Causes and solutions of low pressure alarm of water chillers

Date:Oct 17, 2020

1. Leakage of cooling system 

     There are leakage points in the connecting pipe of cooling system, such as welding point leakage, corrosion leakage, cracking caused by mechanical vibration and human factors, all of which will lead to low-voltage fault. 

      Solution: First, use leak detector (soapy water or detergent mixed with water) or halogen leak detector to determine the leak point. After finding the leakage point, repair it with welding equipment, then keep the pressure to test the leakage point and vacuumize, and then fill the refrigerant according to the manufacturer's instructions, and the water chiller can resume normal operation. 

2. The cooling system is blocked 

(1). blocked by impurities If the filter is blocked by dust, it will only lead to a slight decrease in cooling capacity, and may not even be affected. When the filter is slightly blocked, there will be a temperature difference between the inlet and outlet of the filter, which can be felt by grasping the inlet and outlet by hand. In case of severe blockage, the filter will be dewed or frosted. If there is condensation or frost (except condensation after the cooler stops running under normal operation), it can be judged whether the filter is blocked. 

    Solution: Replace the filter of the same model.

(2). frozen The water in the system flows to the throttle valve (expansion valve) together with the refrigerant. After throttling expansion, it freezes at the outlet of throttle valve, thus blocking throttle valve (expansion valve) and causing low pressure fault. 

      Solution: Replace the filter of the same model. 

(3). expansion valve damaged The expansion valve will be affected by the environment in use. In some environments, corrosive gases can corrode liquids, thus corroding expansion valves. 

      Solution: replace the new expansion valve of the same model.

3. The heat exchange of evaporator is seriously insufficient. 

(1). insufficient water flow in evaporator The pump is broken or something bad enters the impeller of the pump, causing leakage in the inlet pipe of the pump (it is difficult to check and needs careful analysis), resulting in insufficient water flow. Solution: Replace the water pump. Or disassemble the water pump to remove the bad things in the impeller. 

(2). the evaporator is blocked by something bad First of all, the problem of water pump must be eliminated. When the equipment is normal, there will be no large amount of condensed water and frosting on the compressor surface. When you see a lot of condensed water and frost on the compressor surface, you can basically judge that the evaporator is blocked. Solution: If the evaporator is blocked or the evaporator tube is fouled, please remove the evaporator and the evaporator tube, and then rinse with a high-pressure water gun or soak and clean with special chemical liquid.

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