Contact us to help you solve it effectively
1. Ice blockage
Ice blockage fault causes
The main reason is that there is excessive moisture in the refrigeration system. With the continuous circulation of the refrigerant, the moisture in the refrigeration system gradually concentrates at the outlet of the expansion valve. Since the temperature at the outlet of the expansion valve is the lowest, the water freezes into ice and gradually increases. When it reaches a certain level, it completely blocks the expansion valve and the refrigerant cannot circulate.
The main sources of moisture in the refrigeration system are:
- The motor insulation paper in the compressor contains moisture, which is the main source of moisture in the system.
- The moisture remaining in the components and connecting pipes of the refrigeration system due to insufficient drying;
- The refrigeration oil and refrigerant contain more moisture than allowed;
- During the assembly or maintenance process, the pipeline is in an open state for a long time, causing the moisture in the air to be absorbed by the motor insulation paper and refrigeration oil.
Due to the above reasons, the water content of the refrigeration system exceeds the allowable amount of the refrigeration system, resulting in ice blockage.
Impact of ice blockage on refrigeration system
On the one hand, ice blockage causes the refrigerant to be unable to circulate, and the refrigeration system cannot refrigerate normally; on the other hand, moisture will also react chemically with the refrigerant to generate hydrochloric acid and hydrogen fluoride, causing corrosion to metal pipes and components, and even causing insulation damage to the motor windings. At the same time, it will also cause the refrigeration oil to deteriorate and affect the lubrication of the compressor.
The manifestation of ice blockage in the refrigeration system is that it works normally in the initial stage, frost in the evaporator, heat dissipation in the condenser, the unit runs smoothly, and the sound of refrigerant activity in the evaporator is clear and stable. With the formation of ice blockage, the airflow can be heard to gradually weaken and intermittently. When the blockage is serious, the airflow sound disappears, the refrigerant circulation is interrupted, and the condenser gradually cools down.
Due to the blockage, the exhaust pressure increases, the machine operation sound increases, no refrigerant flows into the evaporator, the frosting area gradually decreases, the temperature gradually increases, and the expansion valve temperature also rises together, so the ice begins to melt, and the refrigerant begins to circulate again. After a period of time, ice blockage occurs again, forming a periodic pass-blocking phenomenon.
Elimination of ice blockage
Ice blockage occurs in the refrigeration system because there is excessive moisture in the system, so the entire refrigeration system must be dried. There are two ways to deal with it:
- Use a drying oven to heat and dry each component. This method is the most effective in eliminating ice blockage, but it is only applicable to the warranty of the cold storage manufacturer.
- Use heating vacuum and secondary vacuum methods to eliminate moisture from each component of the refrigeration system.
2. Dirt blockage
Cause of dirty blockage
It is caused by excessive impurities in the refrigeration system.
When the impurities and powder flow through the dry filter, most of them are removed by the dry filter. When there are more impurities in the dry filter, some fine dirt and impurities are brought into the expansion valve by the refrigerant with a higher flow rate, and are retained and accumulated in the part with greater resistance in the bending section of the expansion valve. The resistance is getting bigger and bigger, making it easier for impurities to be retained until the expansion valve is blocked and the refrigeration system cannot circulate.
In addition, the distance between the expansion valve and the filter in the dry filter is too close, which is also easy to cause dirty blockage; in addition, when welding the expansion valve and the dry filter, it is also easy to weld the expansion valve pipe orifice.
The impact of dirty blockage on the refrigeration system
When the refrigeration system is dirty and blocked, the refrigerant cannot circulate, causing the compressor to run continuously, the evaporator is not cold, the condenser is not hot, the compressor shell is not hot, and there is no sound of airflow in the evaporator.
If it is partially blocked, the evaporator feels cool or icy, but there is no frost. When you touch the outer surface of the filter drier and expansion valve, it feels very cold, frosted, and even a layer of white frost will form. This is because when the refrigerant flows through a slightly blocked filter drier or expansion valve, it produces a throttling and pressure reduction effect, causing the refrigerant flowing through the blockage to expand, vaporize, and absorb heat, resulting in condensation or frost on the outer surface of the blockage.
The difference between ice blockage and dirty blockage:
After a period of ice blockage, refrigeration can be restored, forming a cycle of sometimes unblocked, sometimes blocked, blocked and then unblocked. However, refrigeration cannot be performed after dirty blockage occurs.
Troubleshooting of dirty blockage
- Use high-pressure nitrogen combined with other methods to blow out the dirt in the blocked expansion valve;
- After the expansion valve is blown through, clean and dry all parts in the refrigeration system and reassemble and weld them to eliminate the fault.
- If the expansion valve is seriously blocked, replace the expansion valve to eliminate the fault.
3. Oil blockage and other pipeline blockage
Oil blockage fault cause
The compressor cylinder is seriously worn or the clearance between the piston and the cylinder is too large.
The cause of other pipeline blockage is:
The pipeline is blocked by solder during welding; or when the pipe is replaced, the pipe itself is blocked without being discovered. Therefore, it is required to operate and check as required when welding and replacing the pipe, so as not to cause artificial blockage.
The impact of oil blockage on the refrigeration system
The gasoline discharged from the compressor is discharged into the condenser, and then enters the drying filter together with the refrigerant. Due to the high viscosity of the oil, it is blocked by the desiccant in the filter. When there is too much oil, it forms a blockage at the filter inlet, so that the refrigerant cannot circulate normally and the refrigeration system does not refrigerate.
Troubleshooting of oil blockage
There is too much refrigeration oil remaining in the refrigeration system, which affects the refrigeration effect or even fails to refrigerate. Therefore, the refrigeration oil in the system must be cleaned.
When the filter is blocked by oil, a new filter should be replaced, and high-pressure nitrogen should be used to blow out part of the refrigeration oil accumulated in the condenser. When nitrogen is introduced, a hair dryer can be used to heat the condenser.
Contact us to help you solve it effectively
Post time: Jun-04-2025
