Analysis of Common Failures of Thermal Expansion Valves of Four Major Parts of Dongyuejin Brand Chiller

Low-temperature chiller | Air-cooled chiller | Screw-type chiller | Open chiller | Water-cooled chiller - Dongyuejin chiller Four-part thermal expansion valve Common failure analysis: As one of the four chiller refrigeration system, It can be seen that its skill should not be underestimated. The thermal expansion valve is composed of three parts: the valve body, the temperature sensing package, and the balancing pipe. It mainly plays the role of throttling, depressurizing and regulating the flow in the chiller refrigeration system. At the same time, it also has the functions of preventing the wet compression and the liquid blow protection of the compressor. And abnormal overheating function.

However, with the long service life of the chiller, or improper operation, it will cause failure. Today's analysis for everyone is the common failure of the expansion valve:
1, the thermal expansion valve is not small: This is mainly when the transmission rod in the maintenance, the extension is too long, so that the valve needle is not small. Or adjust the pre-tightening force of the spring is not enough, the valve pin hole is not small. It may also be that the temperature sensor is too far away from the outlet of the evaporator, or it is not insulated from the suction pipe and is affected by the high temperature outside.
2. The phenomenon of oil plugging has caused: when the heart-compressor of the chiller is in operation, if the selected compressor oil has different specifications, quantities and requirements, or the oil quality is poor, the evaporating temperature is lower than a certain temperature. The wax in the oil will separate out and block the filter or pinhole of the thermal expansion valve.
3, thermal expansion valve transmission rod is too short or bent: When the transmission rod is bent or too short, the diaphragm force can not be transmitted to the valve needle seat, the valve needle is always in the upward trend, the expansion valve is insufficient to open or can not be opened.
4. The thermal fluid filled in the thermal expansion valve thermal system leaks. When the working fluid in the thermal expansion valve temperature sensing system leaks, the force acting on the diaphragm will decrease and the thermal expansion valve will not open.
5, in the refrigeration system with Freon refrigerant, when containing water, it is easy to cause ice blocking at the thermal expansion valve.
6. The small filter on the inlet side of the thermal expansion valve is blocked, which means “dirty blockage”. It is recommended to replace the filter. If it is dirty at the orifice of the expansion valve, replace the entire expansion valve.

The thermal expansion valve achieves a pressure drop from the condensing pressure to the evaporating pressure, which directly determines the operating performance of the entire system. However, in actual work, the operation of the thermal expansion valve is often overlooked, making the thermal expansion valve a dead end in the maintenance of the equipment. Regular inspection and adjustment of thermal expansion valves has important implications for the operating life of refrigeration equipment, energy conservation, and reduction of operating costs.

This article from the Shenzhen Yuejin Refrigeration starting, reproduced please note the original URL: http://