What Are The Various Reasons That Cause A Thermocouple To Fail?

A thermocouple is an electronic device that is required to measure high temperatures especially in the industrial processes and settings. It consists of two wires of different metals that are joined at one end. The other end of the wires is connected to a measuring instrument. The instrument measures the voltage that is generated when the two metals are at different temperatures. There are many environmental and operational factors that can cause a thermocouple to fail beyond a certain time affecting the accuracy of any temperature measurements. So, it becomes extremely important to understand the thermocouple failure modes that can affect the accuracy of a thermocouple in temperature measurements over time, and a thermocouple will subsequently fail to generate accurate measurements. 

Thermocouple Failure Modes That Can Cause A Thermocouple To Fail!

  • Corrosion Due to Oxidation Overtime: One of the most common causes for a thermocouple to fail is due to corrosion. The wires can become corroded if they are exposed to moisture or chemicals. This can cause the wires to break or the connection to the measuring instrument to become loose.
  • Physical Damage: Another reason for a thermocouple to fail is due to physical damage. The wires can become damaged if they are bent or stretched. This can cause the wires to break or wired connections become loose. The physical damage can also be caused if the thermocouple is used in conditions where the temperature levels exceed the temperatures that the device is actually calibrated for. The excessive heat will lead to physical damage to the thermocouple. 
  • Metal Fatigue: Due to continuous exposure to high temperatures, the metals will start showing characteristics of metal fatigue as the metals do expand and contract regularly because of any change in temperature. Such fatigue will lead to weakening of the thermocouple to generate most accurate readings over time. 
  • Welding Issues: During preparation of the metal for the thermocouple, improper welding may lead into open connection which can cause the thermocouple device to fail. As this issue can be easily detected, it should be fixed immediately with the help of an expert, and one should be careful to check the weld while installing a thermocouple. 
  • Using A Wrong Thermocouple: Different thermocouples have obviously different types of characteristics. Based on the type of a thermocouple, it needs appropriate matching type of electronics being used in order to decode signals received from the thermocouple. So, it is important to check the thermocouple parameters from an expert technician.
  • Improper or Inadequate Insulation: If the thermocouple wires are not properly insulated, they can also become damaged. This can cause the wires to become loose or loosening of the connection to the measuring instrument itself, which may result in inaccurate temperature readings. 
  • Calibration Issues: If the measuring instrument is not properly calibrated, the readings can be inaccurate. In such a situation, the thermocouple is required to be replaced. You might need an expert to evaluate the thermocouple device periodically in order to check and verify the calibration in order to fix any such issues. 
  • Poor Installation: Thermocouples can also fail due to poor installation. If the wires are not properly connected or the operating conditions are not compatible with the thermocouple device, it will ultimately lead into failure of the thermocouple device.

Heatcon – A Leading Manufacturer & Distributor of High-Quality Thermocouples!

If you suspect that your thermocouple has failed or is not giving the most accurate readings, you should contact the expert team of engineers at Heatcon to get the best advice for any repairs that are needed, maintenance, or complete replacement of your thermocouple device. It may be any of the above-listed thermocouple failure modes that your thermocouple device has failed, it is always important to have it checked by a qualified technician only.