Chapter 5: Maintenance

5.1.6 A/C System

Check the refrigerant sight glass on a monthly basis while the unit is running and ensure it is free of bubbles. Bubbles in the sight glass indicate a low refrigerant charge or a clogged filter-drier. Check for humidity in the refrigerant by viewing the color of the indicator in the center of the sight glass and comparing it to the color scale on the outer ring. If humidity is present, the system must be evacuated and recharged.

Check the superheat and sub-cooling temperatures semi-annually and ensure they are within the range shown in the refrigerant pressure/temperature table (Tables 2-9–2-11) in Section 2.10.3. If necessary, adjust the refrigerant charge to achieve the correct values. If the

refrigerant level is low, check the system for leaks.

5.2 Troubleshooting

Turn off all power to the unit before conducting any troubleshooting procedures, unless the procedure specifically requires the system to operate. For troubleshooting purposes, the system may be operated with the doors open by using a pair of channel lock pliers to turn the shaft of the main power disconnect switch to the “On” position. When the switch is turned on, high voltage will be present inside the cabinet. Exercise caution to prevent injury. Keep hands, clothing, and tools clear of the electrical terminals and rotating components. Ensure that your footing is stable at all times.

Symptom: Airflow too low.

Probable Cause: Dirty air filters (reduced airflow).

Recommendation: Clean/replace filters.

Symptom: EC fan(s) fail to start.

Probable Causes/Recommendations:

a. Power failure. Check main voltage power source input cable.

b. Motor starter protector tripped. Reset motor starter protector and check amperage of motor.

c. Control transformer circuit breaker tripped. Check for short circuit or ground fault; if none, reset circuit breaker.

d. Condensate overflow switch open.

1.Ensure unit is level.

2.Check that condensate pan is draining.

e.Defective contactor. Repair or replace.

f.No control signal to fan(s). Check the control I/O board for a 0-10 VDC control signal to the fan(s). Refer to the electric drawing to determine the correct I/O board terminal numbers. This must done within 15 seconds of turning the disconnect switch “On” or the controller will go into “Air Proving Alarm” mode.

g.EC fan’s internal overheat protection. Determine the cause of the interruption and correct. Possible causes are:

1.Blocked rotor.

2.Low supply voltage > 5 seconds.

3.Loss of phase > 5 seconds.

After causes 1, 2, and 3 are corrected, the motor will automatically reset.

After the causes below are corrected, the fan(s) must be manually reset by turning off power for 20 seconds:

4.Over temperature of electronics.

5.Over temperature of motor.

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Black Box CRDX-G-FS-12KW, CRDX-W-FS-12KW, CRDX-A-FS-24KW, CRDX-G-FS-24KW, CRDX-W-FS-24KW 6 A/C System, Troubleshooting
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CRDX-W-FS-12KW, Black Box Cold Row DX, CRDX-W-FS-24KW, CRDX-A-FS-24KW, CRDX-A-FS-12KW specifications

The Black Box CRDX series consists of high-performance cooling solutions designed to maintain optimal temperature conditions in data centers and server rooms. Key models in this series include the CRDX-W-FS-12KW, CRDX-W-FS-24KW, CRDX-G-FS-12KW, and CRDX-A-FS-24KW. These units are engineered to provide efficient cooling while addressing the rising demands of modern IT infrastructure.

One of the standout features of the CRDX series is its cold row design. This configuration enables targeted cooling delivery directly to the equipment, enhancing efficiency and reducing energy consumption. The airflow management in these models ensures that cooled air is directed where it is needed most, minimizing hotspots and maximizing cooling performance.

Both the CRDX-W-FS-12KW and CRDX-W-FS-24KW models utilize advanced refrigerant-based cooling technology. These units are equipped with electronically commutated (EC) fans, which are highly efficient and quieter than traditional fan technologies. This innovation not only lowers operational costs but also creates a more comfortable environment within the data center.

The CRDX-G-FS-12KW model stands out for its hybrid capabilities, offering both chilled water and direct expansion cooling options. This versatility allows facility managers to choose the best cooling approach based on their specific requirements and current infrastructure. The hybrid system can optimize energy consumption and enhance cooling efficiency, contributing to lower operating costs.

Another noteworthy feature across these models is their intelligent controls and monitoring capabilities. Equipped with sophisticated sensors and control systems, operators can gain real-time insights into temperature fluctuations, humidity levels, and unit performance. This data aids in proactive maintenance and ensures that cooling systems are operating at peak efficiency.

The CRDX-A-FS-24KW, on the other hand, is designed with a focus on adaptability and scalability. This model can be integrated easily into existing network setups, making it an excellent choice for facilities that anticipate future growth or need to adapt to changing cooling demands.

Overall, the Black Box CRDX series exemplifies the latest advancements in cooling technology, offering innovative features designed to support high-density computing environments. With their efficient cooling capabilities, intelligent controls, and flexible design options, these models provide reliable solutions for data centers looking to enhance their cooling systems while reducing operating costs.
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