This evening when I fired my boiler I noticed that there was moisture on the inside of the glass of the gauge on my storage tank. It's about 15 years old an I have never seen this happen before so I am concerned. The water temp was down to about 120 when I fired the boiler and now that the temperature is up the moisture is gone. Does anybody think that a failure is imminent here? Can these things spring a serious leak? I'm thinking about going into town tomorrow and picking up a new one.