AirSense 10 says mask is leaking but it's not

When I started CPAP over three years ago, I had no problems except mask leakage. I bought five different masks until I found one that did not leak--the F&P Simplus Full Face Mask. The problem is that my AirSense 10 consistently records leakage between 60 L/min and 120 L/min each night. I'm convinced that there is no leakage other than the exhaust. How do I know this? Because my second-besk mask, a Philips Respironics Comfort Gel Blue full face, leaks occasionally and both the sound and sensation eventually wake me up. To know for sure, I put the Simplus mask on and watched a long movie. After three hours of leak-free CPAP (from mask, tube or machine), the machine showed a frowny face for leakage.

The AirSense 10's leak scores are supposed to compensate for exhaust loss, and the Simplus mask says the loss is 60 L/min at a pressure of 25, which happens to be my maximum pressure setting. My AHI (events per hour) is generally around .6, which is not terrible, but does not correlate with the L/min from night to night. For those familiar with the AirSense nightly scoring system, this means that my scores always hover right around 80% but never higher.

I've read dozens of threads regarding leaks and AHI, but have never come across someone who is convinced there is no leakage despite the recorded data. Has anyone else had this issue?

As a shot in the dark, is there any possibility of a leak in the humidifier to unit seals? or in the hose or connections somewhere? I once had weird issues with my A10 when the humidifier reservoir was not fully pushed in.

That aside where are you getting the leak rate from? If you set the Essentials option to Plus in the Clinical Menu you can get an expanded sleep report in the user menu. It reports average leak rate over the night, or average over a number of nights.

The best way to track mask leaks is by using SleepyHead. It reports a % of time over the leak redline. It also displays the leak redline and graphs the real time leakage over the night. It would be interesting to see if it displays the same as what you are currently getting. From MyAir? Here is an example of the leak rate graph in sleepyhead for a bad night...

And, a good night:

SleepyHead would give you more information on when the leak is happening. This all said, if there really is no leak anywhere, you may have a defective machine. I take it your mask type is set to full face? If it is set to nasal pillow, it might be over reporting the leak as a full face uses a much larger purge flow than a nasal pillow.

Crazy...I came here to ask about a nearly identical problem (although mine is an Aircurve 10 Vauto). I've used the same mask since I started nearly a year ago and have always had good seal until recently. Bought a replacement mask...no luck. New hose...no luck. Tried sleeping on back (normally a side sleeper)...no luck. Mask is tightened down to the point of being painful.

When I went to bed last night I could not get the SmartStart feature to auto start the machine. I finally pushed in on the water reservoir and then it started. Suspect there was a significant leak between the machine and water reservoir. I think my seals are OK though. If you look at pages 24 to 27 in the manual at the link below it shows you how to take the machine apart to inspect the seals.

A10 Technical Manual