Problem with Airsense 11.

I have been a C-Pap user for approximately 10 years. For most of those years I used the Resmed Airsense 10.No problems at all. I’ve had a newer Resmed Airsense 11 AutoSet for about 16 months now. It has a problem but the company denies this. It’s been sent back twice and they say nothing is wrong. The local provider of course backs the company. I’m checking to see if anyone else has had this problem. If the water reservoir becomes empty, which is rarely, a bad smell comes through the machine into my mask. It’s bad enough to wake me up, usually right a way. . if I don’t wake up quick enough I can taste it and has even has gotten into my throat. It has been sent back twice as I mentioned and they think I’m crazy. Has anyone else ever had this problem? I bought a mini and don’t know if I ever want to go back to my Airsense 11.

Does everything work normally if you don't run out of water?
Is there a specific issue that makes you run out of water?

Nothing is wrong, you are describing a behavior that many have complained about for the Air 11, Air10, S9 and even non-ResMed devices.

Heating plastic smells. Without any water in the tank, you are going to get that smell.

When your machine is dried out...do you observe any white calcification on the plate in the reservoir?

Before I dialed in my temp and humidity settings,... I used to frequently empty the reservoir in a single night and the plate used to develop a slight crust ( which I cleaned)
This used to give me a taste and smell sensation. Not plastic...more like a burnt dry powder.

Craig H wrote: ↑

Wed Jun 11, 2025 10:23 pm

When your machine is dried out...do you observe any white calcification on the plate in the reservoir?

Before I dialed in my temp and humidity settings,... I used to frequently empty the reservoir in a single night and the plate used to develop a slight crust ( which I cleaned)
This used to give me a taste and smell sensation. Not plastic...more like a burnt dry powder.

What settings did you use to deal with the empty reservoir? Mine went there last night: 8.5 hours used, Tube 70, and humidity auto.

You folks who have had the water chamber go dry on you.....
What pressures are you using and what is your leak rate?
What is your ambient humidity in your bedroom?

I could (and did) use the AirSense 11 AutoSet for a period of time and at a setting of 8 for humidity I didn't run out of water with 9 hours of use.
But then my leaks are minimal and my pressures were running around 10 cm on average.

To some extent, I've been aware of a bad smell when the water runs dry in every CPAP I've ever had. I'm on #6 now, which is an Airsense 11. I don't find the odor any worse than any other machine I've ever owned (including the recalled one).