A humming outdoor unit with a fan that will not turn is the call we get most in July in Daly City, CA, and the cause is usually a failed run capacitor. That inexpensive component starts the compressor and fan, fades for years without complaint, and then quits under peak load. It is far from the only suspect, though. Contactors pit and stop passing clean power, condenser fan bearings dry out, small refrigerant leaks drain away cooling capacity, and evaporator coils ice over when a clogged filter strangles airflow.
When the heat goes out, see Furnace Repair.
Warning Signs for AC Repair
Spotting the early warning signs lets you act before the problem gets expensive. These are the signals our technicians see most often:
- Vents blowing air that is barely cooler than the room
- Higher summer bills even though the house still feels warm and humid
- Frost or ice forming on the copper lines or the indoor coil
- Water leaking around the indoor unit or from the ceiling below it
- Clicking or humming outside with no fan movement
- An AC that turns on and off every few minutes but never cools down the house
- A hiss or gurgle from the lines, a common sign of leaking refrigerant
- A burning smell or repeated breaker trips when the AC starts
Don't Wait for a Total Failure
Most HVAC failures start small, a weak capacitor, a squealing blower, a system that runs a little longer each week. If you notice any of these signs, call (650) 220-0819 for a prompt inspection.
