Recently I installed the whole irrigation system, the contractor recommended this controller for me and got the wiring down. It was great, finally I have my own yard, I was planning to grow some violence and some vegetables. But there was something unpleasant, I heard noise from the pipes every time the controller watered, actually I heard it the first this system run, they told me this would get better, don't worry about it. Now it's been two weeks, I still heard the noise. Totally not an expert, so I googled it and I know it was called "water hammer." caused by the water pressure in the pipe. It turns out I need to buy more stuff to minimize it, like air release valves, quite frankly, this system cost me a lot and I don't wanna pay for another project. Can anybody give me some free advice?