What are the common faults of electric heating tubes?

Common faults of electric heating tubes include decreased heating efficiency, leakage, short circuit, burnout, etc. The following is a detailed introduction:
Decrease in heating efficiency
Reason: Scaling on the surface of the heating tube affects heat transfer; insufficient power supply voltage leads to reduced heating power; aging of the heating tube, increased resistance, and decreased power.
Performance: The heating time is extended, and it takes longer than normal to reach the set temperature, or the set temperature cannot be reached.
Leakage
Reason: The insulation layer of the heating tube is damaged, which may be caused by long-term use, mechanical damage, high temperature aging, etc.; the terminal is damp or water-infiltrated, causing current leakage; the heating wire inside the heating tube is in contact with the outer shell.
Performance: When touching the heating tube or the equipment in contact with it, there will be a feeling of electric shock, or the leakage protection device will trip.
Short circuit
Reason: The heating wires are in contact with each other, which may be caused by improper installation, deformation of the heating tube, etc.; the insulation layer of the lead wire of the heating tube is damaged, resulting in a short circuit between the wires; external debris or liquid enters the heating tube, causing a short circuit.
Performance: After closing the circuit, the fuse is blown, or the air switch trips, and the circuit cannot work normally.
Burning
Reason: Long-term overload operation causes the current on the heating tube to exceed the rated value; quality problems of the heating tube, such as uneven material of the heating wire, poor welding, etc.; poor heat dissipation conditions, resulting in excessive temperature of the heating tube.
Performance: The heating tube stops working, and the resistance value becomes infinite, which can be found when measured with a multimeter.
Surface deformation or damage
Reason: The heating tube may deform due to thermal stress during heating and cooling; the surface of the heating tube is damaged by external impact or extrusion; the heating tube material is poor and easily deformed at high temperature.
Performance: The surface of the heating tube is bent, twisted, or has obvious cracks and damage.
Temperature control system failure
Reason: The temperature sensor fails and cannot accurately measure the temperature; the thermostat fails and cannot normally control the working state of the heating tube; the control circuit fails, such as relay damage, line break, etc.
Performance: Inaccurate temperature control, too high or too low temperature, or the heating tube cannot work according to the set temperature.