I found this forum searching the internet for how to install an expansion tank to my water heater. A thread back in 2006 matched the problems I am having almost perfectly. I realized that the problem may lie in my spinkler system. I did not see the resolution to the posters problem so decided to try a thread myself. Today my expansion tank burst. For the past 3 months roughly i have been hearing a water running noise in my living room directly above where the water enters our house. We just installed a new spinkler system last year but only began using it this summer when we laid sod. I called a plumber to come check out the water noise i had been hearing and was told that our toilet needed the fill valve and fallper replaced, wich we did. The noise lessened some but did not go away. Like the poster last year we also have a terrible noise when the spinklers change zones. I really never thought anything of it until now. So, our sprinkler syster taps into the main water line before it enters the house and before the shut off valve and the pressure regulator valve. We do not have a pressure guage so i do not know what pressure the water comes into the house at. Today the expansion tank burst and before i replace it I wanted to know if the water running noise the loud spinklers and the broken expansion tank were all connected. Anyone's input would be really apprecitated. Hope it all made sense. Thanks.