I went to a repair yesterday for a previous customer. I repaired her system at the previous home but at the brand new home she had a full landscape job, which I don't do, so they also did the irrigation. This landscaper/sprinkler contractor did most the homes in this neighborhood. Well she had problems soon after the system was in. Drip zone was always running and everything was flooding at back end of property. Contractor replaced diaphragm a few times and it stll did the same after a while. I don't think he every flushed the valve out as there was sand inside when I fixed it. The flooding issue - the homeowner kept telling him there was a leak in the system. "NO, no, no. It is just sloped that way". Well of course I found the leak. Landscaping pin straight through the poly pipe. It wasn't hard to find. I'm not trying to keep bringing the same issue up, but he didn't know what he was doing. One zone was also stretched at about 17 GPM. The heads have hardly any resistance when you push down. The homeowner asked about adding heads and there is no way. The system is still under warranty and she paid ME to fix it because the other contractor couldn't. That has happened many times in the past years. I'm not trying to be arrogant, but you have to learn what's going on before you jump right in.