How to Troubleshoot Problems With Central Cooling Units

Ensure that you've had routine maintenance services performed on your system. If not, you may simply need to have the central unit cleaned. Check to see if the reusable air filters for the system are clean and not clogged with dirt and dust. If they are dirty, replace them for a more efficient unit.

Set the thermostat on a temperature that is cooler than the outside temperature. The system won't turn on if the air in the house is cooler than the air outdoors.

Check the machinery for your cooling unit. If the fan in the unit outdoors is not operating you may have a broken belt. Check the circuit breaker for the A/C system as well. If it has tripped, flip it back on. If it trips again you may need a new breaker. Inspect the exposed wiring on the air handler for signs of damage or wear.

Check the condensate reservoir on your air handing unit to make sure it is not full of water. If it is full, the air conditioner will turn off automatically. This means the pump for the system is not working and it requires a service call.

Put a hand on one of the vents. If you don't feel air blowing you may need a new blower motor or control board, requiring a service call. If the blower is running, look for signs of frost or ice around the A/C unit. If so, turn off the A/C for a few hours but keep the blower running. This ice should melt.

Turn the A/C back on. The copper line on the outside unit should be cold. If not then you may need to add Freon to the system; this requires a service call.