My outside AC unit makes a ringing noise before it kicks on. Do you know what might be causing this noise?

Question

My outside AC unit makes a ringing noise before it kicks on. Do you know what might be causing this noise?

Answer 1

nope never heard that b4

Answer 2

The fan blade may be hitting something - metal fan blades make a ringing sound when they are slightly touching another object. This can happen when the blade is loose on the shaft - initially, it strikes the obstruction, but as it spins to full speed, air pressure pushes the blades clear.

You can use the outdoor safety disconnect switch to shut down power to the unit, then remove the maintenance cover; slowly turn blade by hand to see what it is hitting and check the set s***w to see that it is tight.

As this could be disasterous if the fan should turn on, you may want to shut off the associated circuit breakers to disconnect power, but you  MUST also  have the unit shut down from the disconnect switch within sight of the unit. That way, you can be sure that an unsuspecting other won't turn the power back on while you are working.

Answer 3

You could be hearing the compressor starting before the fan.

Is this noise different from what you normally hear from it?

If so you need to have a technician out to diagnose before it gets worse.