Why Is a Chiller Overheating in Summer

Signs of chiller overheating

•Increased condensing pressure
•Increased outlet water temperature
•Frequent compressor shutdowns or alarms
•Fan running at full speed but no improvement
•Decreased cooling efficiency, unstable load

Causes and solutions for chiller overheating in summer

Decreased heat exchange efficiency of the condenser

The manifestation of decreased heat exchange efficiency of the condenser is high condensing temperature, high compressor pressure, and radiator surface temperature significantly higher than the environment. From the experience of LNEYA maintenance personnel, most of the cases are due to dirty and blocked condenser fins. Use compressed air or water gun to clean the condenser regularly to ensure that the condenser is unobstructed. Adding a protective net in a high dust environment and cleaning it regularly can effectively solve the problem.

Excessive ambient temperature

Excessive ambient temperature will cause the outlet and inlet temperatures of air-cooled chillers to be high. If the equipment is installed in a poorly ventilated area, hot air will circulate around the equipment, causing the exhausted hot air to be re-inhaled, forming a hot air short circuit. An infrared thermometer can be used to test whether the air temperature at the condenser inlet is more than 5°C higher than the ambient temperature, and preliminarily determine whether there is hot air reflux. If this happens, check whether the air outlet direction of the condenser is blocked, adjust the installation position of the equipment, add a top or wall exhaust fan, and install a hot air guide pipe and a hood if necessary to ensure good ventilation conditions.

Insufficient cooling water or air volume

When the cooling water flow or fan air volume is insufficient, the condenser temperature is difficult to drop, which will increase the compressor suction temperature and increase the compressor load. This can be caused by blockage of the cooling water pipe or damage to the fan. The operation of the fan and cooling water system should be checked regularly, and the dirt on the pipes, fan blades and condenser should be cleaned in time.

Low refrigerant level

Low refrigerant level will cause insufficient liquid inflow to the evaporator, resulting in a decrease in evaporation pressure and an increase in evaporation temperature. It may be caused by insufficient refrigerant filling, abnormal expansion valve opening or refrigerant leakage. The refrigerant level, system pressure and other parameters should be checked regularly, and the refrigerant should be replenished in time. If necessary, the expansion valve should be calibrated or replaced.

High load on the compressor

The high temperature of the compressor casing and the dull sound of operation indicate that it is running at high load. It is usually caused by aging of the lubricating oil or lack of unloading control and unreasonable start-stop strategy. Load distribution or frequency conversion control should be set up to pre-cool the compressor and implement staggered start-up. Check and replace lubricants regularly.

Unstable voltage

Summer is the peak season for electricity consumption. Severe voltage fluctuations will cause the cooling fan speed to be insufficient and sometimes fast and sometimes slow. You can install a voltage stabilizer or UPS to adjust the compressor start time to avoid the peak period from 12 noon to 4 pm. It is best to start before 7 am in the morning and set a 1-3 minute delay start logic.

Unreasonable temperature control settings

If the temperature hysteresis of the chiller is too small and the upper and lower limits are too narrow, it will trigger the start frequently. It will not only affect the cooling effect, but also aggravate mechanical fatigue and shorten the life of the equipment. The control system hysteresis value and start-stop logic should be adjusted, and the start delay time should be set for the multi-compressor system.

Improper selection

If your equipment is in full load operation for a long time and still cannot reach the set temperature, it means that its power cannot meet your application requirements. When selecting, you need to evaluate the cooling needs, consider seasonal extreme loads, and select chillers with a reserved capacity of 10-15%. If necessary, multiple devices can be operated in parallel to help share the load.

How LNEYA can help you?

Overheating of chillers in summer is generally caused by the superposition of multiple factors. If you are not sure which one caused the equipment abnormality, you can contact LNEYA, and we can provide you with remote diagnosis or on-site inspection services. LNEYA has industrial chillers with various performances for sale, which can be customized according to your application. If you want to start a new project or upgrade equipment, contact LNEYA for selection guidance and free quotes.