Air conditioner Troubleshooting Tips

If your system isn’t running:

Check to make sure your control or thermostat is set in cooling mode. Make sure the temperature is set cooler than the current indoor temperature.

If it isn’t, your system won’t know to provide cooling.

Make sure your outdoor condensing unit is running. If it is not running, make sure the breakers in your home’s breaker box or electrical panel are in the ON position.

Check the main power switch for your outdoor unit, usually found within a few feet of the unit in a box mounted to the exterior of the house. Make sure it’s in the ON position.

Ensure that the blower motor in your furnace or fan coil is running. If the system is set for cooling, the blower motor should be running. If not, check to make sure your indoor unit switch is in the ON position.

If your system isn’t cooling enough:

Check the filter for buildup. If you have one-inch-thick furnace filters, a once-a-month change is recommended. Two-inch-thick filters – and other high-capacity pleated filters – usually only need to be changed every other month, depending on the type. If you don’t change it, the filter will eventually block the proper airflow and cause your outdoor air conditioner unit to shut down.

Check all return air grilles to make sure they are not blocked. Return air grilles are larger and are located on a wall or the ceiling in newer homes. Older homes frequently have return air grilles on the floor.

Check all supply registers to make sure they are open and blowing air.

If you still don’t feel the flow of cool air or your system is under-delivering, it’s time to contact your local Carrier expert for service.

Other signs that indicate a service call may be in order:

• Your system is struggling to keep up and seems to be turning itself on and off frequently.
• Your indoor summer humidity levels seem unusually high.
• You hear your indoor-unit fan coming on, but the air from the registers isn’t cool or the fan is turning on and off more frequently than usual. NOTE: If your system control has a “Constant ON” feature, you will not always feel warmth, even though air may be blowing.

If your system isn’t running:

Check to make sure your control or thermostat is set in the HEAT position. (You’d be surprised; often that’s the problem.) Make sure the temperature is set warmer than the current indoor temperature. If it isn’t, your system won’t know to provide heating.

Ensure your furnace’s power is on. Try turning the fan to ON using the fan switch on the control or thermostat to test for power to the furnace.

Check the circuit breakers in your home’s circuit breaker box (electrical panel) to make sure they’re in the ON position.

Check the furnace power switch to be sure it’s in the ON position (it looks like a light switch on a gray box located at the furnace).

System not heating enough: 

Check the filter for buildup. If you have one-inch-thick furnace filters, a once-a-month change is recommended. Two-inch-thick filters – and other high-capacity pleated filters – usually only need to be changed every other month or less, depending on the type. If you don’t change it, the filter will block the proper airflow and strain your furnace.

Check all return air grilles to make sure they are not blocked. Return air grilles are larger and are located on a wall or the ceiling in newer homes. Older homes frequently have return air grilles on the floor.

Check all supply registers to make sure they are open and blowing air.

If you still don’t feel that wonderful rush of warmth throughout your home, it’s time to contact your local Carrier expert for service.

Other signs that indicate a service call may be in order:

You hear your indoor-unit fan coming on, but the air from the registers isn’t warm or the fan is turning on and off more frequently than usual. NOTE: If your system control has a “Constant ON” feature, you will not always feel warmth, even though air may be blowing.

Before you request a service call for your ventilator:

Check the main power disconnect switch. Verify that the circuit breakers are ON or that fuses have not blown. If you must reset breakers or replace fuses, do so only once. Contact your Carrier expert for assistance if the breakers trip or the fuses blow a second time.

Check for sufficient airflow. Check air filters for accumulations of large particles. Check for blocked exhaust air grilles or ductwork. Keep grilles and ductwork open and unobstructed.