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Six Reasons and Solutions for Low Pressure Alarm of Chiller

Sep. 10, 2020

What to do with the low-pressure alarm of the chiller? First, the low-pressure failure of the water chiller is due to the compressor suction pressure being too low. The compressor's normal suction pressure is 0.4~0.6MPa. When the suction pressure is lower than 0.2MPa, the low-pressure protection relay will act. If it is too low, the return air volume is lacking, and the cooling capacity cannot meet the requirements, which will cause unnecessary power loss. Therefore, the water-cooled chiller factory is here to talk about the six possible reasons for the low-pressure alarm:

1. Check whether the temperature of the cooling water is too low. When the outside temperature is too low, the cooling water is turned on and running at low temperatures; or the temperature of the refrigerating oil is too low, and the refrigerator cannot be completely separated, which will cause low-pressure failure. If the temperature of the cooling water is too low, shut down the cooling tower or throttle the cooling water to cool the water temperature. If the temperature of the refrigerating oil is too low, the preheating time of the chiller can be extended, and the refrigerating oil temperature can be solved by returning to normal.

2. Check whether the evaporator is blocked. The blockage of the evaporator causes poor heat exchange and the refrigerant cannot evaporate. Therefore, the chiller should be backwashed regularly during routine maintenance.

Water Cooled Screw Chiller

3. Check if the refrigerant is insufficient or leaking.

4. Check whether the low-voltage protection relay is damaged. The low-voltage protection relay is short-circuited, poorly contacted, or damaged due to damp, causing communication failures and false alarms.

5. Check the expansion valve of the chiller. If the refrigerant is enough, the expansion valve is too small or blocked, which will also cause the low-pressure failure of the screw chiller. This problem is mostly caused by the low-temperature operation of the cooling unit or when the cooling unit has not been operated for a long period of time, and the chiller only needs to run for a period of time to return to normal.

6. Check whether there is air or lack of water in the chiller system. When there is air or lack of water in the chiller system, it will cause insufficient refrigerant water flow, poor heat absorption effect, poor refrigerant effect, and supercooling and steam oversaturation. It will produce wet compression, causing the unit to reduce the pressure difference between the inlet and outlet water, the temperature difference becomes larger, the suction temperature is low, and the suction port is frosted. The solution is to install an exhaust valve at the height of the pipeline to exhaust; the pipeline filter is blocked or the selection is too fine, and the water permeability is limited. The filter should be selected and the filter should be cleaned regularly. The flow rate of the water pump is small and does not match the system. The low-pressure failure of the flow chiller should be selected because the suction pressure of the compressor is too low. The normal suction pressure of the compressor is 0.4~0.6MPa. When the suction pressure is lower than 0.2MPa, the low-pressure protection relay will act. If the air pressure is too low, the return air volume is lacking, and the cooling capacity cannot meet the requirements, the unnecessary power loss will occur.


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