Troubleshooting Your Air Conditioner

Summer comes quickly in Denver.  Days go from needing heat to needing A/C very quickly.  Those first 80 – 90-degree days sneak up, and everyone has the same issues with their air conditioner. Let’s review some common problems that come up. 

Rental Property Air Conditioning Trouble shooting

***Disclaimer:  Please do not turn your air conditioner below 70 degrees.  Creating new cold conditions can cause the air conditioner to freeze up.  If your air conditioner has been continuously running for hours or days and is now not cooling appropriately, please completely turn your unit off, and wait for a few hours before starting it back up.  Your air conditioner may have frozen up and needs time to thaw out to resume standard function.*** 

1.     Will your air conditioner blow air at all?

If you can’t feel the air at all when the A/C is on, and the fan switch is turned on to the “On” position on the thermostat, then let’s go through a few steps first.  If you do feel the air, go ahead and move to step 2 now.

Check the electrical system

  • Let’s start at the beginning of the system.  Check your main breaker box for the breakers titled “furnace” and “A/C.” Your furnace breaker will be a single breaker, and your A/C breaker will be a double breaker (two connected).  Check for the breakers “On” and “Off” directions. Turn both of the breakers entirely off. Flip the breaker to the off position and give each a little push more in the off direction. If they click, they have reset.  Not all breakers do this, so don’t push excessively hard. Go ahead and check and see if this worked. If there is air blowing, the whole issue may have been the power at the panel.

Check the thermostat

  • Now let’s ensure that the thermostat is working correctly.  Set the setting to A/C and turn the temperature at least 10 degrees warmer than it currently is and hit “Hold.”  That should make it so the A/C does not turn itself on and allow us to use the fan switch independently. Turn the fan switch to “Auto” and check one of the vents to see if it is blowing air.  If it is, check the settings to make sure it is correctly set as there should be no air blowing at this time. Now try turning the fan to the “On” position. Go back to the vent and see if there is any air blowing.  If so, go to step 2. If not, continue to next step.

Check the furnace power switch

  • Let’s move on if that did not work, let’s move a little closer to the furnace to try and find the problem.  There is a light switch connected to the stove with typically some metal conduit connecting the wires to the furnace.  They are not always in the same spot so look around (even up). The switch is always located close to the furnace, however.  Flip the switch and take note if the system turned on (remember, the fan switch on the thermostat needs to be turned on for this to work).

Check the furnace doors

  • If that did not work, let’s get even closer to the furnace.  There is a safety switch on one of the doors to the furnace (A/C) fan.  If one of the doors is slightly ajar, it may have tripped the switch and is causing the fan not to turn on.  Remove both doors and reinstall it flush. Once you have done this, go back to step b and see if you can get the fan to turn on.  If you can not get the fan to turn on, give us a call to schedule an HVAC professional.

2.     Check Your Furnace Filter

A dirty filter restricts airflow, and less airflow equates to less cooling.  Remove your air filter and replace if necessary. If your filter is filthy, turn off the system, buy a new one, and then install it.

Replacing the filter should be done approximately every three months, so if you cannot remember the last time you changed your filter, now is probably the time.  Take note of the filter size and purchase the matching size. There are different levels of filters out there, and they vary from $2 to $30, or even more. Top Properties recommends varieties that cost around $10 each.  They seem to be the middle ground that performs well and also clean the air thoroughly. They typically have a better structure overall to better stay in place in the furnace. Changing your filter regularly will help you save money on your power bill as well as giving you fresh, clean, cold air, and protecting the system.

To stay on top of your filters, you can schedule filter delivery regularly at:

(Highly recommended)

3.     Check Exterior Compressor

Exterior compressors for air conditioning

If that did not work, take a look at your exterior air conditioner’s compressor.  It is typically the square box on the exterior of the home that has the big fan on the inside.  With the thermostat’s A/C in the “On” position, go outside and make sure the fan is blowing. Make sure the thermostat is in the on position. If it is and the fan is not running, give us a call to send a professional A/C maintenance specialist to the property.  Modern systems will not turn on for 5 – 10 minutes after it has been shut off, so if you have been playing with the thermostat, turn everything to the off position and come back in 20 minutes.  

Check for cotton (floating tree seeds) on the compressor –

If the fan (from step 1) is working, check the exterior of the unit for cotton.  Many trees in Denver produce those little white fluffies that can build up into a blanket around the air conditioner compressor and can cause it to not cool very effectively.  If you see this blanket around the coil, go ahead and turn the unit off. Turning the unit off will protect the system.

Your next step would be to get a hose and using the highest pressure setting, position the nozzle about 1 to 2 feet away at the top of the unit and start blowing the cotton down the coil.  This motion will take a few times to get right, but getting that blanket of fuzz off the unit will help immensely. Once complete, you can start the unit right away. Let’s see if that works by turning the unit back on. Give it a few minutes, and if the air is coming out cool, then you’re set. If not, then give us a call to schedule some help. 

Dirty half clean and clean air conditioning coil

Additional Tip:  If your home is getting cool only on lower levels, try closing the vents on the downstairs and opening them all upstairs. Cold air enjoys to hang out on lower levels, and to get up to your upstairs can be difficult, especially in older homes.  Magnetic vent covers can even be a great option to make sure as much cold air as possible is reaching the upstairs. Check out Vent Covers on Amazon as one good option.

Also, make sure all vents or air returns are not covered with furniture or blocked by anything on the walls; restricting airflow can cause unbalanced air conditioning and heat. 

Thank you from Top Properties Property Management Denver!