The troubleshooting of the ceramic heater not heating up should follow the logical chain from the power supply to the load. Combined with the resistance characteristics and temperature control mechanism of the ceramic heater, the root cause of the problem should be gradually located. The following are the systematic troubleshooting steps and key analyses:
First, check the power supply and circuit
Abnormal power supply
Voltage loss: Use a multimeter to measure the input voltage (such as 220V or 12V). If the voltage is 0, check whether the power plug, fuse, and circuit breaker have blown. For instance, a user found that the heater was not responding. After measuring, it was found that there was no voltage in the power socket. After replacing the fuse, the power supply was restored.
Insufficient voltage: If the voltage is lower than the rated value (for example, the nominal voltage is 220V but the actual measurement is 180V), it may result in insufficient heating power or even failure to start. It is commonly seen when old circuits or high-power devices are connected in parallel.
Polarity error: If the positive and negative poles of a DC power supply device (such as a vehicle-mounted heater) are reversed, it may trigger the protection circuit or damage components.
Line fault
Open circuit in the wire: Check whether the power cord and the heater lead wire are damaged or broken. For instance, the lead of a certain heater was bitten through by a pet. After being re-welded, it regained heat.
Poor contact: Oxidation or loosening of plugs and terminal blocks can lead to increased resistance. You can use sandpaper to remove the oxide layer and tighten the screws.
Overload protection: If a leakage protection device or overcurrent relay is installed in the circuit, it is necessary to check whether the tripping is triggered by leakage or excessive current.
Second, malfunction of the ceramic heating element
Abnormal resistance
Open circuit: Use a multimeter to measure the resistance at both ends of the heating element. If it shows ‘∞’ or far exceeds the nominal value (for example, the nominal value is 10Ω but the actual measurement is greater than 1 MΩ), it indicates that the ceramic body is internally broken or the electrode has fallen off. It is commonly seen in high-temperature aging or mechanical shock.
Short circuit: If the resistance approaches 0Ω, it may be due to the breakdown of the ceramic insulation layer or a short circuit of the electrode. For instance, a certain MCH heater suffered from the breakdown of the Al₂O₃ insulation layer due to moisture, and the heating element needs to be replaced.
PTC characteristic failure: If the Curie temperature of PTC ceramics drifts or their resistivity decreases, they may lose their self-limiting temperature function. For instance, after a certain PTC heater has been in operation for a long time, the Curie temperature drops from 120℃ to 80℃, resulting in insufficient heating.
Physical damage
Cracks or breakage: After a ceramic body is impacted by an external force and develops cracks, it may experience local overheating or open circuits due to thermal stress concentration.
Electrode detachment: When the bonding force between the metal electrode and the ceramic substrate is insufficient, it may peel off at high temperatures. For example, the silver electrode of a certain flexible ceramic heating film fell off due to repeated bending.
Third, malfunction of the temperature control system
Sensor failure
Open circuit/short circuit: An open circuit in a thermocouple or NTC thermistor can cause the temperature controller to misjudge the temperature, such as an abnormal NTC resistance value (it should be 10 kΩ at room temperature but is measured to be greater than 1 MΩ).
Accuracy drift: After long-term use, sensors may experience zero drift. For instance, the measured value of a certain PT100 platinum resistance may deviate by ±5℃ at 100℃, resulting in inaccurate temperature control.
Improper installation position: If the sensor is not in close contact with the surface of the heating element, the heater may start and stop repeatedly due to temperature measurement lag.
Controller failure
Relay adhesion: Contact adhesion of solid-state relays or mechanical relays can cause the heater to remain powered on continuously or fail to connect. For instance, the relay contacts of a certain temperature controller oxidize, and the contact resistance increases to 10Ω, resulting in a decrease in heating power.
Program error: If the parameters of the programmable temperature controller are set incorrectly (such as setting the target temperature to 0℃), it will cause the heater not to work.
Electromagnetic interference: A strong electromagnetic environment may cause the controller to malfunction. It is necessary to check the shielding measures (such as installing a metal casing or filter).
Fourth, environmental and usage factors
Deterioration of heat dissipation conditions
Dust accumulation or blockage: When the heat dissipation holes of the heater are blocked by dust or foreign objects, it may cause the thermal protector to act. For instance, a certain warm air blower triggered overheat protection when the internal temperature rose to 150℃ due to a blocked air inlet.
The ambient temperature is too low: At extremely low temperatures, the resistivity of PTC ceramics may increase abnormally. Therefore, low-temperature PTC materials (such as strontium-doped BaTiO₃ -based ceramics) should be selected.
Excessive air humidity: A humid environment may cause leakage of electricity in the ceramic body or short circuits in the sensor. It is necessary to enhance the waterproof design (such as applying conformal coating).
Load mismatch
Power overload: If the rated power of the heater is 500W but the actual load is 800W, it may cause the fuse to blow or the heating element to burn out.
Voltage fluctuation: When the voltage fluctuation of the power grid exceeds ±10%, it may affect the heating efficiency. For example, the voltage dropped from 220V to 198V, and the heating power decreased to 81% of the nominal value.
Fifth, suggestions for the investigation process
Preliminary inspection
Confirm that the power supply is normal → Check the circuit connection → Observe the status of the indicator light/display screen.
For example, if the indicator light of a certain heater is not on, first check the power supply and fuse.
Step-by-step testing
Direct power supply test: Disconnect the temperature control system and directly short-circuit the heater lead. If it gets hot, the temperature control system is faulty; otherwise, the heating element is faulty.
Resistance measurement: Measure the resistance of the heating element in a cold state and compare it with the nominal value; Measure whether the resistance change in the hot state conforms to the characteristics of PTC.
Sensor verification: Test the temperature-resistance curve of the sensor using a constant temperature box or ice-water mixture to confirm whether it deviates from the standard value.
Replacement verification
Replace the known well-functioning heating element, sensor or controller to quickly locate the faulty module. For instance, if a certain heater resumes heating after replacing the PTC ceramic, it indicates that the original heating element has failed.
Sixth, Analysis of Typical cases
Case 1: A certain electric heater does not heat up. The measured power supply voltage is normal, but the resistance of the heating element is ∞. Disassembly revealed internal fractures in the ceramic body. After replacement, it was restored.
Case 2: The hot bed of a certain 3D printer does not heat up. The resistance of the heating element is measured to be normal, but there is no voltage at the output terminal of the temperature controller. Upon inspection, it was found that the relay contacts were oxidized. After replacing the relay, everything was normal.
Case 3: A certain industrial oven heats up slowly. Monitoring reveals that the actual voltage is only 180V. After upgrading the power cord diameter, the heating speed has increased by 30%.
Summary
The troubleshooting of a ceramic heater not heating up should follow the sequence of ‘power supply – circuit – heating element – temperature control – environment’, and quickly locate the problem by combining methods such as resistance measurement and replacement verification. The key points include:
Give priority to troubleshooting the power supply and lines (accounting for approximately 40% of faults);
Focus on the resistance of the ceramic body and the characteristics of PTC (accounting for approximately 30% of the faults);
The faults of the temperature control system and sensors need to be tested in combination with parameters (accounting for approximately 20% of the faults).
Environmental factors and load matching cannot be ignored (accounting for approximately 10% of faults).
Through systematic troubleshooting, the heating faults of ceramic heaters can be efficiently resolved.
We are professional electric heater manufacturer, we are specialized on producing all kinds of electric heating element, such as ceramic band heater, mica band heater, sus cover, air blower fan and casting aluminum band heater.
We have this advantages
Price:We have a effective method on controlling products′ cost, so the price is the best Quality: We have many years of working experience on quality control, so we can ensure the quality.Official website address:http://www.fswen.com/
