Air Conditioner Troubleshooting: Fixing the Most Common Problems

Published by 
AllThingsHVAC
Last updated: 
June 5, 2018

There is nothing more annoying than your air conditioner failing to work in the middle of a heat spell. In such circumstances, you may have to wait for days before an HVAC technician can repair your unit. In most cases, air conditioners repairs should be handled by HVAC technicians, but there are simple repairs you can do yourself with a little air conditioner troubleshooting. This guide will explore some of the most prevalent problems and how to fix them.

air conditioner troubleshooting

Tools for the Job

Apart from parts that you may need to buy depending on the nature of repair required, you also need to have working tools. Here are most of the tools that you need to complete your DIY project.

  • Cordless drill or driver.
  • Nut driver.
  • Adjustable wrench.
  • Voltage tester.
  • At least 2 insulated screwdrivers.
  • Pliers- Needle-nose.
  • Socket set.
  • Multimeter.

You may also require some materials before you initiate air conditioner troubleshooting. This will eliminate unnecessary last-minute trips to stores. Here is the list of the main materials:

  • Fuses.
  • Capacitor.
  • Contractor.
  • Compressed air.
  • Condenser fan motor.

Air Conditioning Problems

Your AC Unit Won’t Turn On

If your air conditioning system fails to start, there could be a range of potential causes that you need to check out. First, check if the condenser is running, then confirm if the thermostat is set properly and make sure the AC is plugged in. One of the challenges could be the setting on the thermostat. You can start air conditioner troubleshooting by lowering the thermostat to 5 - 10 degrees and observe if the unit will work.

Another potential problem could be the fuse. Check if the fuse is blown. If not, then check if tripped circuit breaker or loose wiring is the problem. To test the fuse, you need to set your multimeter to a lower Ohms scale then place the black and red leads on the opposite ends of the fuse. Zero, infinity symbol, or minus reading indicates a blown fuse. A blown fuse could also be a sign of failure in the condensing unit.

You may also need to inspect internal part of the access panel. The best way is to follow the electrical conduit to find the access panel. After putting the power off, you need to check if the electrical wires and connectors are intact. If there is any chewed insulation, fix them if you are comfortable with electrical repairs, otherwise, engage a professional. Besides this, you may need to replace the capacitor and contactor. These items can degrade with time.

If you replace the fuse and it blows up again, or if the unit won’t turn on after you have done the above replacements, or if the coil is frozen, the problem could be the compressor or motor. At this point, it is best to contact your HVAC professional to fix the problem.

Your AC Unit Is not Cooling Air or Isn’t Working Optimally

Even if the thermostat settings are correct, your AC system may still fail to work. A potential problem could be the system has a blocked air condenser, or it is dirty. The first step is to make sure all the register are wide open and the furnace filter is clean. You can then clean the unit from outside to remove any weeds or debris that may be blocking the free flow of air.

You also need to check the filter. Oftentimes, the filter may accumulate a lot of dirt, which may prevent the flow of air to the evaporator coil. So, as you carry out your air conditioner troubleshooting, you can test if your filter is working by seeing through it.

You should change your filters at least once a month if you are constantly using your AC unit or if you have pets. If the filter is working, and your AC still fails to work, then the problem could be linked to the refrigerant or compressor.

Leaking Refrigerant

One of the problems that you will deal with in your air conditioner troubleshooting is refrigerant leaks. If your AC unit is low on refrigerant then there are two potential dangers. The unit might be undercharged at installation or the refrigerant is leaking. The refrigerant is the fluid mixture that keeps everything cold.

To fix refrigerant leaks, you will need a trained technician. These leaks can be harmful to the environment. According to Energy Saver, your air conditioner functions optimally when the refrigerant is charged according to manufacturer's specifications.

Leaking Ducts

Another potential culprit that may prevent your AC unit from working is leaking or dirty ducts. If you are getting warmer air than you expect, then there could be a problem with ducts. Generally, the central air conditioning system is well sealed, however, the ductworks that run through the ceilings and walls could develop leaks due to poor workmanship or rodents. If there are leaks in the ducts, the cool air will escape before reaching your room. Part of the air conditioner troubleshooting could also involve checking the window seals around the AC system to ensure hot air is not getting in.

Besides checking for leaks, you should also need to regularly clean your AC unit, for instance, replacing filters on a monthly basis, cleaning the condenser and evaporator coils, and clearing the drain lines at least two times a year.

Caution Notes

Before you start fixing anything on your air condition system, ensure you have turned off the power. Turn off the power at the breaker box inside then do the same to the exterior shut-off box close to the exterior condenser. If you are not sure about a specific situation, especially the ones that touch on the electrical and the core of the system, please involve a professional.

Wrapping Up

If there's one thing that you need to remember from this discussion on air conditioner troubleshooting is to have a routine maintenance plan. Even if the above troubleshooting doesn’t work, at least you already covered most common problems. So, your HVAC professional can focus only on the elusive challenges. Moreover, when you fit new parts on your AC unit, you are extending their lifespan as well as reducing chances of breaking down. If you have successfully completed DIY AC repair recently, we will be happy to hear about your experience in the comment section below.

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