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Cooling

Why Is AC Blowing Warm Air at Home?

An air conditioner blowing warm air is one of the most frustrating problems a homeowner can face — especially during a heat wave. Here are the most common causes and what to do about each.

Check the thermostat first. Make sure the thermostat is set to 'cool' and the temperature is set below the current room temperature. Also check that the fan is set to 'auto' rather than 'on' — when the fan is set to 'on,' it runs continuously even when the system isn't actively cooling, which means it blows uncooled air between cooling cycles.

Check the circuit breaker. In some systems, the indoor and outdoor units are on separate circuits. If the outdoor unit's breaker has tripped, the indoor fan will run but the system won't cool. Check both breakers.

Check the air filter. A severely clogged filter can restrict airflow enough to cause the evaporator coil to freeze, which paradoxically results in warm air from the vents. Replace the filter and let the system thaw if ice is present.

Check the outdoor unit. Make sure the outdoor unit is running. If the condenser fan isn't spinning or the unit isn't running at all, the problem may be a failed capacitor, contactor, or compressor — all of which require a technician.

Low refrigerant. If the system is running but not cooling, low refrigerant is a common cause. This requires a technician to find and repair the leak and recharge the system.

Dirty condenser coils. The outdoor unit's coils can become coated with dirt and debris, reducing their ability to release heat. This is addressed during annual maintenance.

West Coast Air Conditioning diagnoses and repairs AC problems throughout Calaveras and San Joaquin County. Call (209) 598-8889.

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