the "/U" suffix simply denotes a "Unitary" or retail-packaged version

750mV at 650°C

most 46K13 assemblies include the necessary hardware to secure the 1/2" hub to the motor shaft

yet compatible with R-404A

It is functionally identical to the 140S-3-3/4-150 and LF140S3-150-3/4 models

Trane SEN1809 Temp Sensor 319848-301 the "/U" suffix simply denotesWhen you're troubleshooting a lockout or erratic discharge air temperature on a Trane or American Standard unit, a failing thermistor is often the culprit. The Trane SEN1809 is a genuine OEM thermistor temperature sensor designed specifically for a 3 4" tube mount. This NTC (Negative Temperature Coefficient) sensor provides high accuracy resistance feedback to the control board, ensuring the system maintains precise setpoints and avoids coil freeze