When a geo turns off, should it make a gurgle type sound like the water is equalizing, or maybe boiling ? (Open loop) operation is fine, water valve opens, fan turns on, compressor starts. It finishes its cooling and everything turns off. And now I hear a gurgling, doesn't really sound like boiling, but could be. If it was, wouldnt there be bubbles working there way through on the next start up ? It lasts maybe 30 seconds or so. It could have always done this, I'm not sure, I just happened to notice it. Is that a normal thing ? No bubbles in the outflow .