The pump motor used in the Perifit Pump may generate some heat, and it is normal for the hub to feel warm to the touch as this heat dissipates from the motor. You may notice this especially at the end of a longer pumping session.
However, the hub should never get hot. If your hub feels hot to the touch or the charger gets deformed or melts while charging, turn the breast pump off, unplug it immediately, and contact our customer support.