When a furnace shuts down unexpectedly or blows cold air, most homeowners look for one thing first—the reset button. This small, often red or yellow button is a safety device designed to shut the furnace off when conditions become unsafe. Pressing it can temporarily restore heat, but only if the underlying issue is minor and the system is safe to restart.
Most furnaces position the reset button inside the blower compartment, usually attached to the blower motor or a nearby safety switch. However, the exact location varies significantly depending on whether the furnace is gas, electric, high-efficiency, or oil-fired. Newer digital furnaces may not have a manual reset button at all.
Understanding where the reset button is located—and when you should or should not press it—is essential for safe operation. This guide explains where to find it, how to use it, what it looks like, and what to do when a reset doesn’t solve the problem.
What the Furnace Reset Button Does
The reset button activates when the furnace detects unsafe operating conditions. It stops the burner or blower to prevent overheating, combustion failure, electrical overload, or damage to the furnace system. Common triggers include restricted airflow, ignition failure, dirty burners, failed igniters, or overheating due to blocked vents.
This safety response protects both the equipment and the home. Pressing the button forces the furnace to attempt another heating cycle—but if the underlying issue remains, the system usually shuts down again. Repeated resets can create unsafe conditions, especially in fuel-burning systems.
Where the Furnace Reset Button Is Located
The reset button is almost always located inside the furnace cabinet behind one or two access panels. Its visibility and placement depend heavily on furnace type, brand, and age.
Common Reset Button Locations by Furnace Style
| Furnace Type | Reset Button Location | Distinguishing Characteristics |
|---|---|---|
| Standard gas furnace | Inside blower compartment, near blower motor | Typically a red or yellow button |
| High-efficiency (condensing) furnace | Behind lower access panel, near motor or control board | May require removing two panels |
| Electric furnace | On or near blower motor housing | Sometimes behind an internal cover |
| Oil furnace | Near burner motor or on the primary control module | Often a large red button |
| Older furnaces | Under or behind blower motor assembly | May require more disassembly |
| Furnaces with no reset button | No manual reset option | Reset performed via power cycle |
Although most reset buttons are obvious once seen, some models tuck them behind wiring harnesses or brackets, making them harder to spot.
What the Reset Button Looks Like
Homeowners often ask how to identify the reset button quickly. Most reset buttons share several common traits: they are round in shape, usually about half an inch wide, and typically colored red or yellow. When tripped, the button pops outward and makes a click sound when pressed back in.
It is generally mounted to the blower motor housing or attached to a limit switch. Some high-efficiency units use recessed reset switches located on the control board rather than a protruding button. Oil furnaces, on the other hand, typically feature a large, unmistakable red button that protrudes prominently from the burner controller, making it easy to spot.
How to Reset a Furnace Safely
Before you proceed with resetting your furnace, it’s important to understand some key safety guidelines to ensure you do so correctly and avoid potential hazards.
- Reset the furnace only once to avoid fuel buildup or electrical overload.
- Never press the reset button if you detect a gas smell or burning odor.
- Allow the furnace to cool for 15–30 minutes if it overheated.
- Do not turn the furnace on and off repeatedly during ignition attempts.
- If the system shuts down again after a reset, schedule professional service.
These basic safety precautions ensure you do not accidentally worsen the underlying problem or create a hazardous condition.
Step-by-Step Instructions to Reset a Furnace
Homeowners can safely reset a furnace using a simple, structured approach:
1. Turn off the power
Use the furnace power switch or breaker. This prevents accidental ignition while accessing internal components.
2. Remove the access panel
Most furnaces require lifting or unscrewing the blower door to reach the internal controls.
3. Locate the reset button
Look near the blower motor housing. Some models place it on a high-limit switch attached to the heat exchanger.
4. Press and hold the button for 3–10 seconds
If the button was tripped, it will click and return to a seated position.
5. Restore power to the furnace
Turn the switch or breaker back on and allow the furnace to initiate its startup cycle.
6. Observe the furnace
Listen for the igniter, gas valve, and blower to activate. Check that warm air begins flowing within a few minutes.
7. Stop immediately if the furnace shuts down again
Persistent shutdowns indicate problems that require professional diagnosis.
Resetting Furnaces That Don’t Have a Reset Button
Newer digital furnaces may lack a physical reset button entirely. Instead, they use control boards that reset electronically.
Reset Alternatives for Button-less Furnaces
| Reset Method | How It Works | When to Use It |
|---|---|---|
| Power-cycle reset | Turn furnace breaker off 5–10 minutes | Furnace stuck in error mode |
| Thermostat reset | Switch system to OFF, wait, then restart | Communication issues |
| Panel-door safety switch | Ensure blower door is fully latched | Furnace won’t start after filter change |
| Control board micro reset | Small recessed button on newer boards | Used for board-level resets |
These methods perform the same function as a traditional reset button without requiring a mechanical switch.
Why the Furnace Reset Button Trips
Several common issues can cause the furnace reset button to trip, signaling that the system has detected an unsafe condition requiring immediate shutdown to protect the equipment and your home. These problems often relate to airflow restrictions, ignition failures, or electrical faults. Typical causes include:
- Dirty furnace filter causing overheating
- Blocked or closed supply or return vents
- Dirty burners or misaligned ignition system
- Flame sensor unable to detect flame
- Faulty igniter or weak spark
- High-limit switch detecting unsafe temperature
- Blower motor overload
- Gas supply inconsistencies or interruption
- Faulty control board or relays
Identifying these issues early and addressing them promptly can prevent repeated shutdowns and costly repairs, ensuring your heating system operates safely and efficiently.
Resetting an Oil Furnace
Oil furnaces behave differently from gas or electric systems. The reset button is usually bright red and positioned on the primary control module attached to the burner assembly. Pressing the button commands the system to spray fuel and attempt ignition.
An oil furnace must never be reset more than once. Repeated resets introduce unburned oil into the combustion chamber, increasing the risk of a “puffback”—a sudden release of soot and smoke that can damage the home.
What to Do if the Furnace Doesn’t Start After Resetting
If the furnace still refuses to start after a single reset, it is signaling a deeper problem. Common causes include:
- Failed ignition sequence
- Dirty or malfunctioning flame sensor
- Clogged burners
- Overheating caused by airflow restrictions
- Cracked or failing heat exchanger
- Gas valve malfunction
- Blower motor failure
- Faulty thermostat communication
In cold climates such as North Central Minnesota, furnaces also work harder and cycle more frequently, which increases stress on ignition components. Professional diagnosis is the safest option to restore dependable heat.
Resetting a Furnace After a Power Outage
Power outages often interrupt the furnace’s startup logic. After restoring power:
- Confirm that the thermostat is calling for heat.
- Check that the furnace power switch is turned on.
- Ensure the blower door is fully secured.
- Consider cycling the breaker off for 5–10 minutes for a soft reset.
- Attempt a single reset if the furnace fails to ignite.
If the furnace hums, clicks repeatedly, or shuts down again, internal components may require attention.
Preventing Future Reset Button Trips
Regularly replacing furnace filters ensures proper airflow and prevents overheating. Keep vents and returns open to avoid strain on the system. Annual cleaning of burners, igniters, and flame sensors maintains performance and reduces shutdown risks.
Properly sealed ductwork supports blower motor longevity. Avoid frequent large thermostat adjustments to reduce cycling and wear. Installing carbon monoxide detectors near bedrooms adds an important safety measure. Following these steps helps minimize furnace shutdowns and ensures safe, efficient operation throughout the heating season.
FAQs About Resetting a Furnace
What Does a Furnace Reset Button Look Like?
It is usually small, round, and red or yellow. It pops outward when tripped and clicks when pushed back into place.
How Do You Know if Your Furnace Needs to be Reset?
If the furnace has shut down, blows cold air, or fails to ignite after a thermostat call for heat, the reset button may have been triggered.
How Do I Manually Reset My Furnace?
Shut off power, open the blower compartment, locate the red or yellow reset button, press it, restore power, and allow the furnace to restart.
Do All Furnaces Have a Reset Switch?
No. Many modern furnaces rely solely on electronic control boards. These systems reset through power cycling or the control board’s micro reset mechanism.
Why Does My Reset Button Keep Tripping?
Repeated trips usually point to overheating, ignition problems, airflow blockages, or flame-sensing issues. This requires professional inspection.
Professional Furnace Service in North Central Minnesota
If your furnace continues tripping the reset button, shuts down repeatedly, or refuses to ignite, the safest course is to schedule a professional diagnostic. Neighborhood Plumbing, Heating, A/C & Electrical provides full furnace repair, ignition system evaluation, airflow troubleshooting, and safety inspections throughout North Central Minnesota.
To schedule an appointment, visit our Contact Us page.