The power was out for five hours in the middle of a summer day. You’ve spent the afternoon trying to keep the kids entertained, the dogs from overheating, and keeping a close eye on your phone’s battery level.
When it finally kicked back on a few minutes ago, everyone cheered, including the dogs. But the house isn’t getting any cooler; in fact, your trusty AC unit is blowing hot air instead. Everyone’s still hot and miserable, you’re ready to pull your hair out, and you have no idea what to do.
Keep reading to learn five possible reasons your unit isn’t turning on, a step-by-step checklist to identify the potential problems, and ways to prevent this headache in the future, plus frequently asked questions that you might not have thought about.
Table of Contents
- 5 Reasons Why Your HVAC May Not Be Turning on After a Power Outage
- Identifying the Problem: A Step-By-Step Checklist
- HVAC Not Cooling After Power Outage: What It Means
- How To Prevent HVAC Problems After a Power Outage
- HVAC Issues After Power Outage: FAQs
- Get Your HVAC Running Again With Fast, Reliable Expert Service From AAA Heating and Cooling
5 Reasons Why Your HVAC May Not Be Turning on After a Power Outage
#1: Tripped Circuit Breaker
A tripped circuit breaker is the most common culprit for HVAC issues after the lights go out and then come back on.
When checking the circuit breaker box, look for switches labeled AC or HVAC. Depending on the type of cooling unit, there could be one or two of them. There is often one for the outside unit and a second for the in-house unit. If either switch is in the middle of the breaker, switch it off and then back on.
If there are any other tripped breakers in the breaker box, you should fix them the same way. There are likely other parts of your house that aren’t working, other than just the AC unit.
If tripped circuit breakers are the problem, then your unit should kick back on shortly afterward.
#2: Blown Fuse
AC unit fuses are sensitive to power fluctuations, so when the power comes back on after an outage, the sudden surge can easily overwhelm the fuse system and blow one. If your unit won’t turn on at all, it’s likely because of a blown fuse or two.
If you suspect the power surge blew a fuse, it’s best not to tinker with it and risk getting hurt. It’s time to call in the big guns, professional HVAC technicians like the ones at AAA Heating and Cooling.
#3: Thermostat Malfunction or Reset
This is another common issue that many homeowners neglect to check when troubleshooting AC units and HVAC systems. Power outages may cause your thermostat to reset to its default settings or quit working entirely. Make sure that it’s set the way you want it, such as turning it to cool and at a temperature lower than the house’s current temperature.
#4: Safety Switch Lockout
A severe jolt or intense power surge caused by the electrical grid rebooting or a lightning strike can trigger your unit’s safety lockout system, which affects your unit’s compressor. After the power returns, if your unit is running but not blowing cold air, or you hear odd noises from the outside unit, your HVAC system will likely require a new compressor.
#5: Damage from Power Surge
Wiring – Burned-out wires can happen, even if the entire system looks fine from the outside; don’t mess with the inside of the unit. Pick a trained professional to do it for you.
Components – Internal parts like the air handler, furnace, and condenser can be damaged from the power returning after the outage
Capacitor – If the unit is making an annoying hum or angry clicking noise, it’s time to call AAA Heating and Cooling.
Identifying the Problem: A Step-by-Step Checklist
- Check your thermostat’s settings.
- Turn the device off and back on again, check and adjust the settings if needed, ensure all the wired connections are attached to the furnace and AC unit, and change the batteries if it uses them.
- Check your circuit breakers.
- Locate the breaker box, open the panel, and look for any switches that are out of alignment with the rest. Flip any improperly aligned switches to the off position and then to the on position.
- Check your furnace.
- Make sure any breakers or switches are turned on at the furnace power supply panel, check the air filter for any clogs or debris buildup, and look to see if the pilot light is on and has a steady flame.
- Check your entire HVAC system.
- Inspect the power switch on the outdoor unit for any damage or wear and ensure it’s switched on. Check the unit’s breaker box for any tripped breakers and reset them. Check the outer casing components for any bulging, oil leakage, or obvious damage.
If none of these steps solves the problem, it’s time to call in the pros.
HVAC Not Cooling After Power Outage: What It Means
If your AC unit is working but is blowing anything that’s not cool air, there are several possible causes:
- Tripped breakers for both indoor and outdoor unit parts
- Thermostat programming reset or complete failure
- Compressor not engaging
- Blown capacitor
- Dirty air filter
- Refrigerant issue
- Safety switch activated to initiate system lockout
This article is for educational purposes only. If you are concerned about your A/C unit, it’s time to call your guys at AAA Heating and Cooling.
How To Prevent HVAC Problems After a Power Outage
Here are several ways to help protect your HVAC system during and after a power outage:
- Install a Whole-Home Surge Protector – This device is installed at your electrical panel to prevent power surge-related problems throughout your entire house.
- Use a Dedicated HVAC Surge Protector – This is a high-voltage surge protector that is only used for your HVAC system, which will reduce the likelihood of your entire system being affected by another power outage.
- Schedule Regular Maintenance – Routine tune-ups will help keep your unit in tip-top shape and give your HVAC tech plenty of time to warn you of any issues, especially if your system is hit with another power outage.
- Replace Air Filters Regularly – Make sure there are no clogs and that the intake is free of debris, which can prevent the necessary level of air flow the unit needs to start up again after a power failure.
HVAC Issues After Power Outage: FAQs
How Do I Reset My AC After a Power Outage?
- Turn the thermostat off.
- Shut off the AC unit breakers.
- Wait 30 minutes.
- Turn breakers back on.
- Set the thermostat to cool.
- Lower the temperature and wait for the system to start.
If your system doesn’t reset, you’ll have to do some troubleshooting to figure out why and what you should do to fix the problem or call for backup.
Why Is My AC Not Working After the Power Goes Out?
A power outage is often followed by a major power surge when the electricity is restored. This could cause several different problems that would cause your air conditioner to stop working, such as:
- Tripped circuit breaker
- Blown fuse
- Safety switch lockout
- Thermostat stuck/reset
- Damage from a power surge
If you aren’t sure what the problem is, call the team at AAA for help!
Can a Power Outage Damage HVAC?
A power outage can fry your HVAC system’s electrical wiring, interior unit components, and the main essential parts, like the capacitor and compressor. If any of these parts are damaged, it could cause serious malfunctions in your HVAC system that might require the help of a professional. If you’re not sure what to do, it’s best to call a licensed, certified HVAC company that can diagnose and repair the true problems without causing further damage to your home’s electrical system.
When Do I Know It’s Time To Call an HVAC Professional?
The most obvious time to call is when you don’t feel comfortable doing any of the troubleshooting work at all. If your AC system is on the fritz, you’ll need to contact an HVAC team.
Get Your HVAC Running Again With Fast, Reliable Expert Service From AAA Heating and Cooling
If you’ve tried all the tips suggested in this article to no avail, it’s best to reach out to a pro, because it’s likely that the issue is one a homeowner shouldn’t fix on their own.
If your HVAC system won’t kick back on after a power outage, give your friendly neighborhood Portland HVAC company, AAA Heating and Cooling, a shout at (503) 284-2173. We want you wrapped in a hoodie in July, which means getting your AC up and running as quickly as possible after a power outage.
If the power outage damaged your furnace or other type of heating system, we can solve those problems as well. Contact us to set up an appointment today.