What checklist for a Broken HVAC System Can I Use?

The middle of a hot summer, or no matter where your company is located in the world where the climate includes extremely high temperatures is the worst time to find out your HVAC system won’t turn on. 

Your first reaction may be to call a local HVAC repair company to come out and get your broken AC unit fixed right away. However, you may want to take a moment before calling in order to check a few things yourself. There are several possible problems that could cause your HVAC to not turn on. Many of these issues are easy to spot and doing so may save you money.

Should you immediately call an HVAC technician when your AC won’t turn on?

Not right away. According to HVAC experts and their in field experience who have dealt with a variety of issues that can stop an air conditioner from working and have seen it all advise not to call anyone yet. 

While a lot of problems require a skilled technician to identify and remedy, some of the issues that may be causing your HVAC to not turn on can be detected by you or your inhouse technical staff themselves. HVAC service technicians often get called out for problems that end up being simple and easy tasks that the on site technicians are likely able to handle on their own.

It seems normally most HVAC repair companies will be happy to come out and address whatever AC problem you are having, they want you to be informed about some of the simple problems that may not require an HVAC technician to fix. Plus, they don’t want you to have to spend money when you don’t have to. Because handling a simple air conditioning fix on your own will save you time and money, they have created this checklist of potential problems you can look for when you first notice that your air conditioner is not turning on.

Broken Air Conditioner Checklist

These are the steps to run through first when your HVAC system unit(s) doesn’t turn on. Some of these items are simple and can be done by yourself in a matter of minutes.

  • Check your air filters. Has it been awhile since you’ve replaced them? A very dirty filter could be what’s leaving you to believe your HVAC is broken.

Is it dirty and needs to be replaced?

Clean air filters allow for proper airflow. When it’s clogged with dust and debris, the airflow is obstructed. Each company’s needs are different so changing your filter only one time every few months may not be enough.

  • Check the thermostat

Is your thermostat set to COOL?

 Have you set the temperature to be at least 5 degrees below the current ambient temperature?

 Is it not on because the batteries are dead?

This is an easy fix. While each thermostat is unique, you may find a spot along the edge of your thermostat with the word PRESS. Simply press that area to remove the battery compartment and replace the batteries. Other thermostats require you pull off the cover of the wall thermostat unit.

  • Check the power and power supply.

  Have you accidentally tripped the circuit breaker?

how to reset a circuit breaker
  • Check the inside AC unit power switch. Look for a switch that looks like a light switch that controls the HVAC units, possibly near your furnace.

Is this inside the unit switch in the on position?

If it was accidentally turned off, the blower would be turned off which may have caused the inside unit to freeze, causing your entire air conditioning system to shut down.

  • Check if your outside unit is frozen, or obstructed.

Is there ice covering your air conditioner, or debris blocking the intakes?

If so, turn your unit off and turn the fan on. Allow it time to defrost – DO NOT try to speed up the process by using heat or trying to scrape the ice off. Then clean away any visible dirt on the filters or replace them entirely. This may get your AC up and running right away, but you should call an HVAC technician to come out and inspect the unit. A frozen air conditioner could mean you have a refrigerant leak, which can be dangerous for you and your staff.

  • Check to see if your AC units are very dirty.

Are your air conditioner coils covered in cottonwood seeds, pollen or other debris?

Dirty and clean AC coils

If so, you need to clean them. Every environment is different, however a lot of areas face the problem of falling debris from trees bushes etc. These natural conditions during different seasons can really clog up outside HVAC conditioning unit coils. To clean your AC units, turn them off at the outside Service Disconnect panel, remove the tops and any outer caging, and take out the fans. Take a garden hose and spray from the inside out all around the inside of the units. Then you can spray down the exterior of the units.

  • Check your AC unit’s fan.

Is your HVAC running but your fan is completely still?

If so, either the fan motor or the capacitor is bad. While this may be something you will want a heating and air professional to handle, there is something you can do to get the temperature back down in your building immediately. With a crowbar or some other long instrument, reach in to the top of the AC unit to try to spin the fan blades counter-clockwise. This may get your fan spinning, at least temporarily. Because the problem likely lies with your capacitor, your AC’s fan will again stop spinning. But getting your air conditioner’s fan to start up yourself will mean your building should start cooling back down while you wait for an HVAC technician to arrive.

  • Check the condensate drain line. This is the line that drains the water that created by condensation from your HVAC unit to outside your building.

  Do you have a clog in the condensate line?

If so, it could have tripped a safety switch that shut down your HVAC. You can try unclogging this line by using a wet/dry vacuum to suction the blockage out. You can always call your local

HVAC repair company to come out and clear out whatever is blocking your AC condensate drain line as well.

  • Check the age of your AC system.

  Have you refurbished your office, or facilites in the last few years?

If so, your HVAC units might not be able to keep up. Your cooling system may not be able to handle the extra square footage that has been added or to a change in airflow that a large remodeling project may have caused.

  •  Are your HVAC units very old?

If your air conditioners are more than 10 years old, it may be time to consider replacing them with a model that is suitable to your building’s size and your additional staff’s comfort needs. This is a great opportunity to make sure you are purchasing an HVAC system with a high SEER rating which can save you thousands of dollars on your energy costs every year.


The information and list of above regarding your broken HVAC cooling should help you to determine these types of issues and hopefully help save you time in money in the short term, but also prevent further catastrophic and expensive failures of your system in the long term.  


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  2. This blog is appreciated by me because there are so many people here who can help with how to troubleshoot HVAC. Thanks for this blog which is very much help.

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