whistling machine on inhale. suggestions?

[lebowski8]

I have a M Series Pro C-Flex CPAP Machine. I've used it every night since spring 09, so over 800 nights now.
I own this machine, paid out-of-pocket cash. this model is no longer in production.
Anyway, I've recently noticed a whistle each time i inhale. i washed the filter, no change. i switched masks to test that it wasn't the mask making the noise. I guess it still could be the hose, haven't tested that yet. so, i find this sound pretty annoying.

is the machine ready to die?
do you have any ideas how to sound proof without blocking air intake?

thanks in advance!

[slapmeawake]

When my mask does this it usually means I have water droplets somewhere in the mask. Check and make sure its dry and also turn down the humidifier setting if you are getting rainout. Hope this helps.

[BanjoPaterson]

I believe machines can change their sounds through use. My S8 II, which seemed to have an annoying noise on exhale when I first got it, its now nearly silent after 3000 hours usage (and has been relegated back to my primary machine); and my S9, originally quieter, now is making slight wheezy noises on exhale and has been demoted to backup and travel machine.

800 nights has got to be around 6000+ hours, so I wouldn't be surprised if the fan dynamics have altered.

However, during my S8's annoying whistle phase I did find that placing the CPAP on the floor beneath me on the bed did reduce sound at the cost of length of hose.

My two cents.

[Pugsy]

On the remote chance it is related to C Flex setting, try turning C Flex off and/or changing the setting.

I do have a M series machine that I used until I got the PR S1 machine but not as many hours on it as you have. It is a quiet now as when I first used it.

Do you have a backup machine available just in case this noise is a forerunner for serious mechanical issues?

[PUFFER]

My PR1 was making that noise in the first weeks that I had it. I lifted it off the floor and put it on a table more even with the mattress. Make certain that you aren't lying on the hose or that a heavy blanket or pillow isn't on top of the hose. It may be vibration from something lying on or touching the hose. Once I cleared the path for the hose, the noice stopped.

[bailachel]

My PR1 started making that noise after about 18 months of use. I tried: replacing the mask, replacing the hose, changing the filter, removing and replacing the humidifier tank. None of this worked. The tech at my DME had me remove the humidifier all together and we confirmed that the noise was coming from the blower. Luckily for me, my machine was still under warranty and they replaced it. If the whistling noise that your machine is making is also from the blower, maybe you can find a way to muffle it. I remember seeing a thread where people seemed to have put their machines in a box or a nightstand drawer with a cut out for the hose.

[lebowski8]

My PR1 was making that noise in the first weeks that I had it. I lifted it off the floor and put it on a table more even with the mattress. Make certain that you aren't lying on the hose or that a heavy blanket or pillow isn't on top of the hose. It may be vibration from something lying on or touching the hose. Once I cleared the path for the hose, the noice stopped.

Thanks, this suggestion pointed me in the right direction. i put a thin cotton hand towel under the machine, which i keep on the bottom shelf of a solid wood nightstand. this seems to have eliminated the whistle.