Liquid cooled high and low temperature testing chillers are widely used in various high and low temperature environment testing, especially in reliability testing of energy storage batteries, electronic products, automotive components and other industries, playing a crucial role. However, in practical use, the liquid cooled high and low temperature testing chiller may encounter ultra-high temperature alarm problems, mainly manifested as high pressure alarm and high water temperature alarm.

These alarms not only affect the normal operation of the equipment, but may also have adverse effects on the test results. Therefore, it is particularly important to understand the causes of ultra-high temperature alarms and take effective solutions. This article will analyze in detail the reasons for the ultra-high temperature alarm of the liquid cooled high and low temperature testing chiller, and provide corresponding solutions.

1 Types of alarms

• High voltage alarm

High pressure alarm is usually related to the heat dissipation problem of the condenser of the chiller. When the heat dissipation effect of the condenser is poor, the internal pressure of the system will be too high, causing the equipment to issue a high pressure alarm. The heat dissipation problem is usually closely related to external environmental temperature, poor ventilation, and cooling water flow rate.

• High water temperature alarm

The high water temperature alarm refers to the situation where the water temperature in the water tank of the liquid cooled high and low temperature test chiller exceeds the set threshold and continues to rise during operation. High water temperature is usually caused by the cooling system’s inability to take away heat in a timely manner, or a malfunction in the system itself, resulting in ineffective control of the water temperature.

2 Analysis of Common Causes of Ultra high Temperature Alarm

(1) Air cooled high pressure alarm

In air-cooled chillers, the condenser needs to rely on external air for heat dissipation. If the ventilation of the condenser is poor or the external air temperature is too high, it may cause the high pressure alarm of the chiller. Common reasons include:

Dust proof mesh blockage: The dust proof mesh is the first line of defense for the condenser of the chiller. If not cleaned for a long time, dust and dirt will accumulate on the dust proof mesh, affecting air circulation and leading to poor heat dissipation.

High cooling water temperature: If the temperature of the cooling water is too high, the heat dissipation effect will be significantly reduced, resulting in a high pressure alarm for the equipment.

Excessive refrigerant: Excessive refrigerant can cause high condenser pressure, resulting in a high pressure alarm.

(2) Water cooled high pressure alarm

For water-cooled chillers, heat dissipation is mainly achieved through water towers and water cooling systems. If the temperature of the cooling water is too high or the water flow is insufficient, it may also trigger a high pressure alarm. Common issues include:

• Water cooling tower malfunction: The malfunction of the water tower fan or the high cooling water temperature can affect the heat dissipation effect of the water cooling system, leading to a high pressure alarm.

Insufficient water and cold water flow: If the water flow in the water cooling system is insufficient, it cannot effectively remove heat and may also cause a high pressure alarm.

(3) Water temperature over high temperature alarm

The alarm for excessively high water temperature usually occurs in the water tank of the chiller. When the water temperature continues to rise and exceeds the preset range, the system will automatically sound an alarm. Common reasons include:

Voltage issue: Unstable or severely low voltage can affect the cooling effect of the chiller, resulting in excessively high water temperature.

Improper setting of temperature controller parameters: If the setting parameters of the temperature controller are not reasonable, it may cause the water temperature to be too high and trigger an alarm.

Frequent on-off of chiller: Frequent on-off can affect the cooling time of the equipment, resulting in ineffective reduction of water temperature.

Excessive heat load: When the heat load carried by the equipment exceeds the processing capacity of the chiller, the water temperature will quickly rise and exceed the set value.

3 Solution for ultra-high temperature alarm

To address the above issues, we can take the following measures to solve the problem of ultra-high temperature alarm in liquid cooled high and low temperature testing chillers:

(1) Solution to air-cooled high pressure alarm

Clean the dust screen: Regularly inspect and clean the dust screen on the condenser to ensure smooth air circulation. You can use an air gun or brush to clean the dust and dirt on the dust net.

Check the cooling water temperature and flow rate: For water-cooled chillers, check if the temperature and flow rate of the cooling water are normal. It can be ensured that the water cooling system can effectively dissipate heat by cleaning the cooling tower or adjusting the water flow rate.

• Control refrigerant dosage: If there is too much refrigerant, the refrigerant dosage in the system can be adjusted by releasing pressure. Ensure that the system pressure is within a reasonable range.

(2) Solution to Water Temperature Overheat Alarm

• Improve voltage stability: When the voltage is too low or unstable, it may affect the cooling effect. Improving the power supply line or installing a voltage regulator can ensure the voltage stability of the equipment.

Reset the parameters of the thermostat: Check the setting parameters of the thermostat to ensure that they meet the actual working requirements. If the parameter settings are incorrect, they can be reset or restored to factory settings.

• Ensure sufficient cooling time: Avoid frequent on/off and ensure that the chiller has enough time for cooling, usually requiring a running time of at least five minutes.
• Reduce heat load: When the heat load is too high, the cooling capacity of the chiller cannot meet the demand. At this point, you can choose to reduce the load or select a chiller with a larger cooling capacity as needed.

(3) Regular maintenance and inspection

Regular maintenance and inspection are crucial to ensure efficient operation of the chiller while avoiding the occurrence of ultra-high temperature alarms. Regularly inspect key components such as the condenser, evaporator, temperature controller, compressor, and water cooling system of the chiller, clean dirt and replace aging parts in a timely manner, and ensure the normal operation of the system.