My Last Pump Sounded Like Generator Running And I Bet It Kept My Neigborsfrom Sleeping But That Thing Kept Working So I Kept Them Up Every Night Until One Day I Shut It Off And It Would Not Come Back On Because The Fan Finally Locked Up On It. I Never Knew What The Problem Was But It Would Also Get Hot After Running Awhile So I Would Turn It Off And Pour Water On It Concerned It Might Cause A Problem But I Ran It Alot Before I Bought A New One . Just Be Careful If It Is Getting Hot While Running .