Have just about a new 2 1/2 Ton American Standard unit outside. When the tempature approches 90 degrees,a loud vibrating noise,that transmits into the House,in the room only,adjacent to the Unit. Is it imperative that the Unit be mounted a foot from the wall,which it is only about 6 inches? Thanks for any help..

Something loose or out of balance

How new and is it still under warranty? Did it always make this noise from day one or did it just start? Most compressors are pumping the feron at a very high pressure and a small valve near the A coil releases that pressure so it could he the high pressure line coming into the house is rubbing on the siding or floor joist. This would be an install error and should b covered

Thanks for the information. Sounds like a vibration,& that it could be the line hitting,or something inside the unit Panel,& is most prominent inside the bedroom. The A/c unit did not make this noise when installed.

How long ago was the install?