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).

jsmit86 wrote: ↑

Tue Jun 10, 2025 1:28 pm

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

It does behave correctly if I don’t run out of water. I have the humidifier set to four and I occasionally have an air leak with my mask. Most mornings I wake up dry. If I set it above four then water makes a gurgling noise in the tube.

D.H. wrote: ↑

Mon Jun 23, 2025 9:09 pm

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).

This is the first machine that has put out an odor of any kind.

msla wrote: ↑

Fri Jun 20, 2025 11:36 am

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.

This emptying of the reservoir occurs approximately every two to three months. I have it set to auto everything but won't last eight hours, if I cold sleep that long. No crust on the plate, perhaps a burnt dry powder smell. It’s not any smell I have come across in my life. It’s fairly strong.

jsmit86 wrote: ↑

Tue Jun 10, 2025 1:28 pm

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

It works fine if I don’t run out of water. This doesn’t happen very often. When it does it's scary because the is a strong odor.

msla wrote: ↑

Fri Jun 20, 2025 11:36 am

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.

Sorry...belated response to your question.

My settings"

Manual
Tube Temp 18 c
Humidity 2

Fixed my dry reservoir immediately and permanently.

I would run out of water if my humidifier was set to 4 or above and I would get a burning smell and the bottom of the humidifier was scorched. Now in the winter it is never past a 3 and runs low and always need filled. with summer and high humidity I have it at one. Hardy uses any water then. To keep my nose moist I use Flonase and Ayr be just before I go to bed and blow my nose good. I have Asthma and Chronic Bronchitis.Always have a cough and wheeze. This heat and humidity in MI is killing me.