Valve problems

I been wearing a Cpap for over nine months. But lately I been having trouble with my valve closing when I breath out. It's not a continuous thing but it comes and goes. When this happens its so hard to breath. I saved my old piece when I received my new one and I never had trouble with it. I tried it and it also does the same thing. Any suggestions?

It would help to know what mask you are using. In general, the anti asphyxia valve automatically opens if the flow generator pressure falls, such as during a power failure, allowing the patient to breathe room air. It should be closed when the CPAP is running.

As LSAT states the anti asphyxiation valve should stay closed when the machine is running. Your difficulty exhaling may be due to your machine settings. Please register and put your equipment in your profile so we can better help you. wiki/index.php/Registering_Equipment_in_User_Profile

In short, the only time the valve will open is when the machine is OFF.
Your exhaled air and any excess air from the machine passes through the vent holes in the mask, usually at the front.
Pass your damp hand in front of the mask while the machine is running.
You will feel a breeze chilling your hand. There is way more air than you exhale, which is normal.
If you look closely at the mask, you will see the vent holes. Keep them clean and never cover them.