Intermittant Noise coming from water line

[LannyV]

My daughter bought a house that did not have an expansion tank installed so before she moved I install an expansion tank. Now since this was installed before she lived there we don't know if this noise existed before the expansion tank was installed. The noise is not there all the time. It only appears to be present during the summer months. During the winter it is never heard. Turning on hot or cold water does not affect the sound.

https://www.facebook.com/video.php?v=10207372059338198

 

[Reach4]

Feel pipes and tank. Does it feel strongest at some point?

On a horizontal pipe. Grip the pipe firmly with two hands separated by a bit. Is the vibration stronger on the left hand or right?

Consider turning off the power. Does that buzzing stop?