Jul 24, 2026
A KST thermostat is a temperature control switch commonly used in electric irons. Its primary function is to maintain the desired ironing temperature by automatically switching the heating element ON and OFF.
When the electric iron is plugged into the power supply, electricity flows through the KST thermostat to the heating element. The heating element begins converting electrical energy into heat.
Inside the KST thermostat is a bimetallic strip made from two different metals bonded together. Since the two metals have different coefficients of thermal expansion, the strip bends as its temperature increases.
As the soleplate temperature rises, the bimetal strip gradually bends toward the opening mechanism.
When the preset temperature is reached, the bending force of the bimetal strip causes the electrical contacts inside the thermostat to open. This interrupts the electrical circuit, stopping power to the heating element. The indicator lamp usually turns OFF at this point.
After power is disconnected, the soleplate gradually cools during use. As the temperature decreases, the bimetal strip returns to its original shape.
When the temperature falls below the preset level, the contacts close again, restoring power to the heating element. The indicator lamp turns ON, and the heating cycle repeats automatically.
The temperature control knob changes the mechanical position of the thermostat mechanism, which adjusts the contact opening point. This allows users to select different ironing temperatures for various fabrics, such as:
| Item | Specification |
|---|---|
| Product | KST Thermostat |
| Application | Electric Iron |
| Function | Automatic temperature control |
| Operating Principle | Bimetal thermostat with automatic ON/OFF switching |
| Temperature Control | Adjustable by temperature control knob |
| Temperature Range | Customized |
| Contact Type | Normally Closed (NC) |
| Operating Voltage | Customized |
| Rated Current | Customized |
| Temperature Accuracy | Customized |
| Reset Type | Automatic reset |
| Sensor Type | Bimetal strip |
| Switching Action | Opens circuit at set temperature and recloses after cooling |
| Mounting | Screw mounting to iron soleplate |
| Typical Applications | Dry iron, steam iron, travel iron, household electric iron |
This ON/OFF cycling maintains the soleplate temperature within a controlled range, ensuring safe and effective ironing performance.
Answer:
This is normal operation. The KST thermostat automatically switches the heating element ON and OFF to maintain the selected temperature. The indicator light turns ON when the iron is heating and turns OFF when the set temperature has been reached.
Answer:
Possible causes include:
Inspect the power source and temperature setting first. If the problem persists, the thermostat or heating element should be checked or replaced.
Answer:
This may occur if the KST thermostat is malfunctioning or incorrectly calibrated. A damaged bimetal strip or worn contacts may prevent the thermostat from switching properly, causing overheating or unstable temperature control. Replace the thermostat with the correct specification if necessary.
