During a hot Eastern North Carolina summer, your AC shutting down is an unwelcome event. In normal operation, an air conditioner should cycle on and off two or three times an hour to keep the indoor environment cool. An AC cycling more frequently than that — or worse, shutting off and staying off — quickly becomes obvious, as the house becomes uncomfortably warm.

Causes of and cures for an erratic AC shutting down range from simple matters to more complicated issues that require professional service. Here are some examples:

• Thermostat placement. If your AC thermostat is installed in a room that is typically colder than other parts of the house, the unit may turn off the air conditioner more often and cause it to stay off for longer periods. This may mean that the AC doesn’t run long enough to keep other rooms comfortable. A thermostat should be placed in a central hallway in the home where air circulates freely to try to avoid your AC shutting down.
• Clogged air filter. A dirty system air filter reduces air circulation through the indoor AC evaporator coil. This causes ice formation on the coil, strangling system airflow and eventually triggering an automatic shutdown. Ask your HVAC contractor for more information about the proper replacement interval for the air filters in your home.
• Low refrigerant. Insufficient refrigerant charge is detected by a sensor in the compressor, which then causes the unit to turn off rapidly before adequate cooling is produced to meet thermostat settings. This is called “short cycling,” and it requires professional service to repair refrigerant leaks and then restore the system to proper refrigerant charge.
• Mechanical/electrical issues. Sensors to prevent an overflow of liquid condensate may shut off the AC if the condensate drain pipe is clogged. The run capacitor that delivers a jolt of electricity to start the AC compressor can weaken over the years and stop providing enough current. A central AC typically incorporates two separate circuit breakers to make the system work; a tripped circuit breaker can shut down the whole system.

For all your HVAC needs, contact the pros at Jackson & Sons, serving Eastern NC since 1974.