When the tube it lit you can change to any frequency you want throughout the session without having to stop and restart the device. You may have to fine tune the tuner from time to time. Each device is slightly different in operational charactoristics. Our RifeBare devices are bench tested to run for 2 hours - non stop. We have experienced machines overheating after delivery is taken - so we make this 30 minute operational period precautionary.
Most units can run all day long without any problems.
Rough handling of the boxes during courier transport probably has caused some adjustment or component to move which leads to an overheating problem. As a precaution we say this. Most units can run from 30 seconds to all day long without the tube being lit. So a little Helium and other gasses wererecommended to help with tube ignition. The more Photons - the better effect.