Possible manufacturing defect ResMed AirSense 10?

Have you reset the clock on the machine to the correct time only to find that when you go check it later the time change didn't stick?

Interesting problem, LJT. As you're finding out, ResMed products are fussy about the time, but at least it can be set unlike some others. Mainly the machines don't like being set back in a period which already has a sleep session, which makes it tough for you since your sleep sessions span two ResMed "days" which start at noon. Generally, advancing the time is not a problem.
As far as the machine changing times, I don't know, I don't have an Airsense, but if you've changed the time in the clinician's menu and then gone back to the clinician's menu (not the computer) and the time has changed from what you entered, then I suppose it's possible that time corrections are being made by the wireless monitoring system of the AirSense. Is your DME in another time zone, by chance? I think this is really far out, but these days, anything is possible.
As far as setting the machine ahead 4 hours, I would consider setting it ahead 12 hours (changing noon to midnight) so that the machine thinks it is nighttime when you are sleeping and the next day (night) when you are awake it will change "days". That way, your sleep sessions would be in the same ResMed "day" and your stats would make more sense. If that makes sense
Maybe others can see a problem with this solution, but I think it would work if you're to be on the same schedule for a while.

Thank you again Den

If you were to set your ResMed time ahead 12 hours, I think you would want to do it in the afternoon after your 2nd sleep session...maybe. Changed my mind, see edit 2 below.

edited to add: And if and when you were to set the machine back to the correct time, the machine stored compliance data might have to be erased.

Airsense10 manual wrote:Set the current date.
If you set a new date that occurs in the past then an error message is
displayed. Before this change can be made, erase the compliance data
available under the Configuration menu.

Edit 2: In thinking about this a little more, I think the best way to advance 12 hours would be after your first sleep before noon. This way, you could advance the time without going into the next calendar day.

This is what I did to overcome the time zone problem:
1. download and process your SD card using Sleepyhead or Resmed software
2. then format the SD card on a PC
3. slip in the SD card back to 10
4. change the time
since there is no data in the Sd card, there will be no resistance from the Airsense 10 to the time change

cpapernewbie wrote:This is what I did to overcome the time zone problem:
1. download and process your SD card using Sleepyhead or Resmed software
2. then format the SD card on a PC
3. slip in the SD card back to 10
4. change the time
since there is no data in the Sd card, there will be no resistance from the Airsense 10 to the time change

Formatting the SD card does nothing for this problem. The machine doesn't care about the data on the SD card. It stores some of the data internal to the machine. If you have a "time travel" problem, you have to erase the data stored inside the machine itself.

Basically, you can only set the machine back in time to the last time you turned the machine off. Assume your machine thinks it's noon. Turn it off and wait 8 hours and it will think it's 8 PM. At that point, you can set the machine's clock back to noon, but no earlier, without erasing any data. It won't let you overwrite any old data.

At least that's the way it works for S9. I haven't gotten my hands on an A10 model yet.

I don't think the Airsense 10 changes time zones based on the cellular network. I had mine setup at a DME located in Eastern Time.. I traveled with the machine almost immediately, I've been in Central Time for the past 10 days but the machine still shows Eastern Time. I know the cellular connection is still working because my DME has called twice so far while traveling to report that everything looks good on their end with regard to compliance, AHI, leaks.