what valves to turn on and which ones not

[wannagetrdone]

Hi guys i stated in a previous post I'm totally new to rv living. My question is I have two valves on the back side of my water heater. One is higher up one is lower. Which one do I need to turn on and which one to turn off. I removed the top one because one of the twist connections was broke it started gurgling and water ran out my storage compartment through one of two lines I have in there that doesn't seem to go to anything. Thanks