5 Common Reasons for Solenoid Valve Sticking in High-Temperature Environments
In air conditioning systems, clean room heating and cooling control devices, or process equipment operating in high-temperature environments, solenoid valves are crucial components for automatic opening and closing and precise flow control.
However, under long-term high-temperature operation, many users encounter problems such as "sluggish operation," "sticking and failure to return to position," and "unreliable opening and closing" of solenoid valves.
These phenomena may seem sporadic, but they are actually traceable. This article summarizes five common reasons for solenoid valve sticking in high-temperature conditions, for the reference of engineering maintenance personnel.
1. Excessive Coil Temperature Rise Leading to Piston Expansion and Sticking
When the solenoid valve is energized for a long time or installed near a high-temperature pipe section, the coil temperature rise, combined with the ambient heat, causes the internal temperature to exceed the rated value.
After the metal piston expands due to heat, the gap between it and the guide sleeve decreases, increasing friction until it sticks.
Symptoms: The coil surface is hot to the touch, the valve operates silently, or requires tapping to return to its original position.
Suggested Solutions:
• Use a high-temperature resistant solenoid valve (coil temperature resistance ≥180℃);
• Install an insulation layer or increase the distance between the valve body and the heat source;
• Avoid prolonged energized states.
2. Impurities in the Medium Causing Valve Core Sticking
When cooling water, steam, or process gas contains iron filings, sand, or scale particles, these impurities easily deposit on the valve core and sealing surfaces.
Under high-temperature conditions, the impurities harden and form scale, preventing the valve core from sliding smoothly.
Symptoms: The valve operates normally initially, but gradually malfunctions after a period of operation.
Pilot-operated solenoid valve
Suggested Solutions:
• Install a stainless steel filter upstream of the solenoid valve;
• Regularly clean the inside of the valve body;
• If the operating conditions involve frequent starts and stops, it is recommended to use a pilot-operated structure.
3. Aging and Deformation of Rubber Seals
Ordinary nitrile rubber (NBR) seals are prone to aging, hardening, or losing elasticity in high-temperature environments.
When the seal deforms, the movement of the valve core is hindered, resulting in sticking or leakage.
Symptoms: The valve body temperature is not high, but the valve core movement is not smooth, and there is a slight leakage sound. Suggested Solutions:
• Replace with fluororubber (FKM) or polytetrafluoroethylene (PTFE) seals;
• Check the flatness of the seal seat to avoid local pressure deformation.
4. Unstable Voltage or Coil Aging
Large fluctuations in the control power supply or aging of the coil insulation layer can lead to insufficient suction, preventing the valve core from fully engaging.
Symptoms: A "click" sound is heard when power is applied, but the valve does not operate, or operates intermittently.
Suggested Solutions:
• Check if the power supply voltage is within the rated range;
• Measure the coil resistance; replace the coil if it is aged or discolored;
• Install a voltage regulator module in the control cabinet.
5. Improper Installation Position or Direction
Some solenoid valves have strict requirements for installation direction (especially direct-acting structures). If the valve body is not level or the arrow direction is incorrect, gravity can affect the return of the valve core.
Symptoms: The valve operates normally when power is applied, but does not return to its original position or is delayed after power is removed.
Suggested Solutions:
• Install according to the direction indicated in the product instructions;
• Avoid inverted or tilted installation;
• Install independent supports for valves requiring frequent maintenance to reduce vibration stress.
6. Summary
The jamming problem of high-temperature solenoid valves mostly stems from five factors: heat, contamination, pressure, electricity, and installation.
Under high-temperature conditions, proper selection and regular maintenance are equally important.
