Poor cooling effect means that the cold storage can operate normally, but the temperature in the storage does not drop to the set temperature under the specified working conditions. The reasons for this situation with refrigerants are as follows, and we have compiled the corresponding solutions for everyone.
1. Leakage of refrigerant
After the refrigerant leaks in the system, the cooling capacity is insufficient, the suction and exhaust pressures are low, and the intermittent “squeaking” airflow sound much louder than usual can be heard at the expansion valve. The evaporator has no frost or a small amount of frost on the corners.
If the expansion valve hole is enlarged, the suction pressure will not change much. After the shutdown, the equilibrium pressure in the system is generally lower than the saturation pressure corresponding to the same ambient temperature.
Solution: After the refrigerant leaks, do not rush to fill the system with refrigerant, but immediately find the leakage point, and fill it with refrigerant after the repair. The refrigeration system adopting an open-type compressor has many joints and many sealing surfaces, correspondingly more potential leakage points.
During maintenance, attention must be paid to exploring the easy-to-leak links, and according to experience, finding out whether there is oil leakage, pipeline breakage, loose joints, etc. at a major leakage point.
2. Too much refrigerant is charged after maintenance
The amount of refrigerant charged in the refrigeration system after maintenance exceeds the capacity of the system, the refrigerant will occupy a certain volume of the condenser, reduce the heat dissipation area, and reduce the cooling effect. The suction and discharge pressures are generally higher than normal pressures. The evaporator is not frosting, and the temperature in the warehouse is slow.
Solution: According to the operating procedure, the excess refrigerant must be discharged at the high-pressure shut-off valve after a few minutes of the shutdown, and the residual air in the system can also be discharged at this time.
3. There is air in the refrigeration system
Air in the refrigeration system will reduce the refrigeration efficiency. When the prominent phenomenon is air, exhaust pressure and exhaust temperature all increase.
Solution: A few minutes after shutdown, air can be discharged from the high-pressure shut-off valve several times in succession, and some refrigerants can be properly filled according to the actual situation.
4. Low compressor efficiency
The low efficiency of the refrigeration compressor means that under the condition that the working conditions remain unchanged, the actual displacement decreases and the refrigeration capacity decreases accordingly. This phenomenon mostly occurs on compressors that have been used for a long time. The wear is large, the matching gap of each part is large, and the sealing performance of the gas valve decreases, which causes the actual displacement to decrease.
Solution: Close the suction shut-off valve and let the compressor run for a few minutes, discharge the refrigerant in the crankcase into the condenser, stop the machine and immediately close the exhaust valve, and install high-pressure valves on the bypass holes of the suction and exhaust shut-off valves.
Loosen the connection of the bypass hole of the suction shut-off valve to allow air to be slowly sucked into the compressor so that the pressure in the discharge chamber of the compressor rises slowly, and the pressure rises to 1.MPa, tighten the buckle to stop the suction of air and allow The compressor will continue to run for a few minutes and stop for a few minutes, and stop for 10 minutes, depending on the recovery of the low-pressure vacuum. If the high and low pressures are balanced within 10 minutes, it means that the valve plate has serious leakage.
5. The frost on the surface of the evaporator is too thick
The cold storage evaporator used for a long time should be defrosted regularly. If it is not defrosted, the frost layer on the evaporator pipeline will become thicker. When the entire pipeline is wrapped into a transparent ice layer, it will seriously affect heat transfer and cause the temperature inside the storage room. It is not within the required range.
Solution: Stop defrosting, and don't knock the frost layer with ironware, wooden sticks, etc., to prevent damage to the evaporator pipeline.
6. There is refrigerating oil in the evaporator pipeline
During the refrigeration cycle, some refrigerating oil remains in the evaporator pipeline. After a long period of use, when there is a large amount of residual oil in the evaporator, it will seriously affect the heat transfer effect and cause poor cooling. If the white frost on the evaporator is incomplete and unreliable, and no other faults are found at this time, it may be mostly because of the poor cooling effect caused by oil.
Solution: Remove the refrigerant coil in the evaporator. Remove the evaporator, blow it out, and then dry it. If it is not easy to disassemble, use a compressor to pump air from the entrance of the evaporator, and then use a blowtorch to dry it.
7. The refrigeration system is not unblocked
As the refrigeration system is not cleaned, after a certain period of use, dirt will gradually accumulate in the filter, and part of the mesh will be blocked, resulting in a decrease in refrigerant flow and affecting the refrigeration effect. In the system, the expansion valve and the filter at the suction port of the compressor are also slightly blocked.
Solution: Clean up the dirt accumulated in the filter and unblock the blocked mesh.
Inferior refrigerants will also have poor cooling effects during the application process. Therefore, we must consider many things when choosing refrigerants. FOTECH, as an expert in refrigerant research for many years, is undoubtedly your best choice.
FOTECH is a professional manufacturer of refrigerants and fluoropolymers. Our refrigerant gases have outstanding performance in household, industrial and commercial refrigerant systems. Our products have passed various safety certifications, and the quality of the products has also been fully controlled. At the same time, we put the needs of customers first and can provide customers with thoughtful one-stop service. If you are interested in our refrigerants, please contact us immediately!