Siemens Temperature sensor QAA32

This is a temperature sensor based on an NTC sensing element. It measures air temperature and transmits the reading to Siemens controllers and automation. The device offers high measurement accuracy and stable data transmission. Its compact modern housing and robust construction make it suitable for installation in typical building services applications.

When choosing a replacement for this kind of sensor, confirm that the resistance–temperature characteristic matches the control board; common values are 10 kOhm or 12 kOhm at 25 °C. Also verify the physical mounting form—immersion, clamp-on, or sleeve—and check the cable length and connector type. It is prudent to measure the existing sensor’s resistance at a known temperature before ordering a replacement.

Failures of NTC sensors of this type usually show as a drifting resistance curve, a broken cable, or poor thermal contact when the probe is clamp-on mounted. The controller may then modulate incorrectly or report an implausible temperature. Check the sensor with a multimeter at a known temperature and inspect the mounting and wiring.