Refer to manual for all questions, but for common problems see notes below:

If you are getting bad results, you may need to clean out the frits in the glassware.
Use Chromerge to clean the frits - leave it overnight, rinse thoroughly, and dry in an oven.

Another reason for getting bad results would be old KOH in the tube. You should replace this solution once it becomes frothy.

Check all connections and seals for leaks.

Check that all the traps are in the correct order and are connected in the correct place - always connect from the top of one trap to the thin section of the next.