Liebert FP4022 Fan Safety Switch

Liebert FP4022 is a Tri-Delta fan safety switch (model/part number FP4022) used in HVAC and cooling systems to monitor fan operation and provide safety interlock based on airflow or pressure conditions. Commonly installed in Liebert precision cooling units, air handlers, and commercial HVAC equipment requiring fan status monitoring, it verifies fan operation to protect equipment from airflow-related issues. HVAC technicians and maintenance teams use this switch for equipment repairs, preventative maintenance, replacement of failed safety switches, and restoring proper fan protection operation. This 120–277 VAC, 60 Hz device carries a 15 A rating and provides 1 normally open and 1 normally closed contact. The set point is approximately 0.17 ± 0.05 in. W.C., and it uses spade terminals for connection, mounting on an HVAC equipment panel or air handling assembly. Applications include Liebert cooling systems, air handlers, ventilation systems, and other commercial/industrial HVAC installations requiring fan monitoring and safety interlock to protect equipment.