Several methods can be used to determine if the temperature sensor of a hot air circulation oven is working properly:
Observing the Temperature Display and Actual Conditions
- Comparing the displayed temperature with the ambient temperature: When the oven is not heating, use a calibrated high-precision thermometer to measure the actual ambient temperature inside the oven, and simultaneously check the temperature displayed on the instrument connected to the temperature sensor. The two values should be basically consistent, with the difference generally within the instrument's accuracy range.
- Observing temperature changes during the heating process: Turn on the oven's heating function and observe the temperature rise displayed by the temperature sensor. Under normal circumstances, the temperature should rise steadily and match the set heating rate. If the temperature rises slowly, stagnates, or fluctuates significantly, the temperature sensor may be malfunctioning.
Checking the Sensor's Appearance and Installation
- Checking the sensor probe: Open the oven door and check if the temperature sensor probe is damaged, deformed, loose, or detached. If there is dirt or impurities on the probe surface, it may affect its temperature sensing performance and needs to be cleaned.
- Confirming the installation position: Ensure that the temperature sensor probe is installed in the correct position, usually in the central area of the oven or in a position that can accurately reflect the temperature of the materials. It should not be in direct contact with heating elements, air ducts, etc., to avoid being affected by local high temperatures or strong airflow.
Measuring The Sensor's Output
- Using a multimeter to measure resistance or voltage: Depending on the type of temperature sensor, use a multimeter to measure its resistance value or output voltage. At different temperatures, the sensor's resistance or voltage should be within the corresponding standard range. If the measured value differs significantly from the standard value, the sensor may be damaged.
- Checking the sensor's signal lines: Use the continuity test function of a multimeter to check whether the power and signal lines of the temperature sensor are open or short-circuited. If there are problems with the wiring, it will also cause the sensor to malfunction.
Using the Substitution Method for Testing
- Replacing the sensor: If a spare temperature sensor of the same model is available, it can be replaced in the oven for testing. If the temperature display and control return to normal after replacement, it indicates that the original sensor was faulty.
- Using other temperature measuring equipment: Other professional temperature measuring equipment such as thermal imagers and thermometers can be used to measure the temperature at different locations inside the oven while it is running, and compare it with the temperature displayed by the temperature sensor. If there is a significant difference between the two, the temperature sensor may be inaccurate.
Checking The Control System
- Checking the control instrument status: Observe the working status of the temperature control instrument and check for any abnormal displays such as alarm prompts or error codes. Also, check if the instrument's parameter settings are correct, such as the set temperature and alarm temperature.
- Checking the connection between the heating system and the sensor: Check if the heating system is working properly, as a heating system malfunction can also lead to abnormal temperature sensor readings. For example, a damaged heating element or a faulty relay may prevent the actual temperature inside the oven from rising, while the sensor displays normal operation. The entire heating system needs to be checked.