Refrigerant is indispensable in the operation of industrial chillers, serving as a fundamental condition for their normal functioning. To improve the cooling efficiency of the chiller, reduce consumption, and ensure safe operation, refrigerant is essential. Sometimes, industrial chillers may fail to cool down. While many would assume this is a problem, it could simply be that the chiller is "thirsty" and needs refrigerant. How then can you diagnose and handle refrigerant malfunctions in industrial chillers?
Symptoms of refrigerant deficiency in industrial chillers: poor cooling effect of the entire equipment, only slightly cool water outlet, and low pressure on both the high-pressure and low-pressure sides when checked with manifold pressure gauges (when the compressor is running at normal speed and the ambient temperature is around 35℃, the low-pressure gauge reading is below 1 kg/cm2 and the high-pressure gauge reading is below 10 kg/cm2). At the same time, bubbles can be seen flowing in the sight glass.
Fault cause analysis: There is a refrigerant leak in the refrigeration system of the industrial chiller, resulting in insufficient refrigerant.
Troubleshooting: Use an electronic leak detector to locate the leak and repair or replace the affected part. If the part has not been replaced, simply add an appropriate amount of refrigerant. If the part has been replaced, add the appropriate amount of refrigeration oil as required, and vacuum the chiller system before adding sufficient refrigerant.
Symptoms of overcharged refrigerant in industrial chillers: poor cooling effect; when checking with a manifold pressure gauge, both the high-pressure and low-pressure sides are found to be too high (when the compressor speed is normal and the ambient temperature is 35℃, the high-pressure gauge pressure is about 19 kg/cm2 and the low-pressure gauge pressure is 2.3 kg/cm2, and no bubbles are visible in the sight glass).
Fault Cause Analysis: Too much refrigerant was added to the chiller's refrigeration system, preventing it from fully utilizing its cooling capacity and resulting in poor cooling performance.
Troubleshooting: Connect a manifold pressure gauge to the system and slowly loosen the manual valve on the low-pressure side of the manifold pressure gauge to allow the refrigerant to drain slowly (do not drain from the high-pressure side, as draining refrigerant from the high-pressure side will bring out a large amount of refrigeration oil) until the high and low pressures are normal, and at the same time, you can see the refrigerant flowing clearly in the sight glass, with occasional bubbles flowing by.
Symptoms of air contamination in the refrigeration system of an industrial chiller: decreased overall cooling capacity; when checking with a manifold pressure gauge, the high-pressure side pressure is found to be too high, and the low-pressure side pressure is sometimes also higher than normal (when the compressor speed is normal and the ambient temperature is 35°C, the high-pressure side pressure is higher than 20 kg/cm2; and the high-pressure gauge pointer swings; on the other hand, many bubbles can be seen flowing through the sight glass).
Fault Cause Analysis: Air has entered the system. This is mainly due to incomplete vacuuming after assembly or overhaul; air being introduced into the system during refrigerant charging or adding refrigeration oil; or air entering through leaks when the system is operating under negative pressure. When air enters the refrigerant, it gains pressure, and since the refrigerant also has pressure, the total gas pressure in a closed container equals the sum of its component pressures. Therefore, both the high and low pressure gauge readings are higher than normal.
Troubleshooting steps: Release the refrigerant (slowly release it from the low-pressure side using a pressure gauge). Check the cleanliness of the compressor oil. Vacuum the system and then recharge with refrigerant.
