ActronAir Suction Temperature Sensor NTC030WF00 "Hercules" (Carel) monitors refrigerant suction temperature at the compressor inlet on Hercules commercial systems, providing the suction superheat data the CM100 board uses to protect the compressor from liquid refrigerant slugging and to optimise capacity in variable-load commercial applications. The NTC030WF00 is a Carel wet-contact sensor specifically rated for direct refrigerant contact -- substituting an air-temperature NTC sensor in this position risks compressor damage from undetected liquid refrigerant events. Isolate power and recover refrigerant before replacing any Hercules refrigeration circuit sensors.