The high-low temperature test chamber is a core device for testing the performance stability of materials and products under extreme temperature variations. Excessive temperature fluctuations in the chamber directly affect the reliability of test data. When temperature fluctuations exceed the standard range, a systematic troubleshooting process is necessary to pinpoint the fault and prevent misjudgment from escalating the problem.
The relay, as the core actuator in the temperature control circuit of the high-low temperature test chamber, directly affects the start-up and shutdown accuracy of the heating and cooling systems. Oxidation, adhesion, or coil burnout of the relay contacts can lead to delayed or uncontrolled execution of heating/cooling commands. During troubleshooting, the power supply should be disconnected, and the contact surface should be inspected for signs of burning. The oxide layer should be sanded off with fine sandpaper, cleaned with alcohol, and reinstalled. If the contacts are severely worn or the relay cannot reset, it must be replaced with a relay of the same specification, ensuring that the rated voltage and current parameters of the new relay match the equipment.
The controller is the "brain" of the high-low temperature test chamber, and its parameter settings and hardware status directly affect the temperature control logic. Inappropriate PID parameters (proportional, integral, derivative) settings can lead to overshoot or lag in the temperature regulation process. For example, an excessively high proportional gain can cause drastic temperature fluctuations, while an excessively long integral time can lead to accumulated temperature fluctuations. During troubleshooting, it's necessary to access the controller's operating interface to verify that the temperature setpoint and control accuracy parameters meet the test requirements. A "no-load test" should be performed to observe whether the controller can stably control the equipment temperature. If the parameters are set correctly but the temperature still fluctuates, the signal transmission line between the controller and the temperature sensor needs to be checked. If necessary, the signal cable should be replaced or a professional technician should be contacted to repair the controller's mainboard.
The compressor, as the core component of the refrigeration system, directly affects temperature stability under low-temperature conditions. Internal motor failure, bearing wear, or refrigerant leakage in the compressor can lead to decreased refrigeration efficiency and an inability to stabilize the temperature at the setpoint. During troubleshooting, the equipment should be started, and the compressor's operating sound should be listened to for smoothness. If abnormal noise or frequent starts and stops occur, a pressure gauge should be used to check the suction/discharge pressure. If the pressure is too low, it may indicate a refrigerant leak; the leak point should be located and an appropriate amount of refrigerant added. If the pressure is too high, it may indicate a blocked condenser or compressor overload; the condenser should be cleaned and the compressor load checked.
The temperature sensor, acting as the "eyes" for detecting the temperature inside the chamber, directly affects the accuracy of temperature measurement due to its position and condition. If the sensor probe is obstructed by the sample, near the heater, or has frost on its surface, the detected temperature will not match the actual temperature. During troubleshooting, check that the sensor probe is fixed in the center of the chamber to avoid localized temperature measurement deviations. Also, check for loose or oxidized sensor terminals and use a multimeter to check if the sensor resistance is within the normal range. If the sensor is damaged, replace it with the same model and perform temperature calibration.
The sealing performance of the high-low temperature test chamber directly affects its temperature holding capacity. If the door seal is aged, damaged, or the door latch is loose, outside air will seep in, disrupting the temperature balance within the chamber. During troubleshooting, close the chamber door and check if the seal is tightly fitted. Applying a small amount of silicone grease to the seal can enhance the sealing effect. Also, check that any openings in the chamber (such as test lead holes) are properly sealed to prevent airflow from affecting the temperature.
A malfunction in the airflow circulation system can lead to uneven temperature distribution within the chamber. If the circulating fan speed is insufficient, the blades are damaged, or the air duct is blocked by the sample, localized temperature differences will form, causing temperature fluctuations. During troubleshooting, the equipment should be started to observe whether the fan is operating normally. If the fan stops or the airflow is weak, check if the fan power cord is loose and replace the faulty fan if necessary. At the same time, clear any debris from the air ducts to ensure smooth airflow.
Excessive temperature fluctuations in the high-low temperature test chamber require multi-dimensional troubleshooting, including checks on relays, controllers, compressors, sensors, sealing performance, and airflow circulation. Users should regularly maintain the equipment, calibrate temperature sensors, clean the heat dissipation filter, and follow standard operating procedures to reduce the risk of temperature fluctuations at the source. If the problem persists after self-troubleshooting, contact the professional manufacturer for technical support to ensure long-term stable operation of the equipment.
