Common faults and solutions of customized experimental muffle furnace

Common faults and solutions of customized experimental muffle furnace

1. Heating system malfunction
Unable to start or slow heating up
reason:
The power supply voltage is unstable or the fuse is blown.
Heating elements (silicon carbide rods, resistance wires) are aging or breaking.
Solid state relay malfunction, resulting in abnormal current transmission.
resolvent:
Check if the power supply voltage is stable (such as 220V/380V) and replace the blown fuse.
Use a multimeter to test the resistance value of the heating element (the cold resistance of the silicon carbide rod is usually 5-10 Ω). If it is abnormal, replace it.
Check the conductivity of the solid-state relay. If it is damaged, replace it with a component of the same model.
Large temperature fluctuations or overheating
reason:
Thermocouples (temperature sensors) are oxidized, offset, or damaged.
Improper setting of PID parameters resulted in the failure of temperature control system regulation.
Poor heat dissipation, blocked ventilation vents or faulty circulating fan.
resolvent:
Regularly calibrate thermocouples to ensure their correct installation position and good contact.
Adjust PID parameters (such as proportional, integral, and derivative values) to optimize temperature control response.
Clean the air vents and fans of accumulated dust to ensure smooth airflow.

2. Temperature control malfunction
The actual temperature deviates significantly from the set value
reason:
The thermocouple index does not match the temperature control instrument.
The insulation layer of the furnace is aging and the heat loss is severe.
Abnormal temperature control module, such as incorrect parameter settings or software malfunctions.
resolvent:
Check the compatibility between the thermocouple scale (such as K-type, S-type) and the instrument, and replace it if necessary.
Check the sealing and insulation material status of the furnace, and repair the aging parts.
Restart the device or restore factory settings. If the problem persists, test the PID controller.
Program steps cannot be executed properly
reason:
Program parameter errors, such as rapid heating rate or temperature setting exceeding device load.
System software malfunction causing program interruption or false alarm.
resolvent:
Check the temperature and time parameters in the program to avoid short-term significant temperature rise.
Restart the device or upgrade the control system firmware, and if necessary, contact technical personnel to repair the motherboard.

3. Mechanical structural failure
The furnace door is stuck or poorly sealed
reason:
The furnace door hinge is loose or obstructed by foreign objects on the track.
The aging and deformation of the sealing strip cause heat loss.
Door magnetic switch malfunction, false alarm ‘furnace door not closed’.
resolvent:
Tighten the hinge screws, clean the track of foreign objects, and apply high-temperature resistant grease.
Replace the aging sealing strip to ensure that the furnace door is tightly closed.
Test the sensitivity of the door magnetic sensor, clean the dust in the sensing area or replace the sensor.
Furnace leakage or abnormal atmosphere
reason:
Wear of furnace body joints or aging of sealing components.
Ventilation system malfunction, such as fan shutdown or filter material blockage.
resolvent:
Replace high-temperature resistant seals and repair worn joints.
Regularly check the fan and filter material to maintain uniform airflow.

4. Display and communication malfunction
No display or garbled text on the screen
reason:
Power board malfunction, such as capacitor damage or poor contact.
The screen cable is loose or the system crashes.
resolvent:
Check the stability of equipment power supply and eliminate power board faults.
After power failure, reconnect the display cable and press and hold the reset button to restart the device.
Data transmission with controller failed
reason:
Loose interfaces such as the nine pin serial port and aviation plug.
Aging or poor contact of communication lines.
resolvent:
Re plug and unplug the interface to ensure a secure connection.
Check the integrity of the circuit and replace the aging communication cable.

5. Security protection failure
Frequent triggering of over temperature protection
reason:
Poor heat dissipation leads to excessive internal temperature of the device.
The temperature control system is malfunctioning and unable to provide accurate temperature feedback.
resolvent:
Clean the heat dissipation port and ventilation system to ensure heat dissipation efficiency.
Reduce the heating rate or set the temperature in sections after restarting to avoid short-term overheating.
Leakage or insulation damage
reason:
The insulation layer of the heating element or power cord is damaged.
Poor grounding of equipment or high environmental humidity.
resolvent:
Use an insulation resistance meter to test the insulation of the circuit and repair damaged areas.
Ensure that the equipment is properly grounded and avoid use in humid environments.

Daily maintenance suggestions
Regular cleaning: Clean the oxide inside the furnace every month, and check the condition of heating elements and seals every quarter.
Calibration and testing: Calibrate thermocouples monthly and test the performance of ventilation systems and insulation materials annually.
Operation standard: Avoid overloading operation and set the temperature rise and fall rate reasonably; When placing samples in the furnace, power should be cut off first.
Environmental requirements: The equipment should be placed in a place free of conductive dust and corrosive gases, with an ambient temperature controlled between 0-40 ℃.