ResMed AirSense 11 AutoSet
Find the message on your screen below. Most alerts clear with a simple check: the water chamber seated, the tube connected, the filter clean. If a code keeps coming back after the fix, stop using the machine and contact your equipment supplier or the manufacturer.
What it means: The humidifier tub or side cover is not seated properly, so air escapes at the machine.
What to do: Pull the tub or side cover out and push it back in until it is correctly inserted, then restart therapy.
What it means: The tubing is loose at one end, or the mask is fitted incorrectly.
What to do: Push the tubing firmly onto the machine and the mask. Refit the mask using its guide or run Mask Fit from the MORE menu.
What it means: Something is blocking airflow in the tubing.
What to do: Check the tubing for kinks or anything blocking it, clear it, then press the Start therapy/Standby button to restart.
What it means: The lock switch on the side of the SD card is in the lock position.
What to do: Remove the card, slide its switch to unlock, and push it back in until it clicks.
What it means: The guide lists three likely causes: the machine got too hot, the air filter is blocked, or there is water in the air tubing.
What to do: Let the machine cool if it was somewhere hot, replace a blocked filter, or empty water from the tubing. Then disconnect the AC adaptor and reconnect it to restart.
What it means: Any other system fault number is a device error.
What to do: Remove power and restart the machine. If the error comes back, contact your care provider or ResMed. Do not open the device.
What it means: The machine has detected a humidifier fault. Therapy keeps running, but without heating.
What to do: Check the tub is seated and the tubing is attached, then restart. If the icon stays, contact your care provider; you will be breathing unheated air until it is fixed.
What it means: ResMed says a flashing white light on this button means a system error has occurred.
What to do: Look for the system fault message on screen and follow the matching fix above.
No matching code. Check the exact text on the screen, or see the troubleshooting section on the machine page.
Last reviewed October 11, 2026. How we research · Report an error