I have a Rudd unit. The condenser is outside and the unit is in the basement. It is a dual heat/air unit. Upon returning home this afternoon, I noticed it was hot inside the house. Changing the thermostat setting didn't help kick the unit on. I flipped the breaker, the unit acted like it was going to fire up, and quickly stopped. I changed the thermostat out, but that didn't help. When I turn the breaker switch on, the condenser fan runs, but the motor doesn't fire up. What could the problem be? Please help... I have six children and it is quite unbearable to them inside. Thank you!

Check to be sure the contactor in the outdoor unit is pulling in. Then check power wires going to the compressor. Then test/check the compressor capacitor. If all else fails call for service.

Quote: the condenser fan runs, but the motor doesn't fire up.
Are you talking about the blower motor in the furnace/airhandler?or outside not running