Where is my overflow valve? I called Heartland and they're guessing it's a closed system since I can't see a drain tube coming from the underbelly. I filled up the water tank all the way, for the first time, yesterday and was standing right next to it (the monitor said full) and all of a sudden water started dripping from the underbelly (from underneath the metal) by the front door steps and from the underbelly by the water connection. I have a regulator and the PSI was 30. I have an Anderson valve and I removed the wall in the basement and it's not leaking.