Thermostatic Expansion Valve Operation, Adjustment

Component Operation and Maintenance

6.4.4Thermostatic Expansion Valve Operation

The thermostatic expansion valve performs one function. It keeps the evaporator supplied with enough refrigerant to satisfy load conditions. It does not effect compressor operation.

Proper valve operation can be determined by measuring superheat. If too little refrigerant is being fed to the evaporator, the superheat will be high; if too much refrigerant is being supplied, the superheat will be low. The correct superheat setting is between 10 and 15°F (5.6 and 8.3°C).

Adjustment

To adjust the superheat setting, proceed as follows:

1.Remove the valve cap at the bottom of the valve.

2.Turn the adjusting stem counterclockwise to lower the superheat.

3.Turn the adjusting stem clockwise to increase the superheat.

NOTE

Make no more than one turn of the stem at a time. As long as 30 minutes may be required for the new balance to take place.

6.4.5Hot Gas Bypass Valve Operation

The hot gas bypass is inserted between the compressor discharge line and the leaving side of the expansion valve through the side outlet distributor. The system, with normal operation when the evaporator is under full load, will maintain enough pressure on the leaving side of the hot gas valve to keep the valve port closed.

If the load on the evaporator decreases, the evaporator will get colder. When the coil is too cold, the internal pressure in the evaporator drops and allows the hot gas bypass valve to open. Hot gas then mixes with the liquid coolant on the discharge side of the expansion valve raising the temperature and pressure in the evaporator. The net result is a reduction in the cooling capacity of the unit to match the load.

To aid in lubricating the compressor, the hot gas bypass solenoid is delayed for 30 seconds on the ini- tial call for cooling and de-energized for 30 seconds during every 60 minutes of continuous operation.

Adjustment

Upon deciding what evaporator temperature is desired, the following procedure should be used to adjust the hot gas bypass valve:

1.Install the suction and discharge pressure gauge.

2.Adjust the temperature setpoint to call for cooling so that the refrigeration compressor will run.

3.Remove the TOP adjusting nut from the valve.

4.Insert an Allen wrench in the brass hole at top of the valve in adjusting port, and turn CLOCKWISE if a higher evaporator temperature is required.

5.After obtaining the suction pressure required, reinstall the cap tightly making sure there are no leaks.

6.Let the evaporator operate for approximately 10 to 15 minutes to make sure the suction pressure is within the desired range.

7.There will be a fluctuation of approximately 3 to 6 PSIG (21 to 41 kPa) on the evaporator due to the differential on the hot gas bypass.

8.Return the temperature setpoint to desired number.

3000 specifications

The Liebert 3000 is a cutting-edge power protection solution designed to provide reliable and efficient backup power for critical applications. This uninterruptible power supply (UPS) system is engineered to safeguard sensitive electronic equipment from power disturbances, ensuring uninterrupted operations in data centers, telecommunications, and industrial environments.

One of the standout features of the Liebert 3000 is its high-efficiency design. With an efficiency rating of up to 94%, the system minimizes energy loss, resulting in lower operational costs and a reduced carbon footprint. This is particularly important in today's environmentally conscious climate, as organizations strive to meet sustainability goals while maintaining top-tier performance.

The Liebert 3000 employs advanced technologies to enhance its functionality. It incorporates online double-conversion technology, which provides a continuous supply of clean and regulated power. This technology ensures that connected loads receive stable voltage and frequency, shielding them from voltage spikes, sags, and outages. Additionally, the UPS offers features such as automatic battery testing, which helps ensure peak battery performance and reliability.

Another key characteristic of the Liebert 3000 is its modular design, allowing for flexible scalability. This means that organizations can easily expand the capacity of their UPS system as their power needs grow, without the need for extensive system overhauls. The modular architecture also facilitates simplified maintenance and reduces downtime, as individual modules can be serviced without interrupting power to the critical load.

The system is equipped with comprehensive monitoring and management capabilities. The Liebert 3000 provides real-time data on power usage, battery status, and system performance, enabling facility managers to make informed decisions and proactively address potential issues. The integration of remote management tools allows for seamless monitoring from anywhere, providing peace of mind for operators.

Overall, the Liebert 3000 combines high efficiency, advanced technology, and flexible design to deliver a robust power protection solution. Its reliability and performance make it a preferred choice for organizations seeking to protect their critical infrastructure while enhancing operational efficiency and sustainability. As businesses continue to rely on technology for their everyday operations, the Liebert 3000 stands out as a dependable safeguard against the uncertainties of power quality.