What to Check After a Power Outage Before Calling for HVAC Repair

During severe coastal storms in Oregon, high winds can increase the likelihood of power outages. This causes fluctuations in power that can damage your heating, ventilation, and air conditioning (HVAC) system. By preparing in advance and knowing common signs of a problem, you can prevent additional damage.

What Happens to Your HVAC During a Power Outage

As soon as the power goes out, your HVAC system will stop functioning. However, this isn’t what causes the actual damage. When power is restored, the resulting power surge and voltage spikes can harm the sensitive components in your HVAC system.

Once the shutdown occurs, all of the HVAC system’s functions are cut off. The refrigerant that was running through your heat pump or AC lines is still present, but it’s trapped under high pressure. If the power is restored suddenly, it can result in the compressor stalling or overheating. Additionally, the power can end up damaging electrical components, like the thermostat or the control board.

Possible Reasons Why Your HVAC Stopped Working After a Power Outage

If your HVAC system stops working following a power outage, a few different problems may be at fault.

Tripped Breakers

Normally, the breaker panel is set up so that the indoor and outdoor HVAC units are on different breakers that deliver power to your indoor and outdoor units. When both breakers trip, your HVAC won’t get the power it needs to run. If only the outdoor AC unit’s breaker trips, you’ll feel warm air coming from your vents.

You can check for this issue by inspecting the breaker panel and resetting tripped breakers. If the breaker immediately trips again, don’t keep resetting it. Repeated trips indicate an underlying electrical issue that needs to be repaired.

Safety Lockout

Many air conditioners have special safety lockouts that protect the unit from power surges. This lockout keeps the AC from turning on again for 30 minutes after power is restored. By doing so, it can prevent the condenser from restarting too quickly and damaging your AC. Once this lockout is complete, the system should turn on again.

Damaged Capacitor 

Capacitors are responsible for starting up the unit’s compressor. If the power surge causes the capacitor to blow, it won’t be able to start your system. Because of the voltage involved, you should never address this issue on your own. Instead, always schedule professional repairs if you think the capacitor may be at fault.

Thermostat Malfunction

Sensitive electronics like thermostats can become damaged by power fluctuations. The electricity can also scramble your settings, so you may need to reset the thermostat before your HVAC system will switch on again.

Faulty Compressor 

A power surge can sometimes cause the compressor to fail. If this occurs, the compressor won’t be able to circulate refrigerant to cool or heat your home. If a damaged compressor may be involved, you should stop using your unit and book an HVAC inspection.

What To Check When HVAC Stops Working After a Power Outage

Because many modern HVAC systems are designed with blackout protection, the first step after a power outage is to leave the unit alone for 30 minutes. After this time has passed, you can try turning your system back on.

Power outages can cause surges that trip your breakers, damage your thermostat, or trip your disconnect box. Check your breaker panel and disconnect box to see if anything has tripped. Then, you should check your thermostat to see if it is on. Thermostat settings can default to factory settings after an outage, so verify that the settings are correct.

When To Call a Professional

You should reach out to a professional right away if you notice any of the following symptoms after a power outage.

• Burning odors, melted wiring, or other signs of electrical problems
• Signs of a faulty capacitor, such as hard starting and humming noises
• A blank thermostat screen that won’t switch on
• HVAC system that refuses to start
• Repeatedly tripped breakers
• Poor HVAC performance

Concerned about your HVAC system? Reach out to Alpha Heating & Air to schedule your next maintenance appointment.

Frequently Asked Questions

Why won’t my AC turn on after a power outage?

There are a few reasons your AC might not be working after an outage. If the unit has a safety lockout to protect it from power surges, you may have to wait 30 minutes before you can turn it on. As a homeowner, you can also try troubleshooting by resetting a tripped breaker or adjusting your thermostat settings.

Sometims, ACs won’t turn on because of a failed capacitor or faulty compressor. If either of these issues is the cause, you’ll need to schedule HVAC repairs.

How do I safely reset my HVAC system after a blackout?

To reset your HVAC system, turn off your indoor thermostat. Then, shut off the HVAC system at the breaker panel. Afterward, you’ll need to wait 30 minutes for the pressure in the system to balance. Once this time has passed, you can turn on the system at the breaker and thermostat.

What should I check on my thermostat after a power interruption?

After a power outage or disruption, you should check your thermostat display to see if it is working. If the thermostat is blank, you can try resetting the thermostat’s breaker to see if that helps. Thermostats often default to factory settings after a power outage, so check your schedule settings to see if they are still active. You may also need to reconnect the thermostat to the internet.

Can frequent Oregon storms permanently damage my AC?

Absolutely. From November to March, strong winds and heavy rainfall can occur in coastal Oregon. These storms can cause flooding and power surges that damage your HVAC equipment. Additionally, high winds can blow branches and other debris into your outdoor condenser unit.

When is it time to call a professional HVAC technician?

If your HVAC performance drops without a reason, you should reach out for professional help. We also recommend scheduling repairs immediately if you notice burning odors, a lack of airflow, musty odors, repeatedly tripped breakers, or leaking water. Additionally, any HVAC problem that affects your indoor air temperature is an emergency if you have vulnerable family members in your home.