
9
When all units are adjusted, record the opening of the balance valve of the return water end and the total flow rate (rated flow rate
±10%).
10
If the circuit is unable to reach the rated value of the total flow rate after adjustment, adjust the water flow of the chiller and water
pump.
4.7 PID Setting
Due to differing data center environmental conditions, the PID parameter values must be adjusted by qualified service personnel after
installation to achieve the best cooling efficiency.
Note: First read 5.2 Control Panel Operation to get familiar with basic operation.
Path: Main Menu g Setting g Controller
y y
Proportional constant (P)
Adjust between the measured temperature and the set value.
y y
Integration constant (I)
Add or subtract the integration coefficient by small incremental output.
y y
Differential constant (D)
Adjust the output to correct the time-dependent correction rate.
The PID default values of the three-way ball valve are:
y y
Adjustment procedures
The adjustment is made based on an open circuit method as follows:
1
Keep the fans running at high speed (at least 70%) and observe the flow rates at the high, medium, and low openings of the
three-way ball valve from the control panel.
2
Adjust the three-way ball valve to the opening at half of the rated flow rate, which varies according to the pipeline configuration
and pressure distribution at site. If the opening is too large (above 70%), reduce it to a medium opening (about 50%).
3
When the temperature and humidity of outlet air and return air are stable, record the readings of time-dependent outlet air
temperature and observe if the inlet and outlet water temperatures are stable.
4
Use the control panel to start the manual mode and increase the opening (above 75%). Due to the internal delay of the system,
the outlet air temperature will change over time.
to adjust Units 4~6 and record the opening of the branch balance valves.
Force Mode
P Gain
I Gain
D Gain
(Figure 4-7: PID Setting Values)
P
9.00
:
OFF
:
09.00
:
0.550
:
0.000
I
D
0.55
0.000
24