Cause Analysis and Treatment Method of Copper Tube Leakage of Evaporator of Single Cooling Unit

Cause Analysis and Treatment Method of Copper Tube Leakage of Evaporator of Single Cooling Unit A central air-conditioning system in a public area uses a screw chiller. During operation, a copper tube in the evaporator leaks due to a malfunction. After further inspection by the technical staff, it was confirmed that the fault was leakage of the copper pipe of the evaporator of the chiller. After the inspection tools and required materials were in place, the copper pipes were inspected for leaks, and several copper pipes were found to be leaky. In order to minimize the impact of equipment failures, immediately deal with the faulty chiller and formulate a maintenance plan. Cause Analysis After the on-site inspection and analysis of the fault, the preliminary judgment of the cause of the fault has the following aspects. The copper tubes in the evaporator of this unit may have quality problems. This chiller has been used for more than 6 years, and similar failures have occurred in other units of the same type. Although the broken copper pipe has not been tested, it cannot be completely determined that it is caused by the quality of the copper pipe, but this reason cannot be ruled out. The direct cause of the copper tube rupture after the leak analysis is that the overcooling in the copper tube causes the frozen water to freeze and cause the copper tube to rupture. During the on-site inspection, it was found that the water flow switch was not sensitive, and there was no action when the fault occurred. Analysis of the causes of this problem has the following aspects. The overheating protection of the chilled water pump stops the pump, causing the chilled water to stop circulating, and the water flow switch fails, there is no freezing point protection in the evaporator, and the chiller continues to run, causing the supercooling to freeze until the copper pipe ruptures and leaks; As a result, the chilled water in the copper pipe stopped circulating, and the water flow switch failed, and there was no freezing point protection in the evaporator, which caused supercooling and freezing until the copper pipe broke and leaked; but the valve was found to be normal in the post-examination, and there was no closing record in the record. This reason; the power switch of the chiller is running, the chilled water pump is out of sync with the chiller, the chilled water stops circulating, and the water flow switch fails, the evaporator has no freezing point protection, and the chiller continues to run, causing the supercooling to freeze until The copper pipe cracked and leaked. However, this reason was excluded when checking the records afterwards. After analysis, due to the discharge of the latter two factors, this situation is more likely to cause the copper pipe to break. Non-air conditioning season maintenance is not in place. The non-air conditioning season has just ended. During the non-air conditioning season maintenance, maintenance work such as replacing freezing oil, replacing filter cores, and replenishing refrigerants were carried out. In the air-conditioning season, the equipment malfunctions within a short period of time, and the impact of non-air-conditioning season maintenance on the normal operation of the equipment cannot be ruled out. The maintenance personnel* skills are not high enough to find hidden dangers before the equipment fails. After shutting down and shutting down that night, the maintenance personnel were not sufficiently vigilant about equipment failures. When they found that the evaporation pressure was too low, they did not attract enough attention and took no remedial measures, resulting in extensive damage to the copper pipes. At the same time, failure to properly handle equipment failures after power outages resulted in early shift personnel failing to understand the failures in time when they were turned on and missing the best time to rescue equipment in time