Causes and Solutions of Ice Blockage, Dirt Blockage and Oil Blockage

Blockages in the refrigeration system mainly occur as ice blockages, dirt blockages, or oil blockages in the capillary tube, or as dirt blockages in the dryer - filter. After the refrigeration system is blocked, since the refrigerant cannot circulate, the compressor runs continuously for a long time, the inside of the box does not cool or cools slowly, and the condenser does not heat up.

The following is a detailed introduction to the specific content of the solutions to blockages in the refrigeration system.

Causes and Fault Phenomena of Ice Blockage
The occurrence of ice - blockage faults is mainly due to an excessive amount of moisture in the refrigeration system. As the refrigerant circulates continuously, the moisture in the refrigeration system gradually concentrates at the outlet of the expansion valve.

Because the temperature at the outlet of the expansion valve is the lowest, the water freezes and gradually increases. When it reaches a certain extent, the expansion valve is completely blocked, the refrigerant cannot circulate, and the cold storage does not cool.
The manifestation of ice - blockage in the refrigeration system is that it works normally in the initial stage. Frost forms in the evaporator, the condenser dissipates heat, the unit operates stably, and the sound of the refrigerant flowing in the evaporator is clear and stable. As the ice - blockage forms, the airflow can be heard gradually weakening and being intermittent. When the blockage is severe, the airflow sound disappears, the refrigerant circulation stops, and the condenser gradually cools down.
Due to the blockage, the exhaust pressure increases, the operating sound of the machine becomes louder. No refrigerant flows into the evaporator, the frosted area gradually becomes smaller, and the temperature gradually rises.

At the same time, the temperature of the expansion valve also rises, so the ice begins to melt, and at this time, the refrigerant starts to circulate again. After a while, the ice - blockage occurs again, forming a periodic on - off phenomenon.

Removal of Ice - Blockage Faults
The occurrence of ice - blockage faults in the refrigeration system is because there is an excessive amount of moisture in the system. Therefore, the entire refrigeration system must be dried. There are two treatment methods:

Causes and Fault Phenomena of Dirt Blockage
The formation of dirt - blockage faults is due to an excessive amount of impurities in the refrigeration system. The sources of impurities in the system mainly include: dust and metal debris during the manufacturing process of the cold storage, the oxide layer on the inner wall peeling off during pipeline welding, the inner and outer surfaces of each component not being cleaned thoroughly during the processing, dust entering the pipeline due to poor pipeline sealing, impurities in the refrigeration oil and refrigerant, low - quality desiccant powder in the dryer - filter. In addition, when welding the expansion valve and the dryer - filter, the nozzle of the expansion valve is also likely to be welded and blocked.
Difference between Ice Blockage and Dirt Blockage
After ice - blockage occurs for a while, the refrigeration can be restored, forming a periodic repetition of on - off, blocked and then unblocked, unblocked and then blocked. However, after dirt - blockage occurs, the refrigeration stops.

Removal Method of Dirt - Blockage Faults in the Expansion Valve
Use high - pressure nitrogen combined with other methods to blow out the dirt in the blocked expansion valve. After the expansion valve is unblocked, clean and dry each component in the refrigeration system and then reassemble and weld to eliminate the fault. If the blockage of the expansion valve is severe and the above method cannot eliminate the fault, then replace the expansion valve to remove the fault.

Oil - Blockage Faults and Faults of Other Pipeline Blockages
The main cause of oil - blockage in the refrigeration system is that the cylinder body of the compressor is severely worn or the clearance between the piston and the cylinder is too large.
The oil discharged with the compressor is discharged into the condenser and then enters the dryer - 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, a blockage is formed at the inlet of the filter, preventing the refrigerant from circulating normally, and the cold storage does not cool.
The reasons for blockages in other pipelines are: being blocked by welding materials during pipeline welding; or the replaced pipe itself is blocked when replacing the pipe but not detected. The above blockages are all caused by human factors. Therefore, when welding and replacing pipes, operations and inspections should be carried out as required to avoid man - made blockage faults.

Removal of Oil - Blockage Faults
The occurrence of oil - blockage faults indicates that there is too much refrigeration oil remaining in the refrigeration system, affecting the refrigeration effect or even preventing refrigeration. Therefore, the refrigeration oil in the system must be completely removed.
When the filter is oil - blocked, replace it with a new one. At the same time, use high - pressure nitrogen to blow out part of the refrigeration oil accumulated in the condenser. When passing nitrogen, an electric hair dryer can be used to heat the condenser.