Summary of common problems in cold storage Sep 01, 2021

The installation of refrigeration system equipment and refrigerant pipelines, even the overall design of the cold storage and the daily use of the cold storage, must be done in strict accordance with the specifications. Any irregular design, installation, or use or maintenance will cause the refrigeration system to operate. Bad, and even cause malfunction and damage to the machine.

Condensing unit production base

1. The refrigeration compressor unit has no vibration reduction installation, or the vibration reduction effect is not good
According to the installation specifications, the overall vibration damping device of the unit should be installed. If the damping is not standardized or there is no damping measure, the machine will vibrate violently, which will easily cause pipeline vibration, equipment vibration, or even machine room vibration.
2. No or lack of oil return bend in refrigerant pipeline
When the pipeline conveying refrigerant turns from the lateral direction to the upward curve, it must be made into a small bend that first hangs down and then upwards, that is, a U-shaped bend, so that the pipeline is qualified if it goes upward, and it cannot be directly turned into a 90-degree upward curve. Otherwise, the oil in the system will not be able to return to the compressor well, and a large amount of oil will be deposited in the air cooler, which will make the fan and the entire system not function properly, or even damage the fan and unit equipment.
3. Unbalanced refrigerant pipeline connection
When the unit pipeline is connected to a group of multiple compressors, in order to distribute the oil return to each compressor in a balanced manner, the main pipeline interface must be set in the middle of the multiple heads, and then branch pipes should be installed on both sides. To allow the return oil to flow into multiple compressor branch pipes in a balanced manner.
Moreover, each branch pipe should be equipped with valves to adjust the amount of oil return. If this is not the case, but multiple downward branch pipes are drawn from different parts of the main pipeline to connect to multiple compressors, there will be uneven oil return. The first oil return is always the most full, and the latter one in turn As the oil return gradually decreases. In this way, the first compressor may have operating failures, huge vibrations, excessive oil pressure, and overheating of the unit, resulting in accidents such as compressor cylinder flushing/locking, and damage to the equipment.

4. The pipeline is not insulated
If there is no thermal insulation material, the cold pipeline will be frosted at the ambient temperature, which will affect the cooling effect, increase the load of the unit, and then make the unit super-intensive operation and reduce the service life of the unit.
5. It is necessary to check various technical indicators regularly and adjust in time
The operating temperature and pressure of the system, the amount of lubricating oil and refrigerant must be checked and adjusted in time. The system should have automatic control and compressor alarm devices. Once there is a problem, an alarm will be issued, or an automatic protective shutdown and the compressor will stop.

6. Maintenance of the condensing unit
The lubricating oil and filter should be replaced regularly. Replenish refrigerant as needed. The condenser should be cleaned at any time and kept clean to avoid dust, sand or flying debris, which will affect the cooling effect. Some people think that lubricating oil can continue to be used as long as it has no impurities, although it has been used for more than two years, it does not need to be replaced. This is obviously wrong. If the lubricating oil has been running for a long time under high temperature in the system, its performance may have changed, and it can no longer play the role of lubrication. If it is not replaced, it will increase the operating temperature of the machine and even damage the machine.
The filter should also be replaced regularly. We know that general machines have "three filters" and they must be replaced regularly. The refrigeration compressor system may not have "three filters", only one oil filter, and it should be replaced regularly. If you think that the filter is metal, it does not need to be replaced if it is not damaged. This view is groundless and untenable.

Heat pump water heater

7. The installation environment and maintenance of the evaporator for cold storage
The location and environment of the air cooler inside the cold storage will affect its operation. Generally, the air cooler near the cold storage door is prone to condensation and frost. Because its environment is at the doorway, hot air flows outside the door when the door is opened, and when it encounters the air cooler, condensation and frost, or even icing, will occur. Although the air cooler can automatically heat and defrost at regular intervals, if the door is opened too frequently, the opening time is too long, and the time and quantity of hot air entering is long, the defrosting effect of the fan is not good. Because the defrosting time of the air cooler cannot be too long, otherwise the cooling time will be relatively shortened, the cooling effect will not be good, and the storage temperature cannot be guaranteed.
In some cold storages, due to too many doors, the opening frequency is too high, the time is too long, there is no insulation measures at the door, and there is no partition wall inside the door, so that the cold and hot air flows between the inside and outside are directly exchanged, and the air cooler near the door will inevitably encounter serious problems. Frost problem.

Cold storage evaporator

8. Drainage of the melted water during the defrosting of the evaporator for cold storage.
This problem is related to the severity of frosting. Due to the severe frost of the fan, a large amount of condensate will inevitably be produced. The fan's drain pan cannot bear it, and the drainage is not smooth. In this case, a drain pan can be installed and a thicker guide tube can be installed to remove the condensed water.
Some evaporators for cold storage have the problem of blowing water from the fan and spraying it onto the stock in the warehouse. This is also the frosting problem of the fan in the cold and heat exchange environment, mainly due to the condensed water generated by the fan leaf in the hot environment, rather than the problem of the defrosting effect of the fan itself. To solve the fan condensate problem, the environment must be improved. If there is a partition wall in the Kumen in the design, the partition wall cannot be cancelled. If the partition wall is removed to facilitate the entry and exit of goods and the environment of the fan changes, the cooling effect will not be achieved, the defrosting effect will not be good, and even frequent fan failures and equipment problems will occur.
9. The problem of the condenser fan motor and the electric heating tube of the air cooler.
This is a vulnerable part. The fan motor that runs for a long time in a high temperature environment may malfunction and be damaged. If the guaranteed temperature of the cold storage is very important, some vulnerable parts should be ordered for timely maintenance. The electric heating pipe of the air cooler also needs spare parts to be more safe.
10. The problem of cold storage temperature and cold storage door
A cold storage room, the area, the amount of inventory, how many doors are opened, the time and frequency of opening and closing of the doors, the frequency of inventory in and out, and the throughput of goods are all factors that affect the temperature in the warehouse.
11. Fire safety issues in cold storage
The cold storage is generally around minus 20 degrees. Due to the low ambient temperature, it is not suitable to install a fire sprinkler system. Therefore, more attention should be paid to fire prevention in cold storage. Although the ambient temperature of the cold storage is low, if a fire occurs, there are combustibles in the storage, especially the inventory is often packed in cartons and wooden boxes, which is easy to burn. Therefore, the risk of fire in cold storage is also great, and fireworks must be strictly prohibited in cold storage. At the same time, the air cooler and its wire box, power cord, and electric heating pipe must be checked frequently to eliminate electrical fire hazards.
12. The ambient temperature of the condenser for cold storage
The condenser is generally installed on the roof of the outdoor building. In the environment with high summer temperature, the temperature of the condenser itself is very high, which increases the operating pressure of the unit. If there is a lot of hot weather, you can add a pergola on the roof condensation to block the sun and reduce the temperature of the condenser, so as to reduce the pressure of the machine, protect the unit equipment, and ensure the temperature of the cold storage. Of course, if the unit capacity is sufficient to ensure the storage temperature, there is no need to build a pergola. The installation of refrigeration system equipment and refrigerant pipelines, even the overall design of the cold storage and the daily use of the cold storage, must be done in strict accordance with the specifications. Any irregular design, installation, or use or maintenance will cause the refrigeration system to operate. Bad, and even cause malfunction and damage to the machine.
The above information was summarized and edited by the KITDOO engineering team.

Condenser production base

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