What is the construction and purpose of expansion valves?

Expansion valves are air conditioning system elements most often mounted at the evaporator, between the high and low-pressure sides. A typical valve consists of a body, flow channels, connections, and a part regulating the amount of refrigerant. Their purpose is to controlledly reduce the refrigerant pressure and dose it to the evaporator in an amount appropriate for operating conditions.

What are expansion valves used for?

Expansion valves are used to regulate the flow of refrigerant so that the evaporator can effectively extract heat from the air entering the cabin. As a result, the system maintains stable cooling, and the compressor does not work under unnecessary load. Improper operation of this element can cause weak cooling, evaporator freezing, or unstable air conditioning operation.

What is the construction and function of an evaporator in an air conditioning system?

The evaporator is a heat exchanger usually placed in the blower housing, to which the refrigerant flows after passing through the expansion valve. It consists of thin channels and fins that increase the cooling surface area. Its function is to extract heat from the air directed into the vehicle interior and to drain the moisture generated during cooling.

How to select expansion valves for a specific car?

It is safest to compare the OEM part number, interchangeable numbers, and mounting method. It is also worth checking the air conditioning system version, mounting location, connection type, and compatibility with a specific evaporator. For cars with different equipment, verification by VIN is helpful.

What symptoms indicate a problem with an expansion valve?

Common symptoms include weak cabin cooling, irregular air conditioning operation, and evaporator freezing. Incorrect system pressure and increased compressor load may also occur. Such symptoms should be evaluated together with the condition of the lines, receiver drier, and refrigerant level.

What data in the offer should be paid attention to before purchase?

Information about the brand, part condition, OEM part number, interchangeable numbers, vehicle placement, and fuel type is useful if the manufacturer distinguishes equipment versions. It is good to also check photos of the connections and body, as the valve shape often depends on the body version and evaporator housing. The more accurate the data comparison, the easier it is to match the part to the car.

Expansion valves

At Global Parts, we offer a wide selection of original used car parts, including expansion valves for many popular car brands such as BMW, Mini, Mercedes, Audi, Volkswagen, and others. Our expansion valves undergo quality control to ensure you receive a top-quality product.

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