1. Six causes and solutions for low pressure alarms of chillers
Low pressure alarms of chillers are a common problem, but by understanding their possible causes and corresponding solutions, we can effectively deal with this problem. When a low pressure alarm occurs in a chiller, we first need to check the suction pressure of the compressor. Under normal circumstances, the suction pressure of the compressor should be maintained in the range of 0.4~0.6MPa. If the suction pressure is lower than 0.2MPa, the low pressure protection relay will start to act, resulting in a low pressure alarm. This situation is usually caused by insufficient return air volume, which in turn causes the cooling capacity to fail to meet the demand, and ultimately causes unnecessary waste of electricity. Therefore, we need to pay close attention to and deal with this problem.
Next, we will explore the six possible causes of low pressure alarms of chillers:
2. Verify whether the cooling water temperature is too low
During the operation of the chiller, if the outside temperature is low and the cooling water is started at a low temperature, or the refrigeration oil temperature is too low so that the refrigerant cannot be fully separated, a low pressure alarm will be triggered. For these two situations, we can take corresponding measures: if the cooling water temperature is too low, the water temperature can be increased by shutting down the cooling tower or adjusting the cooling water volume; if the refrigerant oil temperature is too low, the preheating time of the chiller needs to be extended. After the refrigerant oil temperature returns to the normal range, the low pressure problem can be solved.
3. Check whether the evaporator is blocked
The evaporator plays an important role in heat exchange in the chiller. If the evaporator is blocked, the refrigerant will not evaporate normally, which will affect the operation of the chiller. Therefore, during daily maintenance, we need to backwash the chiller regularly to ensure that the evaporator is unobstructed.
4. Pay attention to the state of the refrigerant
The refrigerant is an indispensable element in the chiller, and its adequacy is directly related to the operating efficiency of the unit. If the refrigerant is insufficient or leaking, it must be replenished or repaired in time to ensure the stable operation of the chiller.
5. Check the state of the low-voltage protection relay
The low-voltage protection relay plays a vital role in the chiller. However, it sometimes short-circuits due to moisture or is damaged due to poor contact, which can cause communication failures and lead to false alarms. Therefore, we need to check the status of the low-voltage protection relay regularly to ensure that it works properly.
6. Review the expansion valve status of the chiller
If the chiller has a low-pressure fault under the premise of ensuring sufficient refrigerant, one of the possible reasons is that the expansion valve is not open enough or is blocked. This usually occurs when the cooling unit is running for a long time in a low-temperature environment, or the unit is suddenly running after not starting for a long time. In general, the fault can be restored by itself by letting the unit run for a period of time.
6. Troubleshoot air and water shortage in the chiller system
If there is air or water shortage in the chiller system, it will cause insufficient refrigerant water flow, which will affect the effect of absorbing heat and refrigerant. In addition, supercooling and steam supersaturation may cause wet compression, which will reduce the pressure difference between the inlet and outlet water of the unit, increase the temperature difference, reduce the suction temperature, and frost on the suction port. To solve this problem, an exhaust valve can be installed at a high point in the pipeline for exhaust, and ensure that the pipeline filter is properly selected and has sufficient water permeability. At the same time, check whether the water pump flow matches the system. If adjustment is needed, choose a suitable water pump and clean the filter regularly.