What to Check Before Calling for AC Repair

• Mode set to Cool, not Fan or Heat
• Set point at least three degrees below current room temperature
• Fan set to Auto
• Display bright and responsive — a blank screen often means a tripped float switch or blown low-voltage fuse
• Fresh batteries if it is a battery-powered model
• Schedule or hold not overriding your setting

Pull it and hold it up to a light. If light does not pass through, replace it before doing anything else. Note the direction arrow so it goes back with airflow.

• Check the indoor and outdoor breakers at the main panel — a tripped one may not look obviously off
• Confirm the outdoor disconnect box near the condenser is engaged
• Check the switch near the air handler, which is often mistaken for a light switch
• If a breaker trips again immediately, stop and leave it off — that is an electrical fault

Look at the insulated copper line where it enters the indoor unit and at the coil if it is visible. Frost or ice means turning cooling Off and the fan On, then letting it thaw for two to four hours before any restart.

• Check for water around the air handler or in the emergency pan
• Look for ceiling stains below an attic unit
• Confirm water is dripping from the outdoor drain termination on a humid day
• A full pan usually means the drain is clogged and the safety switch has shut the system down

• Is the fan on top spinning?
• Do you hear a hum with no fan movement? Note that — it points to a capacitor or motor
• Is the coil matted with grass, dust, or leaves?
• Is anything blocking airflow within two feet of the cabinet?

• Your address and whether the equipment is in an attic, closet, garage, or on a roof
• Brand and approximate age of the system, if known
• What the thermostat reads versus what you set it to
• Exactly when the problem started and what changed
• Whether the outdoor fan spins and whether the indoor blower runs
• Any ice, water, odors, or noises you observed
• Any recent work performed on the system