I live in the northeastern US and we just turned the heat on (oil) and this morning I went down to the basement and saw this:
The water is coming from the plumping above something labeled "water expansion tank". In the picture below, you see the green patina forming over the copper pipes above the tank.
- What is a "water expansion tank"?
- What does this tank have to do with my heating system? Is it just coincidence that it started leaking right after turning on the heat, or does the boiler engage the tank somehow?
- What is the likely root culprit here, and how might I diagnose what is exactly wrong with it (and then, subsequently, fix it myself)?