What To Do When Your Furnace Won't Turn Off in Andover

When a furnace stops working, it gets your attention right away. But if your furnace won't turn off, that can be just as frustrating and even more confusing. If you're in Andover and your furnace keeps running non-stop, it's important not to ignore the issue. Besides wasting energy, a furnace that doesn’t shut off can wear out faster and create an uncomfortable indoor climate.

Every furnace has a limit to how much it should run. When it continues beyond typical cycles, there’s usually a specific reason. The good news is that some issues can be recognized early if you know what to watch for. Taking action quickly can help prevent larger repairs, higher bills, or safety risks inside your home.

Understanding Why Your Furnace Won't Turn Off

When a furnace keeps running, one of the first things to think about is the thermostat. This small device controls when your furnace turns on and off based on the temperature setting. If it’s broken, miswired, or set incorrectly, it may continue signaling the furnace to run. For example, if the fan is set to "on" instead of "auto", it will continue to blow even when the furnace isn’t actively heating.

Other possible causes include:

- Limit switch problems: The limit switch controls how long the blower runs during heating cycles. A faulty switch can keep the blower operating even when it shouldn’t be.

- Dirty furnace filter: When air filters get clogged with dust and debris, the furnace has to work harder to push air. This can trigger long run times or keep the blower running to clear heat.

- Wiring issues: Loose or damaged wiring can disrupt the communication between controls and the furnace system, leading to unusual symptoms like continuous operation.

- Blocked or closed vents: When vents are closed or blocked, air can't circulate properly. This may make the system think it hasn’t heated the space enough, triggering more runtime.

- Fan relay stuck: In some cases, a stuck fan relay can keep the fan motor running regardless of commands from the thermostat.

Let’s say your thermostat is set to 70 degrees, but the furnace keeps running even at 75. That often means the system isn’t reading the temperature correctly or isn’t receiving the signal to shut off. Identifying that kind of symptom early can save you from having to replace parts that are working harder than they should.

Steps to Troubleshoot the Issue

Before scheduling a service visit, there are a few things you can check yourself to get a better sense of what might be going on. These steps won’t fix every problem, but they can help you rule out simple causes before turning to our professionals.

Here’s what Andover homeowners can look at:

1. Check thermostat settings

- Make sure it’s set to "auto" and not "on"

- Double-check the temperature setting

- Look to see if the display is working properly

2. Inspect air filters

- Dirty filters block airflow and force the system to work harder

- If it looks gray or dusty, replace it with a clean one

3. Open and clear all vents

- Walk through each room in your home

- Make sure none of the vents are closed, blocked by furniture, or covered by curtains

4. Flip the furnace switch

- There’s usually a power switch on or near your furnace

- Turning it off and on again may reset the system

5. Listen for unusual noises

- Buzzing, humming, or rattling sounds can point to electrical or mechanical issues, like a stuck relay or worn-out blower motor

If none of these steps make a difference and your furnace continues running, that’s a sign the problem goes deeper and needs attention from someone trained to safely inspect the system. Leaving a nonstop furnace alone can damage the unit and push your utility bills higher, especially in the warmer months like August when it should be resting.

When to Call Our Professionals

If you've checked the basic settings and your furnace still won’t shut off, it’s time to get help from our professionals. Some problems can’t be solved without opening the furnace or testing electrical components. That work is best handled by trained technicians who know how to work safely around heating systems.

Here’s when you should bring in our team:

- The thermostat seems fine but the furnace keeps blowing

- You hear humming or buzzing sounds coming from the furnace

- The blower motor won't shut off even when you cut power from the thermostat

- You’ve changed the filter and reset the furnace, but there’s no change

- Temperatures inside your home go well beyond the thermostat setting

- You’re unsure about opening panels or working near wires

Trying to diagnose deeper issues without training can cause more damage. A stuck relay, for example, might burn out other connected parts if left unchecked. If your furnace is older, serious wear and tear could be affecting how its internal controls respond. Our technicians have the tools and training to troubleshoot these problems safely and to get heat settings back under control as quickly as possible.

Furnace Maintenance Tips for Andover Homes

Preventing problems like these often comes down to routine care. Regular furnace maintenance in Andover helps reduce the chance of unexpected breakdowns or non-stop operation. Small checks here and there keep your system running properly through every season it’s in use.

Add these steps to your home care schedule:

- Replace air filters monthly while the furnace is active

- Check that all supply and return vents are clean and open

- Keep the area around the furnace clear of storage bins or clutter

- Inspect the thermostat batteries and connections once per season

- Schedule annual inspections for a full system review

If your home gets regular dust buildup or you have pets, you may want to change filters more often. High airflow resistance can strain the system and shorten its life. Another tip is to keep an eye on noise levels and heat patterns after big weather changes. If something feels off or the system runs louder than usual, it could be a sign parts are wearing out or sensors aren’t reading properly.

Doing these things won’t guarantee your furnace never has problems, but it makes it a lot less likely that you’ll face a surprise issue when you least expect it. Catching misfires early and keeping the system clean are smart ways to avoid more complicated repairs later.

Leave Furnace Troubles to Us

A furnace that won't shut off is more than just a minor issue. It affects how comfortable your home feels and how hard your system works behind the scenes. If you’ve already gone through the basic troubleshooting steps and nothing has changed, it’s time to let our technicians take a closer look. Long-running furnaces can overheat, burn out parts, or cycle improperly, especially during off-seasons like summer when the equipment should stay idle.

Our professionals know how to work with older and newer heating systems and can quickly pinpoint what’s forcing the unit to keep running. They follow tried-and-true diagnostic methods and use equipment designed to check airflow, switches, wiring connections, and control boards for faults. Bringing in the right help not only solves the immediate problem but puts your system in a better place long-term.

Reliable furnace maintenance in Andover can help reduce strange symptoms, lower repair costs, and restore peace of mind. Getting ahead of problems by having the system inspected each year keeps things running predictably. If your system shows signs it's struggling to shut off, taking care of it now can prevent bigger issues from showing up later.

Maintaining a consistently safe and comfortable home environment relies partly on proactive care for your furnace. If you're experiencing issues with endless furnace operation, scheduling regular furnace maintenance in Andover can help catch problems before they require more extensive repairs. MJB Heating & Cooling understands that unexpected furnace issues can disrupt your routine, so our professionals are ready to help diagnose and solve problems quickly. For a quick estimate or to book a service visit, please contact us today.