No, it doesn't have fan on demand. It's likely you are used to running units with comparatively lower duty cycles. The fan runs continuously to provide the duty cycle of 60% at full amperage. For people that have been around welders for a while having a continuous running fan is nothing new. I've got an ESAB MIGmaster 250. If the switch is on, the fan is howling. It's got 50% duty cycle at 250 amps...on 240V 1 phase.