When an air conditioner stops cooling, the first question is whether the fix is simple or whether a part has failed. AC repair in Ruston homes often starts with a few safe checks a homeowner can make in minutes. When those do not solve it, knowing what the common failures look like helps you describe the problem clearly and get the right repair faster.
This guide covers what to check first, the parts that fail most often and why, what you should leave alone, and what an AC repair visit with Mark Johnson & Sons Plumbing includes.
Safe Checks Before You Call
These steps are safe and solve a surprising share of no-cooling calls:
- Thermostat. Confirm it is set to cool, the set temperature is below the room temperature, and the display is working. Replace the batteries if it uses them.
- Air filter. A clogged filter restricts airflow across the indoor coil. Replace it if it looks gray or dusty.
- Breakers. Check the breaker for the indoor unit and the outdoor unit. If a breaker has tripped, reset it once. If it trips again, leave it off and call.
- Outdoor unit. Make sure nothing is blocking airflow around it, such as grass clippings, leaves, or stored items.
- Vents. Open supply registers and make sure return grilles are not covered by furniture.
If the system still does not cool after these checks, the problem is likely inside the equipment.
Common Failures and What Causes Them
Capacitor failure. The outdoor unit uses a capacitor to give the compressor and fan motor a boost when they start. Heat and age weaken it. A failing capacitor can leave the outdoor fan still while the unit hums, or keep the compressor from starting at all.
Contactor problems. The contactor is an electrical switch that turns the outdoor unit on when the thermostat calls for cooling. Its contact points can pit and burn over time, or insects can block them, so the unit never starts.
Low refrigerant from a leak. Refrigerant circulates in a closed loop. If the charge is low, there is a leak somewhere. Low charge drops pressure in the indoor coil, which can make the coil freeze over and block airflow. Adding refrigerant without finding the leak only delays the next failure. Refrigerant service should include locating the leak.
Dirty or frozen evaporator coil. Dust that gets past a filter coats the indoor coil and slows heat transfer. Restricted airflow can let the coil get cold enough to freeze. The evaporator coil may need cleaning or repair.
Clogged condensate drain. The indoor coil pulls water from the air. If algae or debris clogs the drain line, water can back up, overflow the pan, or trip a safety switch that shuts the system off.
Fan motor failure. Both the indoor blower and the outdoor fan have motors that wear out. A failing motor may run slowly, make noise, or stop completely.
What Not to Touch
An air conditioner contains high-voltage parts and pressurized refrigerant. Do not open the electrical panel on the outdoor unit, handle the capacitor, or try to add refrigerant. Capacitors can hold a dangerous charge even with the power off. Refrigerant work requires EPA certification under Section 608 and the right recovery equipment.
What an AC Repair Visit Covers
An AC repair visit with Mark Johnson & Sons Plumbing starts with what you noticed: when the problem began, whether the system runs at all, and any sounds or smells. The technician then checks the system in a logical order:
- Thermostat signal and wiring
- Electrical parts at the outdoor unit, including the capacitor and contactor
- Refrigerant pressures and temperatures
- Airflow, filter, and indoor coil condition
- Condensate drain and safety switch
The goal is to find the cause, not just the symptom. A tripped breaker, for example, is usually a sign of another problem rather than the problem itself.
When a repair is not worth it, such as a failed compressor on an older system, the technician can explain the options, including AC installation.
What to Note Before You Call
A few details help the technician narrow the problem quickly. Note whether the outdoor unit runs, whether the indoor blower moves air, and whether the air from the vents is warm or just weak. Listen for humming, clicking, or grinding, and check for water around the indoor unit. Write down when the problem started and whether it followed a storm, a power outage, or a recent filter change. Those observations often point straight to the failed part and shorten the visit.
When It Is an Emergency
Some situations should not wait:
- A burning smell or smoke from either unit
- A breaker that trips repeatedly
- Someone in the home who is vulnerable to heat and the house is getting hot
Turn the system off at the thermostat and call for emergency AC service.
Reducing Repair Calls
Most repairs trace back to dirt, heat, and wear. Regular filter changes and seasonal AC maintenance keep coils clean and catch weak capacitors and worn contactors before they fail. ENERGY STAR's heating and cooling guide and its maintenance checklist list what to do and how often.
Schedule AC Repair in Ruston
If your air conditioner is blowing warm air, not starting, or tripping breakers after the simple checks, schedule AC repair in Ruston with Mark Johnson & Sons Plumbing. Visit the Ruston service page or book a time to get the system diagnosed.