I wonder if somebody could help me identify where I am wrong:

I have an analogue temperature sensor in my hand and cannot find out what kind of sensor this is.

  • It is a two wire crimped cylinder (diameter 6mm), used for domestic heating applications. It is equipped with a silicon cable.
  • I first thought it would be a standard PT 1000 but a resistance measurement yielded a value of about 1.8KΩ when I warmed the sensor with my hand.
  • The sensor has a positive resistance curve as the resistance was slowly rising when the sensor got warmer.
  • The resistance was measured with ambient temperatures around 10°C.
  • The sensor is an unused spare part, lying around for about 5 years and a visual inspection yields no abnormalities.

So that causes me doubts:

  • I cannot find some standard, positive curved, temperature sensors with that values.
  • I doubt that the heater manufacturer used some tailor-made temperature sensors when there are cheap, established sensors around (like a PT 1000)
  • An measurement error seems unlikely as the difference to an established sensor type is way too much. Even an sub-par multimeter should not have that error-range.

Does somebody know a standard sensor with matching characteristics?

  • \$\begingroup\$ Do you still have the heater it is for, or know what heater it is for? The documentation (installation and service manual) for that might tell you. \$\endgroup\$ Commented Mar 5, 2018 at 10:04
  • \$\begingroup\$ You mention it was laying around for 5 years... Is it possible that it is simply defective (and that was why it was laying around in the first place?) \$\endgroup\$
    – Joren Vaes
    Commented Mar 5, 2018 at 10:19
  • \$\begingroup\$ Any resistive sensor would have a positive coefficient. The best ones use platinum. \$\endgroup\$
    – Finbarr
    Commented Mar 5, 2018 at 10:21
  • \$\begingroup\$ @JorenVaes Could be, albeit I have no information about that \$\endgroup\$
    – Martin
    Commented Mar 5, 2018 at 10:22
  • \$\begingroup\$ Have you considered that throwing the device in the trash is ultimately more cost effective for you and for the people's time on this site being wasted reading this. Anything lying around for 5 years cannot be relied upon. Bin it and move on. \$\endgroup\$
    – Andy aka
    Commented Mar 5, 2018 at 12:01

1 Answer 1


There are a plethora of crappy cheap base-metal RTDs used in comfort heating applications. Typically nickel or nickel-iron alloy.

There are a number of 'standards', including ~2K at about room temperature.


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