giving wall wetting condition using field function
 

I have a doubt regarding wall wetting (multi-phase simulation). The initial condition is like, the whole domine is filled with air and rack(imported geometry) is covered by 0.7 mm thickness of water. I have defined the field function for air and water. But when I initialize the solution both rack and the outer walls are getting wet. I have attached some pictures. could some please help me to give a specific definition.

I have used field function for air as $WallDisntace < 0.00007 ? 0:1
and for water $WallDisntace > 0.00007 ? 0:1