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I need some suggestions... I have a newer system (3 wks old) and the backyard zone has 6 rotor heads on it. The problem is the one right outside our bedroom window is the only one that bursts air (like when you turn a garden hose on) periodically for the first 5-7 minutes the zone is running. This head is the lowest one in the zone, so I don't know if that makes a difference or not. At 4am in the morning, it will walk you right up with the loud air bursts. I have irritrol 450 rotors. Is there any way to resolve this??? I would expect a burst or two, but not multiple ones for 5 minutes or more. It does spray plenty of water during that time, it just spits out air bursts (loudly) every 15-30 seconds. I have about 80psi coming out of the house so I don't think it is starved for pressure. None of my other zones do this... Ideas???