When replacing a Fasco D653

Durable OEM Construction: Corrosion-resistant material prevents the pitting and cracking common in aftermarket A/C drip pans

This allows the technician to tune the proportional response of the controller relative to the sensor input deviation from the setpoint

Y compressor signals

Always cross-reference the original part number or measure the 3/4" bore and wheel dimensions before ordering

Siemens DDC 540-378 AutoZero Module 323080-701 When replacing a Fasco D653The Siemens DDC 540 378 AutoZero Module is a high precision calibration component engineered for Siemens building automation systems. This module serves as the primary solution for mitigating sensor signal drift within analog input loops, ensuring that pressure and airflow transducers maintain a stable baseline. By automating the zero point adjustment, the 540 378 eliminates the need for frequent manual recalibration in VAV systems and air handling