Cartridge heaters may have various failures during long-term high-temperature operation, affecting the normal operation of equipment. Based on a large number of industry maintenance cases, summarizing common failure causes and corresponding troubleshooting methods can help quickly locate problems, reduce equipment downtime, and restore production in a timely manner.
The most common failure is that the cartridge heater cannot heat up normally after power-on. The main causes are divided into circuit problems and heater own damage. First, check whether the power supply voltage is normal, whether the wiring terminals are loose, fallen off or in poor contact, and whether the fuse and temperature control switch are blown or tripped. Loose wiring is the most frequent external cause; tighten the wiring terminals and check the circuit connectivity to solve such problems.
If the circuit is normal, the internal structure of the heater is damaged. The resistance wire may be broken due to long-term high-temperature oxidation, over-current impact or mechanical vibration. Use a multimeter to measure the resistance value of the heater; if the resistance value is infinite, it means the resistance wire is broken, and the heater needs to be replaced. In addition, moisture absorption of internal insulation magnesium oxide powder will lead to insulation breakdown, resulting in the heater not heating or leakage, which mostly occurs in humid working environments.
Local overheating and rapid burnout of the heater is another common failure, mainly caused by excessive power density and poor heat dissipation. When the selected heater power is too large, or the gap between the heater and the mounting hole is too large, resulting in poor heat conduction, the heat generated by the resistance wire cannot be conducted out in time, leading to local overheating and burnout of the resistance wire. In addition, blockage of the mounting hole, impurities on the heater surface, and failure of the temperature control system will also cause poor heat dissipation and overheating burnout.
The troubleshooting method is to check whether the heater power matches the equipment, clean the mounting hole and heater surface to ensure smooth heat conduction, replace the heater with appropriate power, and repair or replace the faulty temperature control system. For heaters with frequent overheating failures, it is recommended to customize products with reasonable power density according to working conditions to avoid recurrence of failures.
Electric leakage of the cartridge heater is a high-risk failure, mainly caused by insulation performance degradation and sealing failure. Long-term high-temperature operation leads to aging of internal insulation materials, or moisture and impurities enter the heater interior due to damaged end sealing, resulting in reduced insulation resistance and current leakage to the outer sheath. When electric leakage occurs, stop using the equipment immediately to avoid safety accidents.
Check whether the end sealing is damaged, replace the heater with damaged sealing, and dry the heater with moisture absorption of insulation materials (this method is only for temporary treatment, and it is recommended to replace the heater for long-term safe use). In humid and dusty environments, select heaters with enhanced sealing structure to prevent external impurities from entering and avoid leakage failures.
The heating efficiency of the heater gradually decreases during use, which is a recessive failure, mostly caused by oxidation of the resistance wire, carbon deposition on the sheath surface and loose internal filling. Long-term high-temperature operation leads to oxidation of the resistance wire, increased resistance and reduced heat generation; carbon deposits on the surface hinder heat conduction, resulting in lower overall heating efficiency.
The solution is to regularly clean the heater surface to remove carbon deposits and impurities, check the operating temperature, avoid long-term over-temperature operation to slow down the oxidation rate of the resistance wire. For heaters with obvious efficiency reduction, replace them in time to avoid affecting the production process due to insufficient heating.
In addition, mechanical damage to the heater is also a common failure cause. Forced knocking during installation, vibration and impact of equipment operation will cause cracks in the internal insulation layer, deformation of the resistance wire, and damage to the heater. During installation, standardized operation should be carried out to avoid forced deformation; for equipment with large vibration, add shock absorption measures at the heater installation position.
To reduce the occurrence of failures, daily preventive maintenance is crucial. Regularly check the wiring firmness, sealing integrity, surface cleanliness and heating uniformity of the heater, and conduct insulation performance testing regularly. For heaters reaching the service life, replace them in time instead of waiting for failures to occur, which can reduce unplanned equipment downtime.
When troubleshooting cartridge heater failures, follow the principle of first external circuit and then internal structure, first simple faults and then complex faults, which can quickly locate the problem. For enterprises with a large number of heating equipment, establishing a heater failure record and maintenance file can summarize failure rules, optimize selection and use plans, and reduce the failure rate of cartridge heaters.
