The one from 2012 was found and fixed: http://westseattleblog.com/2012/12/the-hum-followup-calportland-installs-second-silencer-hopes-thats-the-fix/ http://west

The one from 2012 was found and fixed: http://westseattleblog.com/2012/12/the-hum-followup-calportland-installs-second-silencer-hopes-thats-the-fix/ http://westseattleblog.com/2012/12/the-hum-followup-calportl... This one started in Summer 2016 and is going 24-7. The only times I've stopped hearing it is when I've gone on vacation; I really need to move. But finding a new place in Seattle is kind of a nightmare right now, and moving to a new city is not without its own complications!