Problems with an Osmometer - (Oct/26/2009 )

I'm not sure if this is quite the right place for this question, but I wasn't sure where else to put it. I've been using an osmometer (Vapro 5520 by Wescor) and it seems to be broken. It keeps taking readings when the chamber is actually empty. This has happened a few times before, but usually it's just an issue of wiping it dry again and that fixes it right away. That isn't working now. I can't find the manual anywhere and I need to know what I can do. Should I just choose clean test? Or, I'm thinking one of the disks might be stuck inside, is there a way to open it up and see if there's anything stuck? If anyone knows anything about these machines please let me know what I might be able to do. The guy I work for doesn't know how to use it and the only person that used to know has since moved on. Thank you.

do you have the manual?

have you tried contacting wescor customer service?