Common faults and troubleshooting of far-infrared ceramic heaters

I. Initial Evaluation of Heater Authenticity

1. Structure:

Our products are overmolded. The heater body and mounting slot should be clearly distinguished by color.

2. Logo

The front should include the "Product Model" and other parameters, such as power, voltage, and maximum operating temperature. The back should also include the CE mark.

II. Heater Application Principle

Infrared radiation, λ = (2-10) μm, is well absorbed by most objects within this wavelength range.

The heater's T increases, and λ decreases, indicating greater penetration.

According to Wayne's Law, the closer the distance, the higher the radiation intensity (60%-70% of the radiation intensity at d = 70 mm. Adjust the distance appropriately based on production requirements).

III. Regarding Heater Materials

1. Regarding the Heating Wire

Material: Kanthal AF: Aluminum-chromium-iron.

Resistance can be calculated using Ohm's Law: R = U²/P.

Power P increases, resistance R decreases, and heating wire diameter L increases.

2. Regarding Thermocouples

K Type;

Material: Nickel-chromium (+) - Nickel-silicon (-);

Resistance: 0.3-5Ω;

K-type thermocouples have an error of ±0.4%t when measuring temperature, Class I;

Maximum temperature: 1000°C, temporarily up to 1200°C;

3. About the Ceramic Body

Special Formula

4. About the Insulation Cotton

THI: Aluminum Silicate

5. About the Internal Wire

The operating temperature range of the heater's internal thermocouple wire is -200°C to 1200°C.

6. About the External Wire

① Nickel Conductor: Stranded wire, 2.5mm², 11A, nickel, 500°C max.

② Thermocouple Wire: Solid wire, nickel, 400°C max.

③ Compensating Wire: Stranded wire, 1.5mm², 100°C max.

IV. Regarding Heater Installation

Mounting Hole: 15×40, Mounting Plate Thickness ≤ 1.5mm

V. Heater Quality Inspection

1. Heater Quality Inspection without Thermocouple

① Calculate the resistance value using Ohm's law: R = U² / P. If the measured value is within a ±6% range from the theoretical value, this is normal. The resistance value will vary at different temperatures. If it is outside this range, please contact our sales representative for a replacement.

2. Heater Quality Inspection with Thermocouple (Type K)

① Follow the same quality inspection method as for heaters without thermocouples: inspect the heating wire.

② If no problems are found in step 1, continuously test the thermocouple resistance on the heater. The resistance should be between 0.3 and 1Ω.

③ After proper wiring, apply power continuously for 20 minutes and measure the thermoelectromotive force across the thermocouple. If the thermoelectromotive force continues to rise, the thermocouple is considered to be faulty.

(If there are any quality issues, please contact our sales representative for a replacement.)

VI. Precautions Before Use

1. Thermocouple Type Matching

The thermocouple type on the temperature controller should match the type of the built-in thermocouple in the heater.

2. Correct Wiring

The end of the thermocouple wire with the dark green marking is the positive terminal and should be connected to the positive terminal on the temperature controller.

3. Temperature Controller Auto-Tuning

Before use, set the temperature controller to the normal operating value for the system and power on for auto-tuning.

VII. Temperature Display Issues

1. "Temperature Drift"

Problem Description: When the displayed actual temperature reaches near the maximum setpoint, the actual operating temperature value fluctuates significantly (the allowable fluctuation varies depending on the system), potentially by tens of degrees Celsius.

Cause: Temperature controller setup issue

Troubleshooting:

① When using a temperature controller and thermocouple for the first time, auto-tuning the temperature controller is required to adjust the temperature controller parameters to match the thermocouple's performance. Please refer to the operating manual of the corresponding temperature controller for details.

② If the problem persists after following solution 1, power the heater continuously for 20 minutes and test the thermoelectric voltage across the thermocouple. If the voltage continues to rise, the thermocouple heater is considered faulty. Replace the thermocouple wires and temperature controller to determine the cause. If the voltage does not continue to rise, contact our sales representative to have the heater replaced.

2. The temperature continues to drop (an abnormal alarm appears after reaching a certain temperature).

Problem Description: The temperature reading on the temperature controller continues to drop.

Cause: Wiring is reversed.

Troubleshooting:

① Check the thermocouple and compensation wire connections for correct connection.

The end of the built-in thermocouple wire with the dark green marking is the positive terminal. Connect the positive terminal of the thermocouple wire (our thermocouple wire's positive terminal is green). Connect the positive terminal of the compensation wire (our compensation wire's positive terminal is green). Connect the positive terminal of the temperature controller.

② If solution 1 checks correctly and the fault cannot be corrected, please check the heater quality according to the previous step (5) - Heater Quality Inspection. If the heater is not the problem, replace the temperature controller to determine if it is a quality issue. If the heater is the problem, please contact our sales representative for a replacement as soon as possible.

3. The temperature rises to a certain value and then begins to drop.

Problem Description: The temperature rises when power is turned on, but begins to drop before reaching the set temperature.

Problem Category: Thermocouple wire quality issue

Troubleshooting Solution:

① Replace the thermocouple wire to check for quality issues. If the problem is with the thermocouple wire, replace the thermocouple wire to troubleshoot.

② If the problem is not with the thermocouple wire, check the heater quality as described in Section 5 - Heater Quality Inspection. If the problem is with the heater, contact our sales representative for a replacement. If the problem is not with the heater, replace the temperature controller to determine the cause.

4. Thermocouple Type Setting Error

Problem Description: Abnormal temperature control

Problem Category: Temperature controller setting issue

Troubleshooting Solution:

① Check the temperature controller settings and the thermocouple type. After setting correctly, auto-tune the temperature controller.

② If the problem persists, check the heater for quality issues.

5. Several heaters are being used simultaneously, but only some are experiencing temperature display issues.

Problem Description: Several heaters are being used simultaneously, but only a few are experiencing malfunction.

Troubleshooting:

① Check that the positive and negative terminals of the thermocouple are correctly wired (the dark green marked terminal is the positive terminal).

② If the wiring is correct, measure the resistance of the heating wire and the thermocouple. The resistance of the heating wire can be calculated using R=U²/P. The resistance of the thermocouple should be between 0.3 and 1Ω. If both resistances are normal, power the heater for 20 minutes and measure the thermoelectromotive force (TEF) across the thermocouple. If the TEF continues to rise, the thermocouple heater is considered faulty. If the problem is a quality issue, please contact our sales representative for a replacement heater.

③ If no quality issues are identified in solution ②, but the heater still malfunctions, replace a working heater with one to see if it works properly. If the device still doesn't work properly, please check the wiring. If it works properly, please contact our sales representative and return the product for testing by our professionals.

6. Issues Due to Sleeve Material Problems

Problem Description: After replacing the terminal block, the wire sleeve frequently burns out during use.

Cause: Incorrect sleeve material selection.

Troubleshooting: The wiring space on the back of the heater is relatively hot during use. If copper or other materials that are not heat-resistant are used, this problem may occur. The correct solution is to use nickel alloy or stainless steel wire sleeves.