I have a closed hydronic loop with no obvious leaks in a boiler heating system. The expansion tank is quite old. Lately I noticed the pressure dropping even when the circulator is not circulating. What starts out at 15 psi will be down to 7 by the end of the day. There are no known leaks anywhere in the piping. While the expansion tank seems to be the culprit by a process of elimination, some signs point otherwise. For example, when I let water into the system the gauge rises slowly as if the bladder is expanding. Also the top of the tank is warm (when the therm calls for heat) and the bottom seems cold which suggests the bladder isn't leaking.. Before I replace the tank, could someone give me their thoughts on this? I sincerely appreciate your help. Thanks. Frank
- posted
12 years ago