Hazards of Water Ingress in the Refrigeration System and Reference for Treatment Methods

1. Ice Blockage Phenomenon
   When moisture enters the refrigeration system and mixes with the refrigerant, as it passes through throttling devices such as the expansion valve or capillary tube, due to the decrease in temperature, the moisture may freeze into ice blocks, causing ice blockage. In this situation, the flow of the refrigerant is obstructed, resulting in poor liquid supply and affecting the normal operation of the entire system.
2. Lubricating Oil Emulsification
   After moisture comes into contact with the lubricating oil, it may cause the emulsification of the lubricating oil. This will greatly reduce the lubricating performance of the lubricating oil, thereby affecting the working efficiency and service life of the compressor and other moving parts.
3. Corrosion Effect
   Moisture in the refrigeration system can chemically react with the refrigerant to generate corrosive substances such as hydrochloric acid and hydrogen fluoride. These substances will cause serious corrosion to metal components, especially key parts such as valves, bearings and shaft seals, shortening the service life of the equipment and increasing the maintenance cost.
4. Impact on Electrical Insulation
   The presence of moisture may also reduce the electrical insulation performance of the refrigerant. For fully enclosed compressors, this can be fatal, as it may increase the risk of the motor burning out.
5. System Stability Issues
   Excessive moisture may also lead to abnormal internal pressure in the system. For example, the pressure on the high-pressure side may rise, which not only increases the working load of the compressor but may also trigger the operation of the high-pressure protection device, causing the unit to stop.

For Detecting Leakage Points

• Condenser: Add a small amount of refrigerant and then pressurize the system with nitrogen to 10 Kg. Check the possible leakage points with soapy water or a detergent - water solution.
• Evaporator: Observe whether there are oil stains in the chilled water. If there are, it indicates a leak; if not, there is no leak.
• Refrigerant with Water: Release an appropriate amount of refrigerant from the cylinder into a clean and dry glass container. After the refrigerant has evaporated, check if there is water in the container. If there is, it means the refrigerant in this cylinder has a high water content. Trace its source.

Treatment Methods for Systems with a Large Amount of Water Ingress

1. Disassemble Refrigeration System Components: Disassemble components such as the condenser, evaporator, compressor (remove the oil filter), high - pressure dry filter, expansion valve, solenoid valve, stop valve, liquid storage tank, and connecting pipes (large components do not necessarily need to be moved) to facilitate the next steps.
2. Sectional Blow - down: Use the method of pressurizing with nitrogen and then releasing it instantaneously to blow out as much water as possible from the components. If the refrigerant system pipeline is complex, according to the specific situation, use a welding torch to heat the pipeline at certain parts and then blow out the water section by section.
3. Reassemble the Refrigeration System: After reassembling the entire unit, open all passages in the refrigeration system (do not install the expansion valve spool, high - pressure dry filter element, and solenoid valve spool for now; do not add the oil filter and refrigeration oil in the compressor for now). Evacuate the system for a longer time than usual (it is best to heat the components; the compressor can be connected to the oil heater to help the remaining water in the system evaporate more quickly).
4. Start the Unit: After confirming that the water in the system has been basically removed, reassemble the refrigeration system, install a clean oil filter and high - pressure dry filter element, add refrigeration oil, and follow the normal assembly sequence of the unit.

Treatment Methods for Systems with a Small Amount of Water Ingress

1. Replace the Filter: First, replace the high - pressure dry filter of the unit system. If it is a dry filter barrel, you can make a bag with clean and dry degreased gauze and then fill it with “activated alumina particles” and a certain amount of color - changing silica gel (to facilitate observing the water content). Replace the refrigeration oil containing water in the compressor.
2. Replace the Filter Again: After the unit has been running for some time, replace the dry filter again. Pay attention to observing the color - changing silica gel to judge the water content in the system. Repeat this operation sequence.
3. Start the Unit: After confirming that the water in the system has been basically removed, replace the clean oil filter, high - pressure dry filter element, and refrigeration oil, and follow the normal assembly sequence of the unit.

III. Case of Water Ingress in the Cold Storage System

Cause of the Problem

Emergency Solution Measures

1. First, close all the suction and discharge valves of the compressors of all units as well as the oil circuit valves.
2. Take out the filter elements of the liquid supply system filter and the return gas system filter.
3. Make bags the size of the filters with gauze, put the water-absorbing silica gel into the bags, and then put them into the filter barrels.

Startup and Operation

1. Start one compressor and turn on the cold storage system to make the refrigerant circulate. If the expansion valve is blocked by ice, it can be thawed with hot water or a hot air blower.
2. Replace the silica gel repeatedly every 2 to 4 hours to absorb the water in the system.
3. After the overall operation is normal, replace the refrigeration oil, the oil filter, and the filter elements of the liquid supply and return gas systems. If necessary, replace them twice.

Shanghai KUB Refrigeration Equipment Co., Ltd.

Free Call Video Chat