A thermostatic expansion valve is a metering device that controls the amount of refrigerant that enters an air conditioner’s evaporator. Proper flow of refrigerant into the evaporator is essential for the proper cooling operations of an air conditioner.
Understanding the Cooling Process of an Air Conditioner
In order to produce cold air, an air conditioner has five essential components: refrigerant, compressor, evaporator, condenser, and throttling device. Air conditioners produce cold air thanks to a closed-loop system that first involves the refrigerant, in its gaseous form, getting compressed in the compressor. The compressor turns the refrigerant into a high-temperature, high-pressure gas that is then sent to the condenser that is located outside.
Once in the condenser, the air outside will absorb the heat from the refrigerant. This causes the refrigerant to decrease in temperature, which changes it to a liquid state. At this point, the refrigerant is very cold. Once the refrigerant changes to its liquid state, it starts to make its way to the evaporator. But before it goes into the evaporator, it is “metered” through the thermostatic expansion valve.
The thermostatic expansion valve controls the amount of pressure at which the liquid refrigerant enters the evaporator. This optimizes the process and is what makes air conditioning possible.
A blower fan brings in warm air from your home and blows it over the evaporator. The refrigerant in the evaporator absorbs the heat from the air, leaving the air cold. Another fan then blows the cold air into your ductwork, where it is distributed throughout your home. As the refrigerant absorbs the heat from the air, it begins to turn back into a gas and starts the process all over again by going back to the compressor.
Signs of a Malfunctioning Thermostatic Expansion Valve
Profession HVAC technicians use the following criteria to diagnose a malfunctioning thermostatic expansion valve:
- System not producing cold air
- Compressor has low amp draw
- System is short cycling on low pressure
- Condenser has low pressure
- Frost on the evaporator
- Compressor won’t turn off
These signs are also common among other issues that an HVAC system may have. That is why it is essential to hire an experienced company to troubleshoot and repair your system. A malfunctioning thermostatic expansion valve is the most misdiagnosed issue when it comes to HVAC systems. If it is misdiagnosed by an inexperienced technician, you might end up calling for repairs multiple times and wasting money before the real issue is fixed.
Common Causes of a Malfunctioning Thermostatic Expansion Valve
The most common cause of a malfunctioning thermostatic expansion valve is dirt or water making its way in the system and causing the valve to either get stuck open or closed. When it gets stuck open, the evaporator is flooded with refrigerant. When it gets stuck closed, not enough refrigerant makes it into the evaporator. These both result in the same thing; the system will not be able to produce an adequate amount of cooled air, and warm air will be coming through the vents.
This could result in the system running continuously. This not only increases your energy consumption and wear and tear on the system but can also cause the system to freeze up. This, in turn, can ruin your compressor, which is a very expensive fix.
The best way to avoid all of this is by scheduling regular maintenance for your system. An experienced HVAC technician will check all working components, clean the internal workings, and lubricate all moving parts. They will then test it to ensure that everything is running properly and at the correct pressure.
Ensure that new installations are done by a professional who knows what they are doing and backs their work with a warranty. A thermostatic expansion valve can malfunction because of the improper installation of other parts. If it goes undetected for too long, the damage it can cause to other parts of the system can cost nearly half as much as a new system.
Professional HVAC Experts That You Can Trust
For over 30 years, Galbreath Air has been providing the residents of Richmond Hill with the best heating and cooling services. Quality work is at the forefront of our business, which is why we offer a 100% satisfaction guarantee. In addition to heating and cooling services, we also offer indoor air quality solutions and a full range of ductwork services. Call us today to learn more about our services and to schedule an appointment.