I started noticing this about a year ago. There are times my AC, part of my HVAC unit, would drop into fan mode and stop cooling before the set temp has been reached. When my AC is on, I can hear an extra noise, something like a buzzing almost. That's when the cooling is happening. But at times, this would stop and the unit would go into fan mode and my house doesn't cool down at that point. I would have to turn the unit off and let it sit for a few hours. Then when I turn it on again, the AC will kick in again, and I won't encounter this issue again for a couple of days until it happens again. I do notice that this happens more often when it's extremely hot outside. Can anyone shed some light or observations on this? Thanks.