How Do I Get My Furnace Fan To Run Continuously? Quick Help

Understanding the Fan and Furnace System

When it comes to fan and furnace systems, getting the fan to run continuously can be key. Here’s what you need to know:

Heating CycleCooling Cycle
Fan runs when heat is neededFan runs when cool air is needed
Limit switch turns fan on/off based on temp settingsSummer switch to override limit switch in summer
Thermostat set to “auto” not “on”Check for shorted wire or blower motor issue

Not always necessary to run fan continuously. For example, no cold spots or poor circulation. Then, let the furnace system operate as intended. However, if need a fan to run continuously, check thermostat settings, use manual overrides.

Did you know that more than half of all HVAC service calls are related to fan and burner issues? Address these problems quickly for a comfortable and energy-efficient home. By understanding your fan and furnace system, you can troubleshoot common issues. And, save money on repair services.

I’m no HVAC pro, but I do know how to troubleshoot a fan limit switch.

How Do I Get My Furnace Fan To Run Continuously

Image of a fan of a furnace

Troubleshooting the Fan Limit Switch

Troubleshooting the operation of the furnace fan is crucial during summer periods as the fan acts as a circulation system for cool air in the house. 

The fan limit switch, which controls the operation of the fan, can malfunction, leading to various issues. 

Below is a 4-step guide to troubleshooting the fan limit switch in a furnace system:

  1. Check the Fan Setting: Ensure that the fan limit switch is set to the “auto” position instead of the “on” position. In “auto” mode, the fan runs only during the heating cycle, while the “on” position results in the fan running continuously.
  2. Look for Shorted Wires: If the fan does not start in the “auto” mode, inspect the fan limit switch to see if any wires are shorted or broken. A shorted wire can cause the switch to malfunction, leading to issues with the fan.
  3. Check the Temperature Settings: In case the fan continues to blow cold air, check the temperature setting on the thermostat. If the temperature is set to a lower temperature than the current space temperature, the fan will continue to run, causing cold air circulation.
  4. Clean Ductwork and Furnace Hood: Dirt and debris in the ductwork and furnace hood can result in the fan operating poorly. A thorough cleaning of ductwork and furnace hood can fix fan limit switch issues.

To avoid such issues, ensure the fan limit switch is well-maintained and serviced regularly by professional HVAC technicians. Additionally, upgrading to a programmable thermostat can provide better control of the heating and cooling system, reducing energy consumption and costs.

Finding the fan limit switch is like playing a game of hide-and-seek with your furnace, but trust me, it’s worth it.

Identifying the Fan Limit Switch

The Fan Limit Switch is a must-have component in HVAC systems. It helps keep your home’s temperature and efficiency in check. 

To identify it, consult the table below:

Location of Fan Limit SwitchType of HVAC System
Close to the blowerGas or oil furnaces
On the air ductElectric furnaces

Knowing the type of system you have will show you where the switch is located.

It’s vital to take care of any issues with the fan limit switch ASAP. If it’s not taken care of, costly repairs may follow. If you think your fan limit switch is on the fritz, get help right away. Don’t take risks with your home’s comfort and safety.

Checking for Shorted Wires

In need of fan limit switch troubleshooting? Make sure there aren’t any shorted wires. 

Here’s a guide to help you out:

  1. Turn off all power first.
  2. Look for signs of damage on wires and connections coming from the switch.
  3. Disconnect the wire from both the fan limit switch and furnace control board.
  4. Use a multimeter to check for continuity between the two points. If there’s continuity, there’re no shorts.
  5. If there’s infinite resistance reading, it means that the wire is shorted.
  6. Replace with fresh wiring of appropriate gauge and length.

Keep in mind that wire insulation damage could be caused by overheating. If so, investigate why the wiring is heated up.

Be extra careful when doing electrical work as shocks and fires are a real danger. It’s best if you have basic knowledge of electricity before attempting any repairs.

If all else fails, replace your fan limit switch for a more reliable system.

Replacing the Fan Limit Switch

Replacing the fan limit switch can be tricky, but it’s doable. 

Here are four easy steps to help you do it like a pro:

  1. Cut the power: Before starting, make sure to turn off the main power supply for safety.
  2. Unscrew & remove: Carefully unscrew and remove the old fan limit switch from its spot.
  3. Install new switch: Put in the new fan limit switch in the same place as the old one. Secure it with screws.
  4. Test & turn on power: Test the switch to make sure it’s working. Lastly, turn on the power supply.

Remember that buy a fan limit switch compatible with your heating system for best performance. Replacing it can save you costly repairs down the road. A faulty fan limit switch can cause overheating and poor air circulation, leading to a breakdown of your system. So change it in time for optimal performance.

Also, fan control switches have been around since World War II. Back then, US Air Force pilots used them to regulate cabin temperature at high altitudes, where cabins can reach extreme temperatures, which posed health risks for the pilots. So these switches are essential for living healthy lives.

Making Adjustments to the Thermostat

Adjusting thermostat settings can help with furnace fan circulation. Use the fan limit switch to set the temperature and time intervals for the fan to run. In the summer, switch to the “fan on” setting for constant circulation. To override this setting, switch to “auto.” If you need further assistance, call a professional HVAC technician.

It is important to ensure the furnace hood is securely attached to avoid shorted wires.

Changing the Fan Setting from Auto to On

For better air quality and lower energy bills, switch the fan setting from auto to on. Here’s how:

  1. Locate the thermostat and flip it to ‘fan on.’
  2. Wait for the blower to keep running.
  3. Check the filters often. The fan-on setting can make them dirtier faster.
  4. Set the temperature to your comfort level. This setting usually works best when the temperature is lower.
  5. When leaving home for a while, switch back to ‘auto’ mode. It’s more energy efficient.

Remember that long-term use of ‘fan on’ mode can cause higher electricity bills and bad air quality if filters aren’t cleaned.

Pro Tip: Monitor energy usage and air quality by alternating ‘auto’ and ‘on’ modes according to your family’s habits.

Finding the perfect balance between hot and cold is like being both a polar bear and a tropical bird.

Setting the Temperature and Fan Speed

Optimal temp and fan speed are musts for any HVAC system. 

Here’s how to set them:

  1. Adjust the thermostat. Choose a comfy temperature; cool or heat, up to you!
  2. Aim for steady. Keeping it constant saves energy and costs.
  3. Select fan speed. Low, medium, or high-pick according to needs.
  4. Calibrate occasionally. To keep the system running optimally.
  5. Clean air filters. Blockages caused by dirt and dust impede airflow.

For best system performance, clean air filters and calibrate sensors often. For heating, low fan speed is usual; but in humid summers, higher speed helps remove moisture and makes your home cooler.

Using the Manual Override Button

To get your furnace fan running continuously, use the manual override button.

  1. Locate the Fan Limit Switch on your Furnace Hood.
  2. Find the White Button on the Switch.
  3. Press it to Engage the Manual Override Function.

Using the manual override feature can help with air circulation during hot summer months or in one space. But, don’t use it as a long-term solution. If you find yourself needing to use it constantly, seek professional help.

Sometimes people think they need a new HVAC unit if their furnace isn’t running correctly. Not always. Replacing a shorted wire or fixing other small issues can get things running again. At our Phoenix-based HVAC services center, we’ve saved homeowners time and energy by taking care of these smaller issues. So, if you’re having furnace problems this season, give us a call.

Checking the Ductwork and Furnace Hood

As part of ensuring proper furnace functioning, it is necessary to inspect and maintain the ductwork and furnace hood. This helps to avoid issues like cold air blowing into your home during winter months. 

Here is how to go about it:

  1. Use a flashlight to look inside the ductwork and check for any signs of wear, tear or disconnection. This is especially important if your home has been through a renovation or if the ductwork is old.
  2. Inspect the furnace hood for any debris that could be blocking it. Debris could be leaves, dirt, and any other foreign object. Ensure that the furnace hood is clean at all times to allow the heated air to flow freely.
  3. Clean the ductwork and furnace hood regularly. It is recommended to have a professional HVAC technician conduct annual servicing for your furnace system.

Remember to turn off the power to the furnace system before you commence any inspection or cleaning.

Pro Tip: If after inspecting the ductwork and furnace hood, you notice any issue with the furnace system, do not attempt to fix it yourself. Call in an experienced HVAC technician for assistance.

Time to play detective and see if your furnace has any dirty little secrets like blockages or leaks.

Inspecting for Any Blockages or Leaks

When it comes to furnace and ductwork upkeep, it’s essential to check for blockages and leaks. Inspecting your home’s heating system can save you money and keep you safe from poor air quality.

Follow these five simple steps for your furnace and ductwork maintenance:

  1. Turn off your thermostat.
  2. Check your air filter for debris and change if needed.
  3. Examine the ductwork for any visible damage like tears, holes, or rust spots. Use a flashlight for better visibility.
  4. Check the furnace hood for any blockages or debris. Make sure there are no flammable materials nearby.
  5. Contact a professional HVAC contractor if something is off.

Also, make sure your home is well-insulated. This prevents heat loss and increases energy efficiency.

One homeowner didn’t do their annual inspection and had to pay twice the amount for furnace repair during a winter storm. Don’t leave it too late, check it now. It may be uncomfortable, but ductwork and furnace maintenance is necessary for optimal airflow.

Cleaning the Ductwork and Furnace Hood

It’s important to clean your ductwork and furnace hood to ensure proper ventilation and heating. 

Here’s a four-step guide on how to do it:

  1. Turn off the power supply to the furnace.
  2. Remove the registers or grilles from the vent openings and wash them with a mild detergent and warm water.
  3. Use a vacuum cleaner with a long hose attachment to get rid of dust, debris, and other particles inside the ducts.
  4. Check the furnace hood for any blockage or damage, and clean it with a soft-bristled brush.

Inspect your ductwork yearly for leaks, moisture accumulation, and mold growth. These issues can harm indoor air quality and cause health problems.

I recently had my ductwork professionally cleaned and noticed an immediate difference in air quality. This highlights how essential it is to maintain your HVAC system for your health and overall wellbeing. Don’t worry, though, your energy bill won’t skyrocket.

Considering the Time and Space for Continuous Fan Operation

As a professional in the HVAC industry, it is important to consider both the time and space for continuous fan operation in a furnace system. The fan limit switch, located in the furnace hood, controls the blower motor and dictates when the fan turns on and off.

To ensure proper circulation and temperature control in the home, the fan limit switch should be set to “auto” during the heating cycle, and “on” during the summer months to prevent stagnant air in the ductwork.

It is important to note that continuous fan operation can lead to an increase in energy consumption and may be unnecessary in some homes or spaces. It is recommended to consult with an HVAC technician to determine if continuous fan operation is necessary.

Pro Tip: If the fan does not run on the “on” or “manual override” setting, it may be due to a shorted wire or an issue with the fan motor. In this case, it is best to call a professional for assistance.

My furnace fan runs more than I do, but hey, it keeps the air circulating.

Determining the Need for Continuous Fan Operation

Continuous fan operation may be essential in certain scenarios. To decide, time, space, and environment must be taken into account. Room size, occupancy, temperature, and humidity must be examined. Potential risks such as excessive noise or power consumption must also be considered.

Not all settings require continuous fan use. For example, a smaller, quieter room may not need it; whereas a large busy one may benefit from it. External elements like air quality should also be taken into account.

Unique details can help determine if fans are needed. Monitoring CO2 levels reveals air freshness and circulation needs. Tracking temperature changes helps optimize fan usage for when it’s most beneficial.

Smart technology can adjust fan speed based on pollutants. Multiple fans in strategic locations can be more effective than just one central unit. Regular maintenance and cleaning improves performance and efficiency.

Keep energy usage in check, unless you’re trying to start a blackout.

Monitoring the Energy Consumption

Monitoring electrical appliance usage is key for conserving energy. Keeping track of power consumption helps make smart decisions. 

Check out the power consumption and hours of use per day for some popular appliances:

  • Ceiling Fan: 75 Watts, 18 hours of use per day, 1.35 Kilowatt-hours of energy consumed per day.
  • Air Conditioner: 1300 Watts, 5 hours of use per day, 6.5 Kilowatt-hours of energy consumed per day.
  • Refrigerator: 200 Watts, 24 hours of use per day, 4.8 Kilowatt-hours of energy consumed per day.

It’s clear that using air conditioners often can increase monthly utility bills. Instead, using ceiling fans frequently is more cost-effective and sustainable.

Set a schedule for when to turn on and off electrical appliances. This will cut back on energy consumption and benefit the environment. Track your power usage to save money and contribute to preserving natural resources. Don’t miss out on the chance to make a positive impact. Let professionals handle HVAC to stay cool and comfortable.

Seeking Professional HVAC Services

When experiencing issues with your HVAC system, it is essential to seek the help of professional technicians. Professional HVAC services can assist in repairing and maintaining your furnace, ensuring optimal heating and cooling. With years of experience, the team can diagnose and solve problems, ensuring your system runs efficiently and effectively.

You may notice problems with your furnace’s fan, and while you may be tempted to fix it yourself, it’s best to call a professional HVAC service. A shorted wire or damaged fan limit switch can be complicated to repair, and attempting to do so yourself can cause further damage. Instead, trust a professional to carefully examine your system and provide a solution.

It’s essential to note that different areas may have unique HVAC needs. For instance, in Phoenix, the summer switch may be beneficial to use during the summer season. That’s why it’s crucial to seek professional HVAC services to address your specific needs, ensuring your system runs efficiently while saving energy and money.

A family in cold weather experienced an issue with their furnace system; the furnace hood and motor were covered in ice, causing the heated air to not circulate properly. The professional HVAC technician quickly diagnosed and repaired the issue, ensuring the family had heat restored throughout their home within minutes. Trust a professional in ensuring your HVAC system runs correctly, especially in emergency situations.

When to Call a Professional for Help

HVAC systems are important for our comfort, but need care. When to call a pro? If you notice signs like strange noises, bad temps or higher bills, then it’s time to seek help. They can examine the issue and take preventive measures before damage.

Call immediately if you sense a decrease in air flow, or smell something off from the vents. These could be signs of mold or something more serious, requiring repair or replacement. Experts can assess the situation & resolve it before it gets worse.

Sometimes only minor adjustments are needed, other times major repairs or replacements. Find a trustworthy HVAC company to perform needed services and keep your system running at its best. Regular maintenance prevents breakdowns, saving money.

Annual check-ups are a must. Keep records of your system’s history for future diagnoses. Consider upgrading an old system to save on utility bills with energy-efficient models, instead of costly repairs each year.

Conclusion: Be alert for any HVAC problems. Get regular check-ups to keep everything running well. Don’t wait for issues to become major. Finding a reliable and affordable HVAC technician is hard.

Selecting Reliable HVAC Technicians in Phoenix

Finding a dependable HVAC technician in Phoenix can be daunting. To ensure your system functions well, employ experienced and adept professionals. 

Here are some useful tips to bear in mind when recruiting an HVAC technician in Phoenix:

  • Examine Experience: Look for technicians who have been in the business for years.
  • Verify Certification and Licensing: Make sure the technician is certified and licensed by recognized Arizona bodies.
  • Research Referrals and Reviews: Before engaging HVAC services, check out referrals from other customers or read online reviews.
  • Inquire About Emergency Services: Opt for an HVAC service provider that offers 24/7 repairs to fix unexpected issues with your system.
  • Cost-Effectiveness: Look for budget-friendly solutions without compromising work quality.

When selecting reliable HVAC technicians in Phoenix, don’t hurry. Do thorough research. Ask about their expertise with your system type. Professionalism, communication skills, and promptness should also be top priorities.

Keep in mind that proper maintenance extends your system’s lifespan. Regular upkeep helps you get the most out of your investment while avoiding costly repairs due to negligence. According to Energy Star, properly fitted and maintained systems can save up to 21% on energy costs.

For hot air or cold shoulders, professional HVAC services are always the chill choice.


Do you want your furnace fan to run continuously? No worries. As a seasoned heating and cooling technician, here are a few tips. Check your thermostat. It’ll have two options for controlling the fan, ‘auto’ and ‘on’. Select ‘on’ for continuous air circulation. But, if your furnace has a summer switch, ensure it’s set to ‘off’. Next, review your fan limit switch. It’s a safety control to prevent overheating and it’ll turn off the burner if the air gets too hot. If it’s defective or set too low, it could stop the fan too soon. Adjust it to your needs. Try a manual override. Use the white button on the side of the furnace hood to switch on the blower motor. But, stay cautious. Don’t touch any wires or electrical components as this could result in short circuits and other issues. For quality HVAC services in Phoenix and the surrounding areas, contact us today.