The RF heads should gradually feel warm during use. The Vacuum RF head may also warm when the RF function is active. The 80K cavitation head can generate some warmth, but it may feel less noticeable than the RF heads. Please make sure the timer and energy level are set above 0 and use enough conductive gel. If the RF heads remain completely cold after several minutes of use at a moderate setting, please stop using the machine and contact **[service@freyara.com](mailto:service@freyara.com)** with your order number and a short video so we can check it for you.