I am presently trying out a PRS1 without the heater tube. The supplier wants me to try it out before ordering another upgraded heater hose model as I was disatisfied with the Resmed S9 units mainly because of the inhalation sound and difficulty seeing how much water there was left.
In any event I really like the PRS1 unit. The water level is easily displayed and the respiration noise is muffled in comparison to the S9 unit. I presently have it set at Flex 3 which works well for me but was wondering what the difference is between the humidifier setting of Classic ©, and System One (O) ? The other setting is for heater hose which this machine does not have. I presently have it set for (O) and a level of 3 and it doesn't seem to be using much water. Perhaps 1/2 an inch per evening and the heater plate doesn't seem to be warm to the touch when I slide out the water tray. Is this normal?