Summary of common failures of thermal expansion valves
Thermal expansion valves are a control element widely used in air conditioning, refrigeration and other fields, mainly responsible for realizing pressure regulation and flow control of refrigerants.
Many friends who do refrigeration know that thermal expansion valve failure is a common failure in refrigeration maintenance. The price of thermal expansion valves is not expensive, about two or three hundred yuan (CNY), but not all thermal expansion valve failures need to be replaced. Some minor problems can be solved by simple treatment. This article introduces the 5 common thermal expansion valve failures in refrigeration maintenance for reference.
1. Blockage
Failure manifestation: The flow of refrigerant is blocked, the refrigeration effect is poor, and even the system is shut down.
Cause analysis: The refrigerant contains impurities such as particulate impurities, oil or oxides, which cause the throttle or filter of the thermal expansion valve to be blocked.
Troubleshooting method: Clean the filter or replace the thermal expansion valve, and at the same time strengthen the cleaning and maintenance of the system to avoid impurities from entering.
2. Leakage
Failure manifestation: Refrigerant leakage, the cooling capacity of the system decreases, which may affect the stability and performance of the system.
Cause analysis: The valve seal ring is aged, damaged or improperly installed, resulting in refrigerant leakage.
Troubleshooting method: Replace the damaged seal ring or reinstall the thermal expansion valve to ensure good sealing.
3. Stuck
Fault manifestation: The thermal expansion valve cannot open and close normally, resulting in uncontrolled refrigerant flow, which may cause the evaporator to lack liquid or over-liquid problems.
Cause analysis: After long-term use, the valve core is stuck due to fouling, corrosion or wear inside the valve.
Troubleshooting method: Clean, derust or replace worn parts of the thermal expansion valve to ensure its normal opening and closing.
4. Failure of the temperature sensor package
Fault manifestation: The temperature sensor package cannot accurately monitor the evaporator outlet temperature, resulting in the thermal expansion valve being unable to correctly adjust the refrigerant flow.
Cause analysis: The temperature sensor package is filled with leakage, damage or loose joints, resulting in temperature signal distortion.
Troubleshooting method: Replace the damaged temperature sensor package to ensure that it can accurately measure the evaporator outlet temperature. At the same time, check the installation position and fixing method of the temperature sensor package to ensure that it is close to the suction pipe and avoids thermal resistance such as the insulation layer.
5. Inaccurate superheat control
Fault manifestation: The superheat is too high or too low, affecting the performance and stability of the refrigeration system.
Cause analysis: The superheat adjustment screw of the thermal expansion valve is improperly set, or the temperature sensor package is not installed in the correct position.
Troubleshooting method: According to the system design requirements, adjust the superheat adjustment screw to stabilize the actual superheat within the set value range. At the same time, check the installation position and fixing method of the temperature sensor package to ensure that it can accurately measure the evaporator outlet temperature and transmit the correct temperature signal.
Summary of common failures of thermal expansion valves
Thermal expansion valves are a control element widely used in air conditioning, refrigeration and other fields, mainly responsible for realizing pressure regulation and flow control of refrigerants.
Many friends who do refrigeration know that thermal expansion valve failure is a common failure in refrigeration maintenance. The price of thermal expansion valves is not expensive, about two or three hundred yuan (CNY), but not all thermal expansion valve failures need to be replaced. Some minor problems can be solved by simple treatment. This article introduces the 5 common thermal expansion valve failures in refrigeration maintenance for reference.
1. Blockage
Failure manifestation: The flow of refrigerant is blocked, the refrigeration effect is poor, and even the system is shut down.
Cause analysis: The refrigerant contains impurities such as particulate impurities, oil or oxides, which cause the throttle or filter of the thermal expansion valve to be blocked.
Troubleshooting method: Clean the filter or replace the thermal expansion valve, and at the same time strengthen the cleaning and maintenance of the system to avoid impurities from entering.
2. Leakage
Failure manifestation: Refrigerant leakage, the cooling capacity of the system decreases, which may affect the stability and performance of the system.
Cause analysis: The valve seal ring is aged, damaged or improperly installed, resulting in refrigerant leakage.
Troubleshooting method: Replace the damaged seal ring or reinstall the thermal expansion valve to ensure good sealing.
3. Stuck
Fault manifestation: The thermal expansion valve cannot open and close normally, resulting in uncontrolled refrigerant flow, which may cause the evaporator to lack liquid or over-liquid problems.
Cause analysis: After long-term use, the valve core is stuck due to fouling, corrosion or wear inside the valve.
Troubleshooting method: Clean, derust or replace worn parts of the thermal expansion valve to ensure its normal opening and closing.
4. Failure of the temperature sensor package
Fault manifestation: The temperature sensor package cannot accurately monitor the evaporator outlet temperature, resulting in the thermal expansion valve being unable to correctly adjust the refrigerant flow.
Cause analysis: The temperature sensor package is filled with leakage, damage or loose joints, resulting in temperature signal distortion.
Troubleshooting method: Replace the damaged temperature sensor package to ensure that it can accurately measure the evaporator outlet temperature. At the same time, check the installation position and fixing method of the temperature sensor package to ensure that it is close to the suction pipe and avoids thermal resistance such as the insulation layer.
5. Inaccurate superheat control
Fault manifestation: The superheat is too high or too low, affecting the performance and stability of the refrigeration system.
Cause analysis: The superheat adjustment screw of the thermal expansion valve is improperly set, or the temperature sensor package is not installed in the correct position.
Troubleshooting method: According to the system design requirements, adjust the superheat adjustment screw to stabilize the actual superheat within the set value range. At the same time, check the installation position and fixing method of the temperature sensor package to ensure that it can accurately measure the evaporator outlet temperature and transmit the correct temperature signal.
