Pressure Fluctuations

I noticed some interesting pressure fluctuations in my S9 Escape. I took my old GoodKnight 420G and the new S9 Escape to my doctor. We hooked the S9 up to his magnehelic gauge and saw that the pressure fluctuated like crazy when I breathed or there was a leak. With the pressure set to 17, it would actually vary from about 14 to 22 during normal breathing. Also, a small to medium leak would cause the pressure to increase to as high as 24 as the machine overcompensated. The GoodKnight, on the other hand, kept a very steady pressure. Has anyone else seen this?

I've since traded my S9 Escape for an Elite. I don't have a manometer to check it myself, but the data on the card claims that the pressure stays between 16 and 17 nearly all the time. Is this data reliable? Would the Elite really behave that much differently than the Escape?

I should add that both of my S9 machines had the EPR feature turned off.

If you have access to a decent pressure gauge, I'd like you to please try an experiment. See if your pressure varies depending on breathing and/or leaking. Then report back with the following information:

• machine make and model
• pressure setting
• high/low pressure measurements during normal breathing
• Is there an increase in pressure when there's a leak? If so, how high can you make it go?

For extra credit, try to answer this question. During a leak, is there a measureable pressure difference between each end of the hose?

Thank you!