The vacuum breaker/water line on my lawn irrigation system is extremely noisy. When the system turns on to water my lawn, the line and breaker vibrate loudly until the first zone line fills, then the noise level drops to a hum with a bit of a vibration. This repeats as the system steps through each zone. The noise stops when the watering cycle completes. What, if anything, can I do to quiet the system. It is quite annoying.