Hello Guest, Welcome to Apnea Board !
As a guest, you are limited to certain areas of the board and there are some features you can't use.
To post a message, you must create a free account using a valid email address.

or Create an Account


New Posts   Today's Posts

[Equipment] Cpap not blowing
#1
My cpap machine (DeVilbiss) blows pressure when the mask is off, but when I put the mask on, it stops blowing. What is wrong with my machine?
Post Reply Post Reply
#2
Your machine is designed to supply enough flow to provide therapy pressure. The only airflow you should feel is from the exhaust vent on the mask or a leak.
Post Reply Post Reply
#3
It does not blow pressure when the mask it off.  It blows volume trying to create pressure (which is not possible as the mask is off).  Once you put it on, the volume reduces to maintain the configured pressure.  Unless your machine is shutting off when you put the mask on, it is working correctly.  If it shutting off, then there is a problem with it.  Get it serviced or replaced.
Post Reply Post Reply


#4
Hi WillyBilly,
WELCOME! to the forum.!
I hope you figure out what's wrong with your machine, hang in there for more responses to your post.
Good luck to you.
trish6hundred
Post Reply Post Reply
#5
I often check the vents to see if my machine is working. It has always been working fine.

Post Reply Post Reply
#6
(02-25-2017, 04:53 PM)WillyBilly Wrote: My cpap machine (DeVilbiss) blows pressure when the mask is off, but when I put the mask on, it stops blowing. What is wrong with my machine?

There's nothing wrong. When you have the mask on your face it creates an obstruction and this allows the pressure to build in the hose. When you take the mask off you remove the obstruction and the pressure in the hose drops. This causes the machine to spin the fan faster in a futile attempt to raise the pressure. If you leave the mask off long enough the machine will likely give up and shut down.
Sleepster
Apnea Board Moderator
www.ApneaBoard.com


INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
Post Reply Post Reply


#7
An easy test is to lift the mask slightly from your face. If the machine is blowing you will both hear and feel it. If the machine is not blowing you will feel as if you are suffocating.
Post Reply Post Reply
#8
Your airway and the hose from the machine (ignoring for the moment your face mask) are a closed system. As such the machine will only blow until that closed line fills up until the pressure is equal to or greater than the pressure the fan generates. Now if it were entirely closed you would soon top breathing because of too much carbon dioxide in the airway. And that would kill you.

So, to prevent that, your mask has an intentional built in leak so the carbon dioxide you breath out can be blown away. With most masks you can feel this by putting your hand in front of it in the right spot.

Think of blowing up a balloon. When the balloon is deflated your breath goes into the balloon, but when the balloon is as fully inflated as it can be then you can't blow any more air in no matter how hard you try. Or else, it will pop, of course.

Or take a short 1/2" pipe, cover the other hand with your hand and blow. No matter how hard you blow once the pipe is pressurized by your breath no more air will flow into it.

The idea of a CPAP machine is to pressurize your airway so the difference between the inside pressure and the outside pressure will cause it to "inflate" slightly, enough so the airway stays open. Once the pressure is high enough for this no more air will flow into your airway from the CPAP machine even though it will continue to blow so that your airway remains pressurized. What it will be then doing is preventing the pressure in your airway from dropping back down so that your airway stays open.
Ed Seedhouse
VA7SDH

Your brain is not the boss.

Post Reply Post Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  S9 vpap asv defect? stops blowing for 0.5 sec and resumes lv3101 7 759 05-04-2016, 09:07 PM
Last Post: klv329
  Blowing out extra air kally 4 990 09-28-2015, 01:33 PM
Last Post: Sleeprider
  Intellipap blowing too much air MissApnea2000 3 2,484 06-12-2015, 10:12 PM
Last Post: OMyMyOHellYes
  [CPAP] First NIght, Can't keep air from blowing out mouth Jefflex 9 9,327 04-21-2014, 06:20 AM
Last Post: herbm
  CPAP Blowing My Cheeks Up? Bruno2 3 5,968 04-06-2014, 01:21 AM
Last Post: PaulaO2
Sad [CPAP] My machine is not blowing fully jenniepepsi 14 4,708 03-21-2014, 10:36 PM
Last Post: trish6hundred
  [Symptoms] Blowing air from mouth mtyakker 9 10,424 07-14-2013, 10:52 AM
Last Post: ellen1159

Forum Jump:

New Posts   Today's Posts




About Apnea Board

Apnea Board is an educational web site designed to empower Sleep Apnea patients.

For any more information, please use our contact form.