Warm air usually comes from a thermostat setting, a stopped outdoor unit (often a failed capacitor or contactor), a dirty filter or frozen coil, a tripped condensate float switch, or low refrigerant from a leak. Check the thermostat, filter, and breaker once; if that does not fix it, request diagnosis.
Technical Consideration
Symptom to likely cause
| What you notice | Likely cause |
|---|---|
| Outdoor unit silent | Breaker, disconnect, contactor, or thermostat call |
| Outdoor unit hums, fan not spinning | Failed capacitor or fan motor |
| Ice on copper line | Airflow restriction or low refrigerant |
| Water in pan, system off | Condensate float switch tripped |
| Runs constantly, slightly cool air | Low charge, dirty coil, or undersized system |
What can I safely check first?
Confirm cooling mode, a sensible setpoint, a clean filter, open registers, and that breakers have not tripped.
Reset a tripped breaker only once. If it trips again, leave it off.
What are the shutdown clues?
Water near the indoor unit can trip a condensate safety switch. Ice indicates an airflow or refrigerant problem.
If you see ice, turn cooling off and run the fan so it can thaw before a technician arrives.
Why does diagnosis matter?
Several failures produce the same symptom, so measurements are needed before adding refrigerant or replacing parts.
Adding refrigerant without finding a leak is a temporary fix that you will pay for again.
Related services in Wilmington
Local verification resources
Before authorizing work, use the Delaware license lookup. For projects that may require approval, consult the City of Wilmington permit information or the authority serving the property.