The transducers are heat sink to the tank and they will overheat if the tank is low or dry. On my 10L a 30m cycle can raise the water temp as much 10C and that is with a full tank. ANd maybe reasons the manufacture says not run the unit without enough liquid in tank. Just don't try that as I have already fried one unit by forgetting to turn the heater off before draining.
I only cleaned one 42CC chainsaw cylinder so I don't a real history cleaning these larger items. It did clean it well but it wasn't too dirty either.
I haven't notice any differences myself if sweep works or not. Both units seems to take just as long to clean. The on mine goes from 38-42 KHz.
Degas is simply the removal of excess air from the cleaning fluid. You can do the same by doing a quick 1-2 min cycle in regular model.
