What is a Furnace Reset Button?

A furnace reset button is an important feature included with your residential HVAC system. Designed to shut the unit off quickly, the function is key to safely heating your home. If your furnace reset button keeps tripping, it’s likely that your furnace is overheating. This may indicate a need for furnace repair services.

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All furnaces are equipped with a reset button. They are generally red or yellow and are located inside the blower compartment. The reset button is a safety feature that will shut down the furnace when a problem is detected, often a hot or overheating furnace, before it trips the circuit breaker.

It's not uncommon for a furnace to require resetting on occasion. However, if the furnace frequently requires resetting, the furnace should be inspected by a furnace repair expert.

What Can Cause the Reset Button to Trip?

Furnace reset buttons may be triggered by several different scenarios, including:

• Loss of Fuel

  If you have a gas or oil furnace, the reset button may trip if you are out of fuel. This fix is as simple as ensuring fuel is in either the gas or oil tank. If this is the case, when you call for a refill, let them know that the tank is empty and will need to be primed.

• Blocked or Closed Gas Valves

  Blocked or closed valves could be another reason the tank reset button keeps tripping. Checking to see if any of the valves have been closed accidentally could help solve the problem.

• Overheating

  If a furnace isn’t receiving enough airflow, it may overheat and trigger the reset button to trip. Make sure to clean or replace the air filters and keep the air vents open enough for proper airflow.

• A Dirty Flame Sensor

  Occasionally, the flame sensor rod may be coated with dirt and debris, causing the furnace to shut off. Keeping the flame sensor rod clean by wiping it off regularly will help keep this from happening.

• A Dirty Air Filter

  A clogged or dirty air filter may cause the furnace to trip. Changing or cleaning your HVAC air filter regularly (at least quarterly) will help to reduce the strain on your furnace and keep it functioning properly.

How to Reset a Gas Furnace

When you are ready to reset your furnace, follow these steps:

1. Make sure the pilot light is out.
2. Turn down the thermostat temperature setting as low as it will go.
3. Turn off the power supply to the furnace by turning off the breaker in the circuit box.
4. Turn off the main gas supply to the furnace, leaving the pilot gas supply line on.
5. Relight the pilot light by holding a lit match to the pilot flame jet’s opening.
6. Turn the circuit breaker back on, and then turn the main gas supply back on.
7. Press and hold the reset button for about 30 seconds and raise the temperature on the thermostat.

How to Reset an Electric Furnace

Electric furnaces are even easier to reset. Follow these simple steps:

1. First, turn off the power supply to the furnace by turning off the breaker in the circuit box.
2. Locate the reset button on the furnace and press it to reset the furnace. It is usually located inside the blower compartment on the side of the blower motor. Be cautious, as the housing may be hot.
3. If the button is popped up, press it down.
4. Return the cover to the blower compartment and turn the power on.

Breathe Easy with Furnace Reset Assistance from Aire Serv

If your unit continues to trip the reset button or if you require assistance in restarting your furnace, choose Aire Serv. Breathe easy knowing our expert technicians are on the job. Call or request an appointment online to get started.

This article is intended for general informational purposes only and may not be applicable to every situation. You are responsible for determining the proper course of action for your home and property. Aire Serv is not responsible for any damages that occur as a result of this blog content or your actions. For the most accurate guidance, contact the Aire Serv location nearest you for a comprehensive, on-site assessment.

FAQs About How to Reset a Furnace

As an industry leader and a brand that is trusted by homeowners and businesses nationwide for our knowledge and experience, we’re happy to answer your HVAC questions. Here are answers to some of the frequently asked questions about furnace troubleshooting.

Where is the reset button on a furnace?

The location of the reset button varies depending on the make and model of your furnace. The button is typically red or yellow plastic and may be marked with a large R. If the furnace has tripped, the button should protrude slightly.

Here are some general guidelines on where to look for your furnace reset button:

• Inside the blower compartment: The furnace reset button is most commonly found inside the air handler unit, which is usually located next to or above the furnace itself. You'll likely need to open a panel to access this area. The panel may pop off or require you to remove screws.
• Near the blower motor: In many modern furnaces, the reset button is conveniently located near the blower motor.
• Older systems: In older furnaces, the reset button might be harder to find and could be underneath or behind the blower motor.

How do I restart a furnace?

Follow these steps to restart a furnace:

1. Turn off the power: Locate the power switch for your furnace (typically a light switch on the side of the unit or a nearby wall) and turn it off.
2. Wait a few minutes: This allows the system to power down fully.
3. Locate the reset button: Find a red or yellow button marked with an R, often found inside the blower compartment near the blower motor.
4. Press the reset button: If the button is sticking out, press it in firmly once. Avoid pressing it repeatedly.
5. Turn the power back on: Flip the furnace power switch back on.
6. Test the furnace: Turn up your thermostat to see if the furnace starts and begins to heat.

If these steps aren’t possible with your furnace setup or fail to resolve the issue, contact an HVAC professional for residential or commercial furnace repair. A trained service professional can show you how to reset your furnace control board and provide tips for future troubleshooting.

What should I do if my furnace keeps shutting off and needs to be reset?

If your furnace keeps shutting off and needs to be reset, an underlying problem likely needs to be addressed. Repeatedly resetting the furnace without fixing the root cause can potentially damage the unit or even create a safety hazard. While an HVAC professional may be needed to resolve the issue, you can attempt these furnace troubleshooting steps:

1. Stop repeatedly resetting: While resetting might temporarily bring the heat back, frequent shutdowns are a sign that something is wrong. Continuing to reset without diagnosing the issue can make the problem worse.
2. Check the air filter: This is the most common reason for a furnace to overheat and shut down. A dirty or clogged air filter restricts airflow, making the furnace work harder and potentially causing it to trip the reset button.
3. Ensure proper airflow: Restricted airflow can lead to overheating. Make sure that all air vents and registers in your home are open and not blocked by furniture, rugs, or other obstructions.
4. Check the thermostat: Ensure your thermostat is set to “Heat” mode and the temperature is set at least a few degrees above the current room temperature. If your thermostat is battery-powered, try replacing the batteries. Make sure your thermostat isn't located near a heat source (like a lamp or direct sunlight) that could give a false reading.
5. Look for error codes: Newer furnaces may have indicator lights that flash in a specific sequence to indicate a problem. Consult your furnace manual or the manufacturer’s website to understand what these error codes mean. This information can be very helpful for a service professional.
6. Inspect the area around the furnace: Ensure there are no obvious obstructions around the furnace itself and that the vent pipes (both intake and exhaust, if visible) are clear of any blockages like snow, ice, or debris.
7. Check the furnace door: Most furnaces have a safety switch that prevents operation if the access door to the blower compartment isn't closed properly.
8. Listen for unusual noises: Pay attention to any strange sounds coming from your furnace, such as banging, rattling, squealing, or grinding. These noises can indicate mechanical problems that might be causing the shutdowns.

If the furnace continues to shut off after you've checked the air filter, ensured proper airflow, and checked the thermostat, call a qualified HVAC service professional.

Safety First: If you smell gas at any point, do not attempt to reset the furnace! Leave your home immediately and call your gas company or the fire department from a safe location. If you are uncomfortable performing any of these troubleshooting steps, it's always best to err on the side of caution and call a professional.

Why does my furnace need repeated resets?

Some of the most common issues that require frequent use of the furnace reset button include:

• Overheating: Overheating can be caused by a faulty limit switch, a problem with the blower motor, or other internal issues.
• Flame sensor problems: A dirty or faulty flame sensor might not be detecting the flame properly, causing the furnace to shut down as a safety measure.
• Faulty wiring or electrical components: Electrical issues can cause a furnace to shut down unexpectedly.
• Cracked heat exchanger: This is a serious safety concern that can lead to carbon monoxide leaks. Contact an HVAC professional to inspect the heat exchanger for cracks.
• Short cycling: Frequent on-and-off cycles can be caused by improper furnace sizing, a faulty thermostat, and other issues.
• Gas supply issues: Although less common, problems with the gas valve or gas pressure could cause intermittent shutdowns.

Is it safe to keep resetting my furnace when it shuts off?

No, it is not safe to repeatedly reset your furnace without addressing the underlying cause of the shutdowns. The furnace reset button is a safety feature: If it keeps tripping, it’s indicating a persistent problem. While continuously resetting the furnace might temporarily restore heat, it can also mask or worsen a serious safety issue or cause further damage to the furnace.

What information does an HVAC professional need about my furnace?

Provide as much information as possible when calling an HVAC service professional to help with a furnace reset issue. Key information that can assist with troubleshooting includes:

• The make and model of your furnace
• How often you’re resetting the furnace
• Any unusual noises or smells
• Whether you've already tried replacing the air filter
• Any error codes displayed on the furnace control panel

How do I reset my furnace once I’ve found the button?

If your electric furnace keeps shutting off and needs to be reset, review whether you’re performing the reset correctly. Once you've found the reset button:

1. Press firmly: Firmly press the reset button.
2. Hold briefly: Hold the button down for a few seconds (usually 1 to 5 seconds).
3. Release: Release the button.

Don't immediately turn the power back on. Wait 5 to 10 minutes—this gives the furnace time to cool down if overheating is the issue while allowing any temporary faults to clear.