resmed med issue with air

Hi, new to the forum. Hoping someone has some insight. I have a Resmed S9. It's pushing 5 years old. I am due for a new machine in April. That said I went out of town last night and I took the machine apart as per the norm. Put back together at the hotel to use and I could here air passing through it when I breathed in. It lasted all night and kept me up all night. I tried several things to stop it. Its only when I breath in and it's coming from the machine. Now that I am home I did the same process and switched out some tubes, tried a little trouble shooting. When I put my ear near the machine it most definitely sounds like it's coming from the center where the machine connects and I believe right at the tube that connects the air tube that pushed the air through the water tank. I don't see any missing pieces and haven't a clue how to make it stop. I don't think I lost a part that seals anything so I am at a loss. I am worried that I won't be getting the right pressure since mine is set fairly high. Sorry so long. Any ideas how to fix? Thank you.

I can give you a couple of references. I sounds like you may have a leak somewhere. Assuming you have the H5i humidifier, check where the humidifier seals to the machine. Check the seal on the lid of the humidifier. Less likely but check the fittings at the back where the hose connects.

Here is link to the Technical Manual. It has a little bit on maintenance, but not much.

And here is a link to some parts for the machine. You can buy the water tank, the lid seal, and the back hose connection.