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Chapter 1: Introduction
1.5.4 Condensate Pump
A condensate pump is factory installed in the lower drain pan. The pump automatically eliminates condensate water from the
drain pan. The pump has an internal float switch that turns the pump on and off based on the water level.
1.5.5 EC Fans
The unit is equipped with three high-efficiency, Electronically Commutated (EC) fans. EC fans use a brushless motor equipped
with permanent magnets and permanently lubricated ball bearings. The fan impellers are curved backward and attached to the
rotor casing. The fan is balanced and aerodynamically optimized to minimize vibration.
The fans do not use drive belts. Fan speed is variable via a 0- to 10-VDC signal from the system controller. The fan motor is
equipped with integral electronics and does not require the addition of secondary electronics such as thermal protection,
inverters, or filters. The fan will not produce AC inverter whine.
During startup, the fans begin operating in stages with five-second time delays. The middle fan starts first, then the upper fan,
then the lower fan. The system controller monitors fan operation. If one or two of the fans fails to operate, the controller alerts
the operator with an alarm message and increases the speed of the remaining fan(s) to compensate for the loss of airflow.
Use the system controller to configure the fans for zone temperature control with independently variable fan speeds or with all
three fans operating at the same variable speed (See Section 4.4.4).
1.5.6 Temperature/Humidity Sensors
Controls and alarms are recognized controller by analyzing signal inputs from the sensors to manage the operation of the A/C
unit consistent with the setpoints entered in the system controller. The system controller monitors three NTC-type temperature
sensors and a 4–20 mA temperature/humidity (T/H) sensor.
The NTC sensors are factory-installed in predetermined supply air fan zones inside the cabinet. Each NTC sensor is used by the
system controller to manage the speed of the fan for that zone to meet the supply air setpoint temperature. The return air is
monitored by a temperature/humidity (T/H) sensor that is typically mounted inside the cabinet. As an option, you can remove the
return air T/H sensor from the cabinet and mount it in the hot aisle. View the actual sensor values from the controller user
interface display using the Information menu loop.
1.6 Optional Equipment
1.6.1 Remote Mounted Supply Temperature/Humidity Sensor
As an option, a supply T/H sensor may be provided for field installation (see Section 2.6.2). This is to be mounted in the supply
(cold aisle) space for monitoring or control purposes. Refer to the electrical drawing supplied with your unit for wiring details
specific to your system.
1.6.2 Humidifier
CRCW-24 systems may be equipped with an optional electrode steam humidifier. The humidifier is factory-installed inside the air
conditioner and includes fill and drain valves and associated piping to the top (or bottom) of the cabinet for connecting a source
of water and a drain line.
Operation of the humidifier's fill and drain cycles is based on water conductivity and is maintained by the humidifier controller.
An operating manual for the humidifier is provided under separate cover. Refer to that manual for detailed information on the
operation of the humidifier.
1.6.3 Water Detector
As an option, Black Box offers spot-type or strip-/cable-type water detectors (see Section 2.6.1). Upon sensing a leak, the water
detector control circuit will signal the system controller of the alarm condition. The system controller is programmed to shut down
the compressor and the fans when a leak is detected.
1.6.4 Smoke Detector
Optionally mounted in the return air side of the cabinet, a photo-electric smoke detector senses the presence of smoke and
signals the controller when a smoke alarm condition exists and shuts down the air conditioner.
724-746-5500 | blackbox.com
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Table of Contents
Troubleshooting
