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What to Do When Your Air Conditioner Won't Turn Off?

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Summers in Oregon are mostly warm and rarely scorching. However, Portland, Oregon residents have increasingly experienced grueling heat waves, especially in the past two decades.

Heatwaves in Portland have increased average daytime and nighttime temperatures. Since temperatures typically rise to 83°F during Portland’s hottest months in July and August, more homeowners see the need to install efficient and energy-saving air conditioners.

Additionally, many residents in Portland, OR report complications with their AC system and a common problem is systems that fail to turn off. Air conditioners that won’t turn off result in higher electrical bills. On top of that, an air conditioner that runs for hours on end will have its components wear out faster.

Air conditioning systems that keep running are mainly caused by malfunctioning components or dirty parts that reduce cooling and ventilation. Wrong-sized AC systems and extreme weather conditions also cause this AC issue.

If your air conditioner won’t turn off, you should first check your AC settings. Make sure to clean the condenser coils, air filters, and evaporator coils to enhance cooling and airflow.

If none of these solutions work, call a local HVAC professional in Portland, OR to check on your system. Possible maintenance options include AC repair or replacement depending on your household needs, room layout, and weather conditions.

Air Conditioning in Portland, Oregon

Summer in Portland, Oregon starts in July and ends in September, occasionally extending to early October. The hottest episodes last from mid-July until August, when daily average temperatures range between 78°F to 84°F.

While Portland generally has short and warm summers, there have been more unbearable heatwaves in the past 20 years. Occasionally, temperatures do go over 100°F. In fact, on June 27, 2021, Portland reported its highest temperature ever at 116 °F since the National Weather Service started recording in 1940.

Because of this, it’s important to invest in a reliable and efficient HVAC system to ensure energy savings. A well-maintained air conditioning system will also help you achieve a more comfortable household during the summer months.

In the next section, figure out how to do air conditioning maintenance if your system won’t turn off.

Air Conditioner Routine Maintenance in Portland, OR

As mentioned, routine HVAC maintenance will ensure that your AC is running efficiently, which means you’ll get lower electricity bills monthly.

Your HVAC system will also last longer since the parts won’t wear down from running for hours. A well-maintained air conditioner can last you 10 to 15 years, and in some cases, 20 years.

With routine maintenance, you can avoid paying for costly repair services with an HVAC provider several times throughout the year.

Routine air conditioning maintenance will also protect your belongings. High heat and humidity can destroy your furniture, especially if it’s made with wood.

Preventive HVAC maintenance is critical to preparing your AC system for the hottest months of the year. Ideally, you should hire an HVAC professional in the spring before extreme weather ruins your AC.

Why won’t my AC turn off?

There are various reasons why your AC won’t turn off.

There might be a problem with one or two of the components, or the unit might just need a bit of cleaning. In these scenarios, you can try to do repairs and cleaning by yourself or have a professional do it.

Another possible reason why your air conditioner keeps running is that it can’t keep up with your desired room temperature. Your AC system might be too small or your area’s weather and temperature could be too extreme for your AC. In this case, you’ll need to get an air conditioner replacement.

Here are the most common reasons why your AC won’t turn off. Each situation will entail different troubleshooting methods:

Blower fan

If your AC won’t turn off, the first step to troubleshooting the unit is to check the fan settings.

Most homeowners have their AC’s fan settings on Auto. This means that the fan will only run according to the unit’s cooling cycle.

When your fan settings are set to Auto, the fan will turn off when the current room temperature reaches your desired room temperature. However, if your fan setting is set to “ON”, the fan will keep running regardless of the room’s temperature.

Set your AC fan settings to Auto and test to see if your AC will keep running. If your air conditioner still won’t turn off even after reaching the set room temperature, there is most likely a problem with the thermostat.

Dirty Evaporator coils and condenser coils

Dirt, dust, debris, and mold can accumulate in your air conditioner’s evaporator coils. Dirty evaporator coils make the cooling cycle inefficient. The system will keep blowing warm air throughout the room.

Cleaning evaporator coils requires technical skills, so if you’re unfamiliar with AC parts and maintenance, make sure to call an AC service provider.

However, if you’re confident with your HVAC cleaning skills, follow these steps:

  1. Switch off the air conditioner and remove it from the power outlet.
  2. Open the AC compartment using a screwdriver and locate the evaporator coils.
  3. Use a spray bottle to apply commercial cleaner or a solution of water and a cleaning detergent to the coils. Let the detergent sit on the coils for 10 to 15 minutes.
  4. Gently wipe away the dirt and debris with a sponge or soft cloth.
  5. Replace the casing and secure using the screwdriver.

Extreme weather and temperatures

Even though your air conditioner is in tip-top shape, extreme weather conditions can cause your AC system to malfunction. Your AC will continue running for hours until it reaches your programmed temperature.

To check if extreme weather is the culprit of your AC issue, check if the system shuts down as normal during the cool periods of the day.

For many households, their AC unit may not be equipped with the demands of rising average temperatures. Since more heatwaves are occurring in Portland, Oregon, it will be a smart move to consult with a local HVAC technician to inspect your current AC system.

An experienced local HVAC contractor will consider the area’s average high temperature and heat waves when recommending the appropriate AC system for your house.

AC Size

Each cooling cycle lasts between 20 to 30 minutes. When your current room temperature starts to rise, your AC unit will begin another cooling cycle.

If your air conditioner is too small, the unit will run the cooling cycle for prolonged periods of time. This means that the system is working extra hard to reach your programmed room temperature, resulting in higher electrical bills.

When choosing an air conditioner, you need to consider your home’s square footage to calculate the appropriate BTU capacity for your AC. An experienced HVAC contractor will also consider the following factors:

  • Type of insulation
  • Construction materials
  • Ceiling height
  • How many windows
  • Available sunlight
  • Number of household members

Make sure to call an air conditioning professional to evaluate the appropriate AC size for your home.

Air Conditioner Repair and Replacement

If your air conditioner has faulty components, it’s likely that it will keep running for hours without cooling your home properly.

Since the Portland area’s been experiencing hotter climates year after year, it’s inevitable that you’ll need to call in regular AC repairs.

For air conditioners to become energy-efficient, you will need to order a replacement unit every decade, especially if you notice that your repair needs are becoming more regular.

Whether it’s AC repairs or replacement that you need, make sure to call a trusted local HVAC service in Portland, Oregon.

Need help with your Air Conditioner? Call us today for your AC Repair needs

If you notice that your air conditioner’s fan or cooling system keeps running throughout the day, you need to get your HVAC system serviced.

Well-maintained air conditioners have cooling cycles lasting between 20 to 30 minutes. If the unit has malfunctioning or dirty components, it’s likely that the cooling cycle will last longer, resulting in higher bills and faster system degradation.

To avoid costly AC repairs, make sure to do routine maintenance by hiring an HVAC expert at least once a year. Professionals will be able to evaluate the condition of your HVAC system so that it stays efficient.

If you’re in need of air conditioning services in Portland, OR, get in touch with us at Sunset Heating & Cooling.

Our company has been helping Portland residents with their HVAC needs since 1922. We have steadily expanded our customer care to surrounding areas in Oregon.

We are also proud to share that we received an A+ rating from the Better Business Bureau for our customer service and dependable workmanship.

Our air conditioning services include:

  • AC repair and maintenance for unusual noises, leaks, excess moisture, warm air, and uneven cooling
  • Air conditioning replacement and installation


At Sunset Heating & Cooling, we offer a flat-rate pricing system and financing options so that you don’t have to worry about overspending on your projects.

To book our services, get in touch with us at (503) 500-5866. You can also book our cooling, heating, and electrical services online.

What Our Clients Say

Sunset went out of their way to help with my project and David was amazing. Great job and look forward to future projects.

-Todd T.

Roman did an awesome job. I had the trifecta, new AC unit ,furnace and hot water heater. Courteous, and competent service. I highly recommend Sunset Heating & Cooling.

-Charles E.

Eduardo provided excellent service when he repaired our AC. I felt his effort was over and above expected. Polite and professional at all times. Good job!

-William G.

Caring, professional and helpful. Thanks for making things happen quickly and getting my Dear friend's heating back up and running in such a quick manner. You went above and beyond for a family in need and that is very much appreciated. Thanks from the whole group!

-Kristina K.

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