Chilled Water Control; Figure 18 Dip Switch Locations On Liebert Icom Control Board - Emerson Liebert Challenger 3000 User Manual

3.2.3

Chilled Water Control

The chilled water control valve is adjusted proportionally as the temperature control varies the
requirement for cooling from 0% to 100%. A three-point actuator or motorized ball valve is used for
chilled water cooling, as well as free-cooling hot water or heating.
The three-point actuator is driven through two digital outputs: Open and Close. The control deter-
mines the valve position by timing how long the open or closed signals have been active based on the
valve travel time set in the Service menu / Setup submenu. To determine the initial position of the
valve, the unit must perform a 3P Reset. The 3P Reset closes the valve for a time of 110% of the 3P
Actuator run time. This calibrates the valve with the controller and ensures that it is closed. A 3P
Reset is also performed if the fan is switched off for any reason (timer off, unit off, etc.). Once the reset
is performed.
The three-point actuator can be configured to utilize the pre-wired feedback signal provided from the
factory. Enabling the feedback signal will eliminate the need to drive the valve closed after a loss of
power or Unit Off command, decreasing the unit's restart time. Authorized Emerson personnel should
use the following steps to enable the feedback signal:
1. The feedback on the control valve uses Analog Input 1.
2. Nothing can be connected to Analog Input 1 P11 pins 1 through 4.
3. Control board DIP switch SW2 Switch 1 must be ON, Switch 2 must be OFF.

Figure 18 DIP switch locations on Liebert iCOM control board

4. P68 must have a jumper placed between the top and bottom two pins on the left side and one
placed between the top and bottom pins on the right side, the two middle pins should be left
unconnected.
5. Next go to Service/Diagnostics Service Menu and find S379. Set this option to Feedback and note
that S380 will go to Yes and S381 will go to Ongoing. If Feedback is already selected then go to
line S380 and manually select Yes. This means that the Liebert iCOM is doing auto calibration on
the valve using the feedback now available through the potentiometer. Wait for S381 to say Idle
and then the process is complete.
22
Operation