Does a bad capacitor hum?
Does a bad capacitor hum? So, what exactly is the problem? If your outdoor AC unit is humming but the fan isn't running, that most likely means you have a bad fan capacitor. Thankfully, there's a short-term fix that'll keep you cool until you get your capacitor replaced. How do I stop my furnace from humming? A furnace buzzing noise likely requires a professional to fix, as components need to be replaced. If the transformer box has simply become loose and the transformer itself has not gone bad, it may be possible to tighten it up on your own to...