Air-Cooled Models

3.4.3Charging

1.Make sure unit is OFF. Open all disconnect switches and, on units supplied with circuit breakers, open all breakers. Replace all fuses for the Fan and Compressors or close breakers.

2.Remove jumper on the Fan Safety Switch and reconnect the system wire connections. Ensure that all operational components are clear of debris. Turn unit ON. (Fan operation is required.) Check the evaporator fan for proper rotation and correct if necessary.

3.Connect the refrigerant gauge charging hose to the drum of refrigerant and to the suction and discharge service valves of the compressor.

4.Calculate the amount of charge for the system. Weigh in as much of the system charge as possible. Refer to the unit, condenser and refrigerant line charge tables.

5.Set the control temperature setpoint (see operation manual) to 60°F (15°C) and set the % relative humidity setpoint higher than the conditioned room ambient to ensure that solenoid valves and hot gas bypass valves are open during the charging procedure. You may have to bypass the

LP Switch (low pressure switch) to start the compressors and stop short cycling. Reset the Head Pressure switch(es) if open.

6.Add refrigerant (R407C liquid, or R22 vapor per unit nameplate) to the suction side of the compressor until there is sufficient pressure to energize the low-pressure switch.

NOTE

When adding refrigerant to an operating system, it may be necessary to add the refrigerant through the compressor suction service valve. Because the refrigerant leaving the refrigerant cylinder must be in a liquid state, care must be exercised to avoid damage to the compressor. It is suggested that a sight glass be connected between the charging hose and the compressor suction service valve. This will permit adjustment of the cylinder hand valve so that liquid can leave the cylinder while allowing vapor to enter the compressor.

Then you may remove the manual bypass you applied earlier.

7.Charge the unit until the liquid line sight glass becomes clear. Then add one additional pound of refrigerant.

8.As head pressure builds, the condenser fan starts rotating. The fan becomes fully energized when sufficient head pressure is developed. (Fan starts to rotate at 190 psi and is full speed at 250 psi.)

Table 9

Refrigerant control settings psi (kPa)

 

 

 

Low Pressure

Low Pressure

High Pressure

Cut Out

Cut In

Cut Out

20 (137.9)

65 (448.2)

360 (2482)

 

 

 

 

3.5Lee-Temp/Flood Back Head Pressure Control Systems

The Lee-Temp system consists of a modulating type head pressure control valve and insulated receiver with heater pad to ensure operation at ambient temperatures as low as -30°F (-34.4°C).

3.5.1Piping

Lee-Temp systems have two factory-supplied, field-installed check valves: one on the discharge side of the scroll compressor and one on the inlet side of the receiver. Be sure to install the check valves with the refrigerant flow in the proper direction. When soldering or brazing the valves, it is very important that the internal parts be protected by wrapping the valve with a damp cloth to keep the valve tem- perature below 250°F (121°C).

20

Page 25 Page 27
Page 26
Image 26
Liebert ITR Lee-Temp/Flood Back Head Pressure Control Systems, Charging, Piping, Refrigerant control settings psi kPa
Page 25 Page 27

ITR specifications

The Liebert ITR is an advanced precision cooling unit designed to maintain optimal temperature and humidity levels in mission-critical environments. Engineered for high-performance applications, it is particularly suitable for data centers, telecommunications facilities, and other spaces that require precise climate control to ensure uninterrupted operation of sensitive equipment.

One of the main features of the Liebert ITR is its modular design. This allows for scalability and flexibility, enabling users to customize the system based on their specific cooling needs. The unit can be configured in various sizes and cooling capacities, making it suitable for both small server rooms and large data centers. This adaptability is crucial for organizations that anticipate growth and require an efficient cooling solution that can evolve with their infrastructure.

The Liebert ITR incorporates state-of-the-art technologies to enhance performance and energy efficiency. Among these technologies is the use of a variable speed compressor that adjusts its speed based on the cooling load. This capability not only improves energy efficiency but also significantly reduces operational costs by minimizing electricity consumption when cooling demands fluctuate.

Additionally, the unit features advanced control systems that provide intelligent monitoring and management of temperature and humidity levels. These systems can integrate seamlessly with building management systems (BMS) and can be operated remotely, providing users with real-time insights into the performance of the cooling system. Such connectivity ensures quick identification and resolution of potential issues, thereby reducing downtime and maintaining optimal conditions for critical equipment.

The Liebert ITR utilizes eco-friendly refrigerants, contributing to reduced environmental impact while ensuring compliance with regulatory standards. The unit's design also emphasizes reliability, featuring robust construction and redundant components that enhance longevity and minimize the likelihood of failures.

Furthermore, the Liebert ITR is equipped with advanced filtration systems that maintain air quality by reducing particulate matter and contaminants, ensuring that the atmosphere within data centers is not only cool but also clean—critical for the longevity of sensitive electronic equipment.

Overall, the Liebert ITR is characterized by its innovative design, energy-efficient operation, and comprehensive control capabilities, making it an ideal choice for businesses looking to safeguard their critical infrastructure from overheating and humidity. As climate control becomes increasingly important in the digital age, the Liebert ITR stands out as a reliable solution for maintaining optimal environmental conditions.
Top Page Image Contents