After only 9 weeks I had to replace my defective S9. The S9 ResMed CPAP is defective. Exchange yours now. After only 9 weeks the fan started making loud noises on inhale/exhale. Lights stayed on and bright. I took it in to American Home Patient and they were terrific. They did some research and discovered there are a lot of issues with the original firmware/software. The updated exchanged model is quiet and the lights go out in under a minute. So if yours is the original, I suggest you replace it under rental or warranty. I have only used it two nights so we'll see how it goes. Garry