Solutions for Common Central Air Conditioning Unit Issues

A central air condoning system outside a brick house.

A central air conditioning unit is an integral part of a modern home. During the summer months, your Heating, Ventilation, and Air Conditioning, or HVAC unit, maintains indoor temperatures to desired comfort levels. HVAC systems cool and circulate conditioned air throughout the home. However, problems may arise that cause your HVAC system to malfunction.

Familiarizing yourself with common HVAC issues may allow you to restore service. Before troubleshooting your HVAC system, always err on the side of caution and turn off the power.

Unit Fails to Turn On

Many problems can prevent your HVAC system from turning on. When your unit fails to activate make sure the thermostat is set to cool versus heat. Then adjust the thermostat's temperature setting to a degree lower than the inside temperature. Most thermostats incorporate an inside temperature indicator somewhere on its display. Locate and identify the HVAC system circuit breakers. If the breakers are in the off position, a malfunction has occurred. Resetting the breakers might activate the system but could cause more damage. You should contact an HVAC contractor immediately should this situation arise.

No Cool Air

Air conditioner outside a brick house.

When your HVAC fails to produce cool air, steps you can take on your own may restore service and prevent a costly service call. Start by setting the thermostat to the cool position. Verify the thermostat's temperature is set to a degree lower than room temperature. A clogged air filter can severely restrict air flow to the evaporator coils reducing the unit’s ability to cool and circulate air. Clean or replace a dirty HVAC filter.

Unusual Noises

Air conditioning units make a distinct sound when activated. When you notice your HVAC system omitting an unusual sound, determine if the sound is coming from the inside air handler or outside condensing unit. An HVAC system utilizes many fasteners to secure components and shrouds to its applicable housing. If a fastener becomes loose, it could cause a rattling sound. This applies to both the inside air handler/evaporator and the outside condensing unit. When the noise is specific to the outside unit, visually inspect the shroud covering the fan motor. Often, debris falls through the shroud and into the fan motor causing an unusual noise.

Leaking Evaporator

Air conditioner outside a brick house with blue shutters.

A leaking evaporator coil can lead to costly home repairs and requires immediate action. Start by turning off the thermostat and circuit breakers powering the HVAC system. The drain line diverts condensation produced by the HVAC system outside your home. When your unit is running, you should notice water dripping from the outside line. At the very least, the ground area near the end of the line should be wet. If no water is present, you may have a blocked condensate line and service is required.

Some HVAC systems utilize a condensate pump. It is used to pump the condensation outside the home when gravity applications are not applicable. A condensate pump can fail over time, allowing condensation to build up inside the evaporator until it eventually spills out. An evaporator incorporates a drip pan where condensation is collected and diverted to the home's exterior. The pan can deteriorate over time, allowing condensation to leak from the unit which must be replaced. Ice buildup inside of an evaporator coil can cause water to pool on your floor. A simple cleaning or replacement of the air filter may remedy this problem. However, it may also be a sign your HVAC system is low on freon and requires immediate service by a licensed professional.

An HVAC system needs servicing twice a year. Regular HVAC maintenance is essential to maintaining an efficient and long-lasting system.