How to Fix a Carrier AC Blowing Warm Air

Warm air from a running system usually means a clogged filter, an iced evaporator coil, a dirty condenser, or a tripped condenser breaker.

High risk — mains voltage, gas, or refrigerant. Stop and hire a pro if unsure.

Tools

Step 01
Check the thermostat
Set the mode to Cool and the fan to Auto, then lower the setpoint at least five degrees below room temperature and listen for the outdoor unit to start.
Step 02
Replace the air filter
Slide out the return filter and install a clean one with the arrow pointing toward the furnace or air handler. A blocked filter freezes the coil.
Step 03
Thaw an iced coil
If the refrigerant line or coil is frosted, switch the system to Off and the fan to On for two to four hours until all ice melts.
Step 04
Reset the outdoor disconnect
Confirm the outdoor breaker and the disconnect box beside the condenser are both on. Reset a tripped breaker once and no more.
Step 05
Rinse the condenser
With power off at the disconnect, hose the outdoor coil from the inside out and clear leaves and grass so at least two feet of space surrounds the unit.
Step 06
Call a pro if it stays warm
Persistent warm air after these steps points to low refrigerant or a failed capacitor or compressor, which require a licensed HVAC technician.

No. Refrigerant is sealed, does not get consumed, and low charge means a leak. Handling it requires EPA certification.