Outside shower question.

[FrankC 225]

There’s a small tube on the outside shower receptacle between the hot and cold knobs.  I’ve noticed a few small drops of the winterizing solution dripping out of this tube.  Is that normal?   I don’t see the details anywhere in the instructions of what that little tube is, or where it’s connected to.   Is that small amount of dripping normal?  The ITC webpage mentions that this faucet does have an anti-siphon vacuum breaker feature to prevent backflow to the fresh water tank.  So may be something to do with that.  

 

Edited March 27 by FrankC