Based on the most common issues
The success of any repair begins with accurate diagnostics and the proper tools. Air conditioners are more complex than many people realize. However, in this guide, we discuss some basic tasks that the general public and DIYers can handle on their own
When it comes to diagnosing issues with your air conditioning system, one of the first places to check is the thermostat. Thermostats vary widely, from simple models that only regulate temperature and fan settings to more advanced programmable versions. These modern thermostats can adjust temperatures throughout the day for optimal comfort when you're at home and enhanced energy efficiency when you're away or asleep. Wi-Fi enabled thermostats even allow you to control your home's climate remotely via a smartphone or computer.
With all these options, thermostat settings can sometimes be the reason your air conditioner doesn't seem to be working properly. If you're noticing any of the following symptoms, it may be a thermostat issue:
If any of these issues sound familiar, before reaching out to an HVAC professional, take a moment to check the thermostat. Here are a few steps to troubleshoot the problem:
Is the thermostat set to heat instead of cool? If so, simply switch the mode to "cool" or set it to "auto" so the system can automatically adjust between heating and cooling as necessary.
The fan setting on your thermostat is important. If it’s set to "on," the fan will continue running even when the air conditioner isn't actively cooling the air, which may result in warmer air blowing from the vents. Switching the fan setting to "auto" will ensure the fan only operates when cooling is required. If the fan is set to "off," simply switch it to either "on" or "auto."
IDouble-check the temperature to ensure it hasn't been changed by someone else in the household. A higher temperature setting could be preventing the system from cooling effectively.
For those with programmable thermostats, it's worth reviewing your “comfort schedule” to ensure that the set times and temperatures are still in line with your routines. Check that the settings align with when you're at home, away, and asleep.
If, after making these adjustments, the issue persists, it may be time to call in a professional HVAC technician for further inspection and repair.
A common issue when troubleshooting an air conditioning system is a dirty air filter. It’s important to remember that your AC system is not just the outdoor unit you see outside your home. Systems also have an indoor air handler, which could be a furnace or fan coil. This indoor unit typically includes an air filter designed to catch dust, dirt, and other particles from the air. Whatever the size and brand of the filter, regular maintenance is essential for effective air filtration and proper cooling.
Neglecting maintenance can lead to a clogged filter, which restricts airflow. This can result in decreased efficiency, discomfort, or even cause system failure in some cases.
Signs that your air filter might need attention include:
Before inspecting the air filter, ensure your thermostat is set to cooling mode and that the temperature setting is accurate. If the issue seems to be a dirty filter, refer to your owner’s manual for instructions on how to remove, clean, or replace it. You can also check out our guide on how to change air conditioner filters.
For most systems, the basic filter is located inside or near the furnace cabinet or the return air duct.
If cleaning or replacing the filter doesn’t resolve the issue, it’s a good idea to reach out to your local HVAC professional for further help.
If your air conditioning system isn’t running and there is no airflow from the registers, it’s possible that the power supply to the system has been interrupted. Since your air conditioner operates on electricity, the first thing to check is your home’s electrical panel (breaker box). Look for any blown fuses or tripped circuit breakers that may have caused the loss of power.
Your air conditioner’s outdoor unit is typically connected to a dedicated 220-volt circuit breaker and a safety disconnect, usually located near the unit itself. In addition, it will also be linked to a circuit breaker or fuse in the main electrical panel.
Your air conditioner’s air handler unit is typically connected to a dedicated breaker and a safety disconnect, usually located near the unit itself. This could be 220V or 125V.
It’s important to remember that working with electricity can be hazardous. If you identify a blown fuse or tripped breaker, only proceed if you are confident in your ability to safely reset the breaker or replace the fuse.
If you're unsure or uncomfortable handling electrical components, consult a qualified professional. Repeated tripping of the circuit breaker or blown fuses may indicate a deeper issue, such as a short. In this case, contact a technician experienced in diagnosing air conditioning electrical problems.
For most systems, the basic filter is located inside or near the furnace cabinet or the return air duct.
The condensing unit of a typical split-system central air conditioner is located outside your home and comprises several key components: the outdoor coil, compressor, condenser fan, and electronic controls. If you're experiencing any of the following issues, it may indicate a problem with the condensing unit:
Similar to issues with the evaporator coil, a malfunctioning condensing unit may have a dirty coil or a refrigerant leak. Other potential problems could involve a damaged compressor, a failing condenser fan motor, or an issue with the run capacitor. These types of problems generally require professional attention. It's important not to attempt troubleshooting refrigerant or electrical components on your own.
If you're experiencing any of these symptoms, it's advisable to consult with a qualified technician to avoid further damage and ensure your air conditioner operates safely and efficiently.
In a typical split-system central air conditioner, the evaporator coil is usually located indoors, either in the home or in the garage, as part of the air handler unit. If your system includes a furnace, the evaporator coil is generally placed where the outgoing air flows. In systems with a fan coil, the evaporator coil is typically housed inside the fan coil cabinet.
If you suspect your evaporator coil may be frozen, look out for the following signs:
Several factors can lead to a frozen evaporator coil, including:
It is important to avoid running your system with a frozen evaporator coil, as doing so can cause severe damage to the coil and lead to costly repairs. Since the evaporator coil is typically not easy to access and refrigerant troubleshooting should be handled by a professional, it’s best to turn off the system immediately and contact your local service provider. Do not attempt to address refrigerant or electrical issues on your own.
