Since the UAE experiences high temperatures in summer, it gets difficult to travel without an air-conditioned car. Talking about car air-conditioning systems, the expansion valve in a car is a major control component of the AC loop. The expansion valve is also referred to as a metering device as it controls the amount of refrigerant released into the evaporator. Let’s find out all about the expansion valve in the car AC system.
What Does an Expansion Valve Do?
An expansion valve manages how much refrigerant liquid goes through the air conditioning system. It is one of the major parts of a car’s AC system. When there is excess refrigerant, the evaporator’s core gets cold and freezes. Similarly, when the core overheats the refrigerant gets low. This is where the expansion valve comes into play and controls the flow of refrigerant based on the evaporator’s temperature.
How Does an Expansion Valve Work?
A rod located inside the AC expansion valve controls the refrigerant’s flow. The pathway for the refrigerant can be closed or opened by moving the rod up or down, respectively. The refrigerant can move through if the pathway is opened, and vice versa. More refrigerant flows through the tube when the car AC is set to a higher temperature, making the air cooler.
The AC expansion valve acts mainly as a metre when regulating the refrigerant flow. In simple words, based on the temperature demands, the valve determines how much refrigerant needs to flow down the channel. That said, if you are a resident of the UAE, make sure you get your car’s AC maintained timely to tackle the hot weather while driving.
Types of Expansion Valves in Car AC
There are several types of expansion valves, but they all operate on the same core principle. The valve stays open to permit refrigerant flow until the evaporator’s temperature falls to a specific level. The valve then closes to stop the evaporator from freezing and superheating. In automotive, thermal expansion valves (TEVs) are commonly used.
What is a Thermal Expansion Valve?
A thermal expansion valve is also known as a thermostatic expansion valve. It is usually abbreviated as TXV, TEV, or TX valve. A thermal expansion valve controls the quantity of refrigerant released into the evaporator and regulates the vapour’s superheat leaving the evaporator.
That said, the thermostatic valve does not regulate temperature. The temperature varies with the evaporation pressure. Despite that, they are well-known due to their accessibility, simplicity, and high sensitivity and precision in regulation. There is a wide variety of thermal expansion valves, covering an extensive range of capacity and temperature.
Types of Thermal Expansion Valves
The thermal expansion valves are of two main types; externally or internally equalised valves. The difference is based on how the evaporator pressure affects the needle’s position. For automotive applications, externally equalised valves are used.
Symptoms of a Bad Expansion Valve
The symptoms of a bad expansion valve can result in car AC issues. The common bad car AC expansion valve symptoms are detailed below.
1. Warm Air from Vents
Warm air blowing from car AC vents indicates that the refrigerant is unable to flow properly through the system. This is one of the most common symptoms of a faulty expansion valve.
2. Frost on the Vents
Frost on air vents is an indication of a bad expansion valve. The air from the vent is colder than normal. This results due to an overflow of refrigerant throughout the system as the expansion valve stops working.
3. AC Compressor Always Working
A bad AC expansion valve can remain open consistently, resulting in a continuous flow of refrigerant into the car AC system. The compressor keeps on pumping the refrigerant increasing stress on it. It is also one of the causes of car AC failure.
4. Inconsistent Airflow
Another symptom of a bad expansion valve is inconsistent airflow from car AC. This happens because the valve is no longer able to regulate the refrigerant’s flow throughout the system.
You may observe the air from the vent is either too cold or too warm. It switches back and forth between different temperatures at different time intervals. It is suggested to inspect the AC expansion valve immediately upon noticing the fluctuation in airflow.
5. Car AC system failure
If the above symptoms are not treated for long, they can damage other parts of a car’s AC system. This will eventually fail the car’s AC system.
That is all about the expansion valve in the car ac system. Make sure to get your car maintained timely as per the car maintenance schedule. Despite being regularly maintained, if your car is still posing issues, it is better to switch to another one. Explore these used cars for sale in the UAE if you wish to switch to a modern car with high-tech features.
Stay tuned to the UAE’s leading auto blog for more information regarding car parts and accessories.
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