What To Do If an HVAC System Won’t Turn On

If your air conditioner is iced over or obstructed by debris, turn it off and switch on the fan to defrost naturally. Clean or replace dirty filters to possibly restore functionality. Contact an HVAC technician to inspect for potential refrigerant leaks, which could be hazardous.

The middle of a hot summer is the worst time to discover an HVAC system that won't turn on. The first reaction may be to call a local HVAC repair company to fix the broken AC unit immediately. However, take a moment to check a few things first. Several possible problems could cause the HVAC system not to turn on. Many of these issues are easy to spot, and addressing them may save money.

Should an HVAC Technician Be Called Immediately When the AC Won't Turn On?

Not right away. According to HVAC experts with extensive field experience, it is advisable not to call anyone yet. While many problems require a skilled technician to identify and remedy, some issues that may be causing the HVAC system not to turn on can be detected by in-house technical staff. HVAC service technicians often get called out for problems that turn out to be simple tasks that on-site technicians can handle independently.

HVAC repair companies are typically happy to address any AC problem but want clients to be informed about some simple problems that may not require an HVAC technician to fix. Handling a simple air conditioning fix oneself will save time and money. Here is a checklist of potential problems to look for when the air conditioner is not turning on.

Broken Air Conditioner Checklist

These are the steps to run through first when the HVAC system unit doesn't turn on. Some of these items are simple and can be done in a matter of minutes.

Check the air filters

Has it been a while since they were replaced? A very dirty filter could lead to the belief that the HVAC is broken.

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

Check the thermostat

Is the thermostat set to COOL?

Is the temperature set at least 5 degrees below the current ambient temperature?

Is it off because the batteries are dead?

While each thermostat is unique, look for a spot along the edge of the thermostat with the word PRESS to remove the battery compartment and replace the batteries. Other thermostats require pulling off the cover of the wall thermostat unit.

Check the power and power supply

Has the circuit breaker been accidentally tripped? Check the power switch inside the AC unit. Look for a switch that looks like a light switch controlling the HVAC units, possibly near the furnace. If it was accidentally turned off, the blower would be turned off, which may have caused the inside unit to freeze, causing the entire air conditioning system to shut down.

Check if the outside unit is frozen or obstructed

Is there ice covering the air conditioner, or is debris blocking the intakes? If so, turn the unit off and turn the fan on. Allow it time to defrost. Don't try to speed up the process by using heat or scraping the ice off. Then, clean away any visible dirt on the filters or replace them entirely. This may get the AC up and running right away, but call an HVAC technician to inspect the unit. A frozen air conditioner could mean a refrigerant leak, which can be dangerous for staff.

Check if the AC units are very dirty

Are the air conditioner coils covered in cottonwood seeds, pollen, or other debris? If so, they need cleaning. Each environment is different, but many areas face the problem of falling debris from trees and bushes. These natural conditions during different seasons can really clog up outside HVAC conditioning unit coils. To clean the AC units, turn them off at the outside service disconnect panel, remove the tops and any outer caging, and take out the fans. Use a garden hose to spray from the inside out all around the inside of the units. Then, spray down the exterior of the units.

Check the AC unit's fan

Is the HVAC running while the fan is completely still? If so, either the fan motor or the capacitor is bad. While this may be something for a heating and air professional to handle, there is something that can be done to get the temperature back down in the building immediately. With a crowbar or some other long instrument, reach into the top of the AC unit to try to spin the fan blades counterclockwise. This may get the fan spinning, at least temporarily. Because the problem likely lies with the capacitor, the AC's fan will again stop spinning. But getting the air conditioner's fan to start up will mean the building should start cooling back down while waiting for an HVAC technician to arrive.

Check the condensate drain line

This is the line that drains the water created by condensation from the HVAC unit to the outside of the building.

Is there a clog in the condensate line? If so, it could have tripped a safety switch that shut down the HVAC. Try unclogging this line by using a wet/dry vacuum to suction the blockage out. A local HVAC repair company can also be called to clear out whatever is blocking the AC condensate drain line.

Check the age of the AC system

Have the office or facilities been refurbished in the last few years? If so, the HVAC units might not be able to keep up. The cooling system may not be able to handle the extra square footage that has been added or the change in airflow that a large remodeling project may have caused.

Are the HVAC units very old? If the air conditioners are more than 10 years old, it may be time to consider replacing them with a model suitable for the building's size and the staff's comfort needs. This is a great opportunity to make sure an HVAC system with a high SEER rating is purchased, which can save thousands of dollars on energy costs every year.

Conclusion

The information and list above regarding a broken HVAC cooling system should help determine these types of issues and hopefully help save time and money in the short term while also preventing further catastrophic and expensive failures of the system in the long term.

Fix My Air DFW of Fort Worth specializes in residential and commercial HVAC services, including routine maintenance, installation, and repair. All makes/models. Call us at (817)839-3511.