Re: NTC thermistor failures

On Wed, 9 Jul 2025 23:20:43 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:

I'm looking to purchase some thermistor-based probes to
monitor the performance of the HVAC system (return and
supply duct temperatures along with liquid and suction
lines.  Maybe the temperature of the compressor, etc.)
>
As part of my research, I look at the problems people
(consumers) report with the units used in their systems.
>
I would have thought NONE of these would fail:  they are
out of the way so not likely to be physically disturbed;
often encased in a protective sheath (e.g., probes);
shouldn't be operating beyond their design constraints
(unless poorly designed); etc.
>
Even the pigtails from such devices should be reasonably
safe from disturbance!
>
Yet, I see folks replacing them and proud that they
did so without calling in the HVAC contractor!
>
Are there other "wear" factors that come into play?
What sort of service life (in a conservative design)
should I expect?

Thermistors should last forever.

Probably bad solder joints inside. Cheap junk from you-know-where.