I have a Carrier heat pump. Yesterday we had freezing rain, and the out side unit froze. This morning, the unit was working, but it was making a loud noise, but the fan was moving. This evening, it is making a humming sound, but the fan is not moving. Does this sound like something that can be fixed? The unit was installed in 2001.

Thank you!

Sounds like the outside motor may be stuck due to ice or the motor is defective. I would turn off unit outside and try to turn the fan blade manually to see if it turns smoothly.

It may be in defrost mode.

Every 30,60 or 90 minutes of run time(depends on what your defrost time is set at) Your heatpump will check to see if it has ice on it. If so it will go into a defrost mode-- Out side fan stops, loud swishing noise(reversing valve) followed with steam and a loud hum from the unit all is normal. Its trying to remove the ice from the condenser coil. After a few minutes you should hear a loud swishing noise again and the fan will start to run.