How to Fix your Own Air Conditioner

Did you know that minor air conditioner repair can cost from $80 to $100? And by minor, we mean repairs that you could actually do yourself. So to prevent you from paying a HVAC technician for repairs that you could actually do, here are some common problems and the simple steps that you can do to have your cooling unit working again:

Indoor fan is not running. First thing to check is the thermostat. Make sure it’s receiving power. You’ll know that the digital thermostat has no power if it’s blank. If it’s blank or if it has batteries, go to the fan coil or the furnace and unplug it. Plug it back in after a few minutes. This will reset the system and should cool again. If the unit’s a fan coil which might be hard wired, you can simply trip the circuit breaker or you can also pull the disconnect’s handle to the off and turn it back to its ON position.

Indoor unit is leaking water. Check the drain pan at the bottom the cooling coil. If it’s full of water, then the power may have been cut off by the overflow switch to prevent your house from being damaged by the water.

To solve this, unplug the white plastic pipe or the emergency drain line which runs by the side of your house, outside. There are units that do not have overflow switches, so if your unit doesn’t have one, here’s the next step:

Unplug your furnace and have a lamp plugged into the same socket. Remember that this will not work if what you have is a fan coil since circuit is 230 volts which is high voltage. Only a professional should check the socket using a volt meter. If the lamp won’t turn on, then there is no power to your indoor unit. In this case, you will have to check the circuit breaker and trip it until the lamp lights up. If it turns on, then the problem is fixed. You can plug the furnace back in and you can then set the desired temperature on the thermostat. Note that due to internal time delays, the thermostat may take 4-5 minutes to call for cooling. The thermostat should also have a green light on or it should display the word cooling once it calls for cooling. If the air conditioner doesn’t come on, turn the fan switch on to see if the fan will run.

Indoor fan is running but there is no air flowing from the air registers. If the fan comes on but there’s still no cooling, check the supply air register for air flow. If there’s no air flow, the filter may be clogged. Take the filter out, unplug the fan coil or the furnace, plug it back in after a few minutes, and restart the system. If there’s still no air flow, then your coil may be iced up. Let the ice melt into your drain pan for several hours because having the fan run continuously will defrost the coil, then start the system again. Note that the thermostat should not be calling for cooling if the fan is running.

The fan is running; there is no air flow in the supply registers, but there’s good air flow in the return air grills. Have a notebook paper placed flat against your supply air registers. This will check the air flow at the return air grills. If the paper stays and sticks flat, then there is airflow. If there’s no airflow, then one of the ducts in the attic, crawl space or wall has come loose from the fitting. There may also be a hole in the ductwork. Place the duct back over the fitting and use a duct tape to tape it securely. You can also use the duct tape to patch the holes in the duct. If you have metal ductwork, it might’ve come loose, too. You can still use the duct tape it to reconnect the ductwork.

There is good airflow but it’s not cold. If the fan runs, the thermostat calls for cooling and there is air flowing out of the vents but there’s no cooling, you will need to check the outdoor unit. Make sure the compressor and the condenser fan are running. If you can hear the compressor but the condenser isn’t running, keep your compressor from being damaged by turning the unit off right away. Once it’s off, try using a stick to give the blade of the fan a push. If it moves easily, the condenser fan motor may be burned out. However, if the fan blade is very difficult to move, the bearing may be bad and in this case, spray WD40 on the bearing as it will get the unit running shortly until you have a technician who will have the fan motor replaced. Also, the fan blade should not be scraping onto something. If it does, simply bend the blade until it does not scrape again.

If both the compressor and condenser do not work and there’s no sound at all, check if you have a blown fuse or a tripped circuit breaker. For blown fuse, simply replace them and if it’s a tripped circuit breaker, simply flip it back and forth.

Condenser runs for a few minutes but stops even before it has cooled your home. If the condensing unit still does not run after checking the circuit breaker and the fuses, then you may have high pressure limit which is usually caused by a clogged or a dirty condenser coil. For this, you can turn the unit off, clean the condenser coil with a broom, and then wash it with a water hose. This will also lower the temperature of the coil. Once it’s done, turn the unit on, turn the thermostat off and then turn it back to cooling. The unit should start working normally again.

If none of these steps work, then you will need to have a technician over as it may already be a problem with the control circuit board, refrigerant, capacitors, or compressor. Be sure to have a qualified technician do the work for you.

One thing to do to prevent future problems is to install a programmable thermostat as it can monitor your heating and air conditioning equipment and make sure that it’s running efficiently.