What is an expansion valve? Why does an air conditioner’s expansion valve fail? What are the symptoms for an air conditioner expansion valve failure
Air conditioning systems all use an expansion valve (or similar component, called an orifice tube), which is designed to lower the refrigerant’s pressure. It is a simple component that has no moving parts but is essential to the operation of your car’s air conditioner.
Air conditioning systems are divided into two parts: the high pressure side and the low pressure side. The compressor is where the high pressure side begins and ends. The compressor is the low pressure side. It starts at the expansion valve. Both components serve similar functions but have opposite functions such as increasing or decreasing pressure.
The real question here is: Why is this loop necessary?
This is done to get the most out of the cooling effect of rapidly reducing the pressure with a high-pressure frigerant. Spray paint or lighter fluid can help you experience this effect. You will notice the cooling effect when you quickly empty the can. The expansion valve does the same thing by quickly reducing the refrigerant pressure. The refrigerant can be cooled by this process up to 32 degrees. The refrigerant is then sent to an evaporator, which cools the cabin air.
The compressor cools the refrigerant by pressingurizing it. The refrigerant is then sent to a condenser (a radiator-type device). The condenser converts some heat into liquid and transfers some heat to the atmosphere. Depending on the system design, high pressure fluid can be restricted by an expansion valve or tube. This restricts the coolant’s pressure and sends it to an evaporator (another type) of radiator. A fan blows cold air from the evaporator to the cabin. The refrigerant’s pressure drops, and the refrigerant evaporates. This cycle continues as long as there is an air conditioner running.
A/C systems all have a dryer that removes water from the lines. Expansion valves are equipped with receiver-type dryers. The filter, also known as the condenser, is located on the high pressure side. The dryer’s task is to separate liquid and gas, remove moisture, and filter dirt.
For systems that have an orifice tube, accumulator dryers are used. This component is located on a low pressure side of a system and is connected to the outlet for the evaporator. It stores the liquid refrigerant so it can’t get into the compressor.
The layouts of the system components can be seen in the image below, which includes the expansion valve as well as the orifice tub.
Why does the Expansion Valve degrade?
The operation of an air conditioner is dependent on the expansion valve. The expansion valve is critical to the operation of your air conditioner. If it fails, it will cause the system to stop functioning properly and not be able fulfill its purpose. If it becomes clogged, the only way that an expansion valve could fail is to stop working.
The expansion valve should not be blocked under normal conditions. The air conditioning system is closed and dirt cannot get in. If there is a leak, however, the refrigerant could become contaminated, and the expansion valve might become clogged. Wearing components can also cause the compressor to fail, which could lead to the valve becoming clogged. The expansion valve can also get clogged when low quality refrigerants are used or air conditioner leak stoppers are used.
Small particles are used to prevent leakages in the system. These particles can cause the expansion valve to block and the air conditioning system fail. The pressure test will determine if the expansion valle is damaged.
What are the Signs of Expansion Valve Failure
The expansion valve is susceptible to failure like any other component of an air conditioner system. You may experience the following symptoms if your expansion valve fails.
Hot Air Blow to the Air Conditioner
An ill-functioning expansion valve can cause hot air to be emitted by the air conditioner system. The A/C system won’t function properly if the valve is not closed. If the valve remains open, the evaporator of the A/C system will flood.
Ice on Evaporator and Grilles
Frosting should not be seen on vents or grilles no matter how cold the air conditioner blows. If frosting appears on the vents (vents / grilles), it is likely that the evaporator freezes. You will notice that the air coming from the vents is much colder then normal. Although this may sound like a good thing, if it continues, it can cause problems with the overall performance of your system.
A closed expansion valve can lead to the evaporator bursting, which can cause icing at its outlet. However, icing found on the outside or inside of the expansion valve can indicate that it is blocked or stuck in its closed position.
Air Conditioning System Oil or Paint Buildup
Leakage of the expansion valve is possible. You may also notice oil from the air conditioner accumulating around your valve. You may also notice phosphorescent dye if dye was added to the system.
Continuous Air Conditioning Compressor
The compressor will continue to run if the A/C expansion tube is not closed properly. Overloading the compressor can cause damage to other parts of the system.
Inconsistent airflow
Sometimes, an expansion valve that is not working properly can cause problems with the system’s refrigerant flow control. If this happens, the cabin’s air will alternate between warm and cold.
Cost of replacing an expansion valve can vary depending upon the make and model of your vehicle. To replace the expansion valve, it is necessary to drain the air conditioning system and refill it. While the cost of replacing the valve is low, the majority of repair costs are associated with labor.
