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Page 31
Chapter 2: Installation
2.9 Chilled Water System Preparation
No field refrigerant charging is required for CW units. The following precautions must be observed when installing and filling the
CW loop:
• The piping system must be cleaned prior to allowing chilled water to flow through the system.
• When filling the chilled water loop, all air must be bled from the piping system.
1. Open a vent valve at the highest point of the system.
2. Fill the system until the solution is discharging from the vent with minimal signs of foaming due to air in the system.
3. Fill out applicable blocks of the Warranty Registration and Start-Up Checklist.
2.10 Settings and Adjustments
2.10.1 Chilled Water Circuit
In a chilled water A/C unit, cooling is maintained by the flow of chilled water through a cooling coil. A water valve proportionally
opens to increase the flow as the temperature rises (or closes as the temperature falls). If the unit is turned off, the valve will
return to the closed position, shutting off flow through the coil. Chilled Water control valves are available in 2-way or 3-way
configurations. Refer to the piping drawing supplied with your unit to determine which type valve is provided.
Location and size of chilled water valve differs with the size of the A/C unit. The chilled water valves are factory set for the correct
operating position and should not require field adjustment.
2.10.2 EC Fans
The speed of the EC fans is controlled via a 0– to 10–VDC signal from the system controller. The controller is preset by the
factory for the correct fan speed configuration and should not require adjustment. If the airflow needs to be adjusted, this may be
done using the controller’s programming menu selections. Refer to Section 4.4.4 for instructions on adjusting airflow using the
system controller. Contact Black Box Technical Support at 724-746-5500 or info@blackbox.com when initially making adjustments
to the controller.
2.10.3 Humidifier Adjustment
The humidifier has an adjustable capacity potentiometer on the humidifier control circuit board. The potentiometer may need to
be field adjusted if the humidifier is not supplying enough capacity for the current room conditions.
If you need to adjust the humidifier capacity, do it in small increments and verify them. Refer to the humidifier manual sent with
your unit for the capacity potentiometer location.
CAUTION
Adjusting the capacity potentiometer too high may cause condensate to form within the system.