A thermostatic expansion valve (TXV) is a small but essential component in HVAC systems. It controls the flow of refrigerant into the evaporator during the refrigeration cycle, ensuring efficient cooling. Most outdoor AC units use one TXV, while heat pumps may have two—one for the cooling cycle and another for heating.
How Does a Thermostatic Expansion Valve Work?
A thermostatic expansion valve (TXV) works by sensing the temperature and pressure of the refrigerant leaving the evaporator coil. Based on this data, it adjusts the flow of liquid refrigerant entering the evaporator. If the temperature rises, the TXV opens slightly to allow more refrigerant in. If it drops, the valve restricts the flow. This regulation ensures the refrigerant fully evaporates into vapor, preventing liquid from returning to the compressor and maintaining efficient system performance.
Here’s how it happens:
- The refrigerant-filled sensing bulb becomes the pressure detector by attaching it to the evaporator outlet.
- Temperature increases at the evaporator cause the pressure inside the sensing bulb to rise.
- As global pressure increases, the TXV starts its activation process to open the valve for additional refrigerant flow to the evaporator.
- Decreased outdoor temperatures create lower pressure inside the sensing bulb, leading the valve to move only slightly.
The buoyancy system uses its control system to maintain correct superheat levels, which prevent liquid refrigerant from reaching the compressor and, thus, protect an HVAC system.
What Is an Electronic Expansion Valve?
The advanced replacement solution exists by combining mechanical TXVs with electronic expansion valves (EEVs).
Electronic Expansion Valves differ from TXVs because their sensors and stepper motors operate to handle refrigerant flow regulations. The valves deliver excellent accuracy alongside quick control features that suit precision applications needing precise temperature management.
TXVs are installed in residential and commercial HVAC systems due to their straightforward design, even though their production price exceeds EEVs.
Types of TXVs
The form of TXVs depends on different applications and refrigerant requirements.
Internally Equalized TXV
Internal equalization within a TXV mechanism controls refrigerant flow using the pressure inside the evaporator coil. The device serves as equipment that operates with low pressure loss across coils, as it works well with straightforward HVAC systems.
Externally Equalized TXV
This particular TXV model has a separate equalizer line connecting to the evaporator outlet. Systems with significant coils or those that experience notable pressure drops should utilize this valve design, as it provides superior superheat control for improved operational results.
Adjustable TXV
During installation or servicing operations, technicians utilize adjustable TXVs to precisely adjust the superheat setting. A TXV valve offers adjustable performance ranges, allowing users to optimize their systems’ operating level according to specific conditions.
Non-adjustable TXV
The manufacturer provides pre-set TXV valves that require no manual user adjustments. A standard HVAC system requires these valves due to their simple installation process and their ability to maintain consistent operation without requiring user intervention.
Benefits of TXV in HVAC Systems
Your HVAC system receives these advantages when you introduce a TXV:
- The TXV system controls refrigerant flow based on active system needs, so the overall system saves unnecessary work.
- The TXV regulates superheat correctly to maintain a functioning evaporator coil at its best performance level.
- TXVs protect compressors from damage by stopping refrigerant liquids from reaching the compressor components, thus increasing the machine’s lifespan.
- Power Efficiency Improves because the system operates with the amount of refrigerant required, thus resulting in reduced utility expenditures.
- TXVs adjust their operation according to changing load requirements, making them ideal for systems with indoor-outdoor temperature variations.
TXV vs Fixed Orifice Devices
HVAC systems continue to employ fixed orifice devices, such as capillary tubes, as their refrigerant metering components. The fixed orifice remains easier to install and more affordable, yet it provides less precise control than TXV meters.
Steady refrigerant delivery, using a fixed orifice, remains unchanged even when demand changes result in system waste or structural damage. The TXV device provides automatic flow control, which results in superior system performance and enhanced system protection.
Signs of a Faulty TXV
Multiple problems will occur when the TXV stops working properly. Here’s what to look for:
- Inconsistent cooling
- High superheat readings
- Frozen evaporator coil
- Short cycling of the compressor
- Unusual hissing sounds from the valve
A professional examination of your HVAC system is necessary when you observe these warning signals.
Is a TXV Right for Your HVAC System?
TXV provides the best modern HVAC technology outcome during modernization and comfort optimization projects. Material testing valves are standard equipment in high-efficiency systems, as prominent manufacturers recommend their use to maximize system performance.
A certified technician will assess your system to supply customized recommendations about TXV HVAC installation when you are uncertain about its suitability.
Let All About Air Conditioning & Heating Help
All About Air Conditioning & Heating is a company dedicated to integrating state-of-the-art TXV technology into our HVAC installations and maintenance services. Our experts provide assistance for every upgrade project, performance check, and new installation effort.
At All About Air Conditioning & Heating, we recommend the use of thermosensitive valves due to their value in enhancing comfort and efficiency for our customers. When you install the optimal TXV, your HVAC system will provide efficient and constant cooling throughout the entire year.
Reach out to us now on our website and schedule your system inspection appointment. Your comfort is our priority!