Machine and humidifier
CPAP Turns On but No Air Is Coming Out
If the screen lights up but you feel little or no air, therapy may not be started, the hose may be disconnected or blocked, or the filter may be clogged. Press start, check the tube and filter, and look for an error message. If the airflow still will not turn on, the blower may have a fault and your provider needs to check it.
Signs
- Screen is on but no air at the mask
- Very weak airflow
- A tubing blocked or high leak message
- Air only at the very low ramp start pressure
Common causes
- Therapy not started
- Many machines power on to a standby screen. Philips says to press the Therapy button to start airflow.
- Ramp starting low
- Ramp starts at a low pressure and rises over a set time, so air can feel very weak at first. This is normal.
- Blocked or disconnected tubing
- ResMed's AirSense 11 guide shows a Tubing blocked message and says to check the air tubing and remove blockages.
- Blocked filter or water in the tube
- The same guide lists a blocked air filter and water in the air tubing as causes of a system fault message.
- Blower problem
- Philips says if the airflow does not turn on after power and the Therapy button are checked, there may be a problem with the blower.
Fixes to try, easiest first
Press start
Press the start or therapy button. If your machine has an automatic start feature, take a deep breath in and out through the mask to trigger it.
Wait out the ramp
If air is weak but present, ramp may be on. It rises to your prescribed pressure over the ramp time you or your provider set. On the AirSense 11 ramp can be Off, 5 to 45 minutes, or Auto.
Check the hose at both ends
Push the hose firmly onto the machine and mask. Look for kinks under the pillow or a hose pinched by the headboard.
Empty water from the tube
If water collected in the hose from rainout, drain it, reconnect, and restart the machine.
Check the filter
Remove the filter. If it is blocked, replace it with a new one made for your machine.
Restart the machine
Disconnect the power adapter, wait, then reconnect it. ResMed's guide uses this step for several error messages.
Contact your provider
If air still does not flow, there may be a problem with your device. Philips advises contacting your home care provider.
This is an equipment fault for your provider to fix. If you feel short of breath, have chest pain or feel unwell with or without the machine, seek medical care right away rather than troubleshooting the CPAP.
Supplies that can help
The air inlet filter keeps dust and lint out of the machine and your airway; it is a cheap part that needs regular replacement.
The plain hose between the machine and the mask; it wears out and should be replaced on a regular schedule.
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Frequently asked questions
Why does my CPAP feel like it is barely blowing air?
Ramp may be on, which starts at a low pressure and builds. If air stays weak after the ramp time, check the hose and filter.
What does Tubing blocked mean on a ResMed machine?
The AirSense 11 guide says the air tubing may be blocked. Check it for blockages or water, then press the start button to restart.
Can I use my CPAP with a torn hose while I wait for a new one?
A torn hose leaks pressure, so therapy will not work as intended. Get a replacement hose made for your machine as soon as you can.
Sources
Last reviewed October 11, 2026. How we research · Report an error