The AntsCanada Ant Forum's

my queen has 6 workers and some brood. i have tried and failed to change the testube and water when it was low. i put a new testube (the wrong size) in and left it. today i saw that the water had ran out completely and the queen had ventured into the upper part and gone in the new tube (i thought the gap was too small for her to get through but it seems i was wrong.)
i sealed her off in the tube then transferred the workers and everything into a pot, cleaned the old tube and added water (and a drop of honey).
i put them all back into the top part but instead of going down into the tube they ignored the queen who kept trying to climb up instead of going down into the tube (which is behind a red viewing window so i can see them and it is supposedly dark for them)

hard to find a solution for your problem. What antspecies is it? Also that might happen sometimes that the workers just chill in a diffrent spot of the setup although they are supposed to take care of the queen.