A humming outdoor unit with a fan that will not turn is the call we get most in July in Palo Alto, 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.
For winter breakdowns, see Furnace Repair.
Warning Signs for AC Repair
The sooner you notice these red flags, the easier and cheaper the fix. Watch for these telltale signs:
- An AC that turns on and off every few minutes but never cools down the house
- Room-temperature air from the registers even though the AC is running
- A hiss or gurgle from the lines, a common sign of leaking refrigerant
- Cooling bills climbing while the house stays sticky and warm
- Clicking or humming outside with no fan movement
- Water leaking around the indoor unit or from the ceiling below it
- Ice on the refrigerant lines or a frozen indoor coil
- Breaker trips or a burning odor at startup
Don't Wait for a Total Failure
Left unchecked, even a small fault or temperature swing often signals a system working its way toward a breakdown. At the first hint of a problem, call (650) 220-0821 for a fast inspection.
