AC Troubleshooting Guide for Homeowners

Air conditioners are complex devices that require HVAC professionals to install, repair, and maintain.

If you don’t know one end of a screwdriver from another, even small issues require professional know-how.

However, if you’re a little more adept at DIY, you may be able to troubleshoot your AC and fix minor problems with a few basic steps. 

Most homeowners can handle changing an air filter or a thermostat battery, or resetting the breaker switch. This can prevent the cost of emergency AC repairs and save you time and money. Do not, however, attempt more complex DIY AC repairs as there are safety risks.

Here are seven simple AC troubleshooting steps if your AC runs into problems…

1. CHECK THE THERMOSTAT

It’s surprising how many air conditioning problems start with a simple thermostat. 

The thermostat regulates the temperature in the home according to the settings. Smart thermostats, which are common in modern HVAC systems, can do a lot more than regulate temperatures and can be controlled with a phone, tablet, or another connected device.

Troubleshooting the thermostat usually requires:

If neither of these steps fixes your thermostat problem, call a professional to check the thermostat wiring or recommend a replacement device (thermostats don’t last forever).

2. CHECK DOORS AND WINDOWS

The home environment can also create air conditioning problems, especially if your AC unit was not correctly sized from the start.

Keeping windows and doors shut when the AC is on may seem obvious, but we’ve been to plenty of houses where doors and windows are open with the AC on full blast.

This causes the AC system to overwork, and it may struggle to cool your rooms properly. Over time, electric bills can rise, and the lifespan of your unit can shorten.

If your house receives a lot of direct sunshine and lacks proper insulation, it may pay to consider curtains or shades and weatherproofing properly around doors and windows.  This helps keep the cold in and the hot out, and can be more cost-effective than investing in a new AC unit.

3. CHECK FOR A TRIPPED CIRCUIT BREAKER OR BLOWN FUSE

If your AC won’t turn on at all, it could be a thermostat power problem or an issue with the power supply to the unit. 

Sometimes, circuit breakers trip due to overloading. This is especially common during Florida storms. Find the electric panel (you may have a dedicated panel for your AC), and flip the breaker to the OFF position, then back to ON.

Wait a few minutes and try turning on the AC again to see if it works.

If you live in an older home without a breaker, check that a blown fuse doesn’t need replacing. To do this, find a multimeter and follow these simple steps:

1. Safety first: Ensure the power is turned off at the main breaker before removing any fuses.
2. Set the multimeter: Turn the dial to the lowest Ohms (Ω) setting or, if available, the Continuity setting (look for the “sound wave” or “beaming” icon).
3. Test the leads: Touch the red and black probes together. You should hear a beep or see a reading close to 0.00, indicating a complete circuit.
4. Test the fuse: Place one probe on each end of the fuse.

Good fuse: A reading near zero (or a beep) means the circuit is continuous and the fuse is functional.

Blown fuse: A reading of “O.L.” (Open Loop), a minus symbol, or an infinity symbol (∞) indicates the internal wire has melted and the fuse must be replaced.

A regularly tripping breaker or blown fuse can be caused by a failing part inside the unit, which a professional will need to troubleshoot. Only a licensed HVAC professional or electrician should perform this type of electrical work.

4. CLEAN OR REPLACE THE HVAC FILTER

If your AC is running but not cooling your home effectively or if the airflow is weak, it could be due to the HVAC filter being clogged.

Restricted airflow is one of the main causes of AC issues, and the most common reason is dirty AC filters.

Dirt, dust, and pet dander can build up in filters and obstruct the airflow, reducing system efficiency, raising electric bills, and potentially shortening the unit’s life.

HVAC filters need regular cleaning or changing (every 2-3 months in most Florida homes).

If your home has central air conditioning, like most Florida homes, the AC filter may be located:

Disposable AC filters are freely available in major hardware or home improvement stores. Make sure you get the right size to fit your system.

If your system supports reusable filters, remove the filter and carefully vacuum away dirt, fluff, and dander. Then use a damp rag to wipe off any dust and dirt. Replace the filter once it’s dry.

5. OPEN AND CLEAR THE AIR VENTS

Central air conditioning systems in Florida homes usually use attic-based ducting with a series of air vents in the ceiling or walls to deliver cool air to each part of the home.

Sometimes, vents are closed by homeowners on purpose so that rooms that don’t need cooling don’t receive cooled air. This is based on the mistaken belief that it will save money on electricity.

Closing off rooms will not save energy and closing vents in unused rooms will not lower your electric bill.

In fact, it may cause more harm than good, making the overall system less efficient and causing problems in the ductwork. If air pressure builds up because of closed vents, air leaks, and mold growth can result.

Keep vents and the larger intake grilles open and unobstructed by any furniture or other items, as this can damage cooling efficiency in the home.

6. CHECK FOR WATER LEAKS

If you’re experiencing air conditioning problems, checking for leaks is one of the first AC troubleshooting steps to tick off.

Leaks are sometimes obvious and, at other times, less so.

If water is visibly leaking out of your AC unit, turn the system off and call an HVAC professional to avoid costly water damage to your home. It may just be that the drain line is clogged and backing water up into your home: algae growth in drain lines is arguably the #1 cause of service calls in Florida. 

Try pouring a little white vinegar down the drain line access point every few months to prevent clogs.

Alternatively, ice may have formed around the evaporator coil and started to melt. Again, this problem may need professional AC troubleshooting. First, however, try changing the AC filter to see if that fixes the problem. Most ice buildup issues in air conditioners are due to restricted airflow from clogged filters.

If you suspect a refrigerant leak (refrigerant is odorless but hissing noises are a tell-tale sign), call a professional, as only HVAC technicians should handle AC refrigerant.

7. CLEAR AROUND THE CONDENSER UNIT

Central air conditioning systems use condenser units usually located close to an outside wall of the home.

A durable, weatherproof casing houses the compressor, one of the main system components. Care should be taken to ensure that weeds, plants, shrubs, or mulch (from leaf blowers) don’t get entangled or trapped in the unit and obstruct airflow.

Regularly cut the grass (catching clippings) and prune trees around the unit. Occasionally, spray the outside of the unit or even use a hose with the nozzle aimed at the condenser coil to remove dirt from under the lid and on the coil fins.

Aim for at least two feet of clearance for any large objects around the unit.

AC TROUBLESHOOTING ISSUES THAT NEED AN HVAC PROFESSIONAL

Safety must come first with any AC repairs. Call a licensed HVAC repair professional if you are in any doubt.

The following are some common AC troubleshooting issues that you’ll need a professional for:

Many of the most common air conditioning troubleshooting issues can be averted with a regular AC tune-up, where we thoroughly inspect the system.

One tune-up toward the end of spring and again in the fall is advisable for most SW Florida homes.

SCHEDULE AC TROUBLESHOOTING OR A TUNE-UP IN FORT MYERS

Regular AC maintenance checks help prevent cooling issues, system inefficiencies, and spiraling energy costs.If you’re in SW or Central Florida, troubleshoot your AC problems with the help of One Way Air’s well-established local team of professionals. Contact us today.