Safely Relight Your Furnace in 8 Simple Steps

Safely Relight Your Furnace in 8 Simple Steps

As the seasons change, ensuring your home remains a haven of comfort is crucial. One key aspect of this comfort is maintaining a warm and cozy environment, especially during the colder months. This often means making sure your furnace is in working order. Whether it’s been shut off for the summer or you’ve encountered a minor hiccup requiring a restart, relighting your furnace is a task that, while seemingly simple, demands care and understanding to ensure safety and efficiency. In this comprehensive guide, we’ll walk you through the steps to safely relight your furnace, outline common mistakes to avoid, and provide essential safety tips to keep your home warm and risk-free.

Understanding Your Furnace

Before embarking on the journey of relighting your furnace, it’s crucial to grasp the basics of how your furnace operates and the types you might encounter. This knowledge not only aids in the relighting process but also helps in troubleshooting should any issues arise. Most residential furnaces are either gas or electric, with gas furnaces being more common in areas where natural gas is readily available and cost-effective.

Types of Furnaces

1. Gas Furnaces: These are the most prevalent types of furnaces in homes that use natural gas or propane as fuel. Gas furnaces heat the home by burning gas in a combustion chamber, and this heat is then transferred to the air circulating through the home’s ductwork.
2. Electric Furnaces: Electric furnaces use electric heating elements to heat air, similar to how a toaster works. These are typically found in areas where electricity is less expensive than gas or where gas is not available.
3. Oil Furnaces: Less common, oil furnaces operate by burning oil to produce heat. They are primarily found in areas where other fuels are not as accessible.

Components of a Gas Furnace

To safely relight your furnace, focusing on gas furnaces, you’ll need to be familiar with a few key components:

• Thermostat: This device controls the temperature in your home and signals the furnace to turn on or off.
• Gas Valve: Controls the flow of gas to the furnace. It has several positions including “off,” “on,” and “pilot.”
• Pilot Light: A small flame that ignites the gas burner. In modern furnaces, this may be replaced by an electronic ignition system.
• Burners: The part of the furnace where gas is ignited to produce heat.
• Heat Exchanger: Separates the combustion process from your indoor air, ensuring only clean, warm air is circulated through your home.
• Blower Motor: Circulates air through the heat exchanger and into your home’s ductwork.

Pilot Light vs. Electronic Ignition

Older furnaces often use a pilot light that burns continuously, ready to ignite the main burner gas when the thermostat calls for heat. Newer models, however, may use electronic ignition systems, which only ignite the burner gas as needed, improving efficiency and safety. Knowing which system your furnace uses is vital, as the process for relighting or troubleshooting will differ.

Importance of the Model and Manual

Each furnace model has its own specific set of instructions for operation, maintenance, and troubleshooting. Before attempting to relight your furnace, locate your furnace’s manual. It will provide invaluable information tailored to your specific model, including detailed instructions on how to safely relight the pilot light or reset the electronic ignition system.

Safety Precautions

When dealing with any furnace, especially when attempting to relight a pilot light or perform maintenance, safety should always be your top priority. Gas furnaces, while efficient and common, involve the handling of natural gas, which can be dangerous if not managed properly. Here are essential safety precautions to ensure the process is safe and to prevent any accidents or damage to your home.

1. Read Your Furnace Manual

Before you do anything, consult your furnace’s user manual. It contains specific safety warnings, maintenance tips, and instructions tailored to your model. This is crucial because every furnace can have slightly different operating procedures and safety features.

2. Turn Off the Gas

Always turn off the gas supply to the furnace before attempting to relight the pilot light. This minimizes the risk of gas buildup or accidental ignition of excess gas. Typically, you should wait at least 5 minutes after turning off the gas to allow any residual gas to dissipate, reducing the risk of a gas explosion.

3. Inspect for Gas Leaks

Before relighting the furnace, check for signs of a gas leak. The smell of sulfur or rotten eggs is a common indicator. If you suspect a gas leak, do not attempt to relight the pilot light or use any electronic devices or open flames in the area. Evacuate immediately and contact your gas company or a professional HVAC technician from a safe distance.

4. Ensure Proper Ventilation

Make sure the area around the furnace is well-ventilated. This helps to prevent any accumulation of gas fumes in the event of a minor leak or when the gas is turned back on. Open doors or windows in the furnace room if possible.

5. Use Appropriate Lighting Tools

If your furnace requires manual lighting, use a long-reach lighter or match to safely ignite the pilot light. This keeps your hands and face away from the flame and reduces the risk of burns.

6. Wear Protective Clothing

Wearing protective gloves and glasses can provide an extra layer of safety, especially when you’re dealing with older furnaces that may have sharp edges or when using matches or lighters.

7. Know When to Call a Professional

If at any point you feel unsure or uncomfortable with the process, or if the furnace does not light after several attempts, it’s best to call a professional. HVAC technicians are trained to handle these situations safely and efficiently. Additionally, if your furnace has a history of operational issues, professional inspection and maintenance may be necessary to ensure it’s safe to use.

8. Regular Maintenance Checks

Preventive maintenance is key to safe furnace operation. Have a certified HVAC professional inspect and service your furnace annually to ensure it’s in good working condition and to prevent potential safety hazards.

9. Monitor Carbon Monoxide Detectors

Ensure your home is equipped with carbon monoxide detectors near sleeping areas and on each level of your home, including the basement. These devices can alert you to the presence of carbon monoxide, a colorless, odorless gas that can be deadly. Check these detectors regularly to ensure they are functioning properly.

Step-by-Step Guide to Relighting Your Furnace

Relighting your furnace’s pilot light can seem daunting, but with careful adherence to safety measures and detailed instructions, it can be a straightforward process. This guide focuses on gas furnaces with a pilot light, as electronic ignition systems typically do not require manual relighting. Before proceeding, ensure you’ve taken all necessary safety precautions.

Step 1: Locate the Pilot Light Assembly and Gas Valve

• Pilot Light Assembly: This is usually found at the bottom of the furnace. You may need to remove a cover or access panel to see it.
• Gas Valve: This valve controls the gas flow to the pilot light and main burner. It typically has three settings: “Off,” “Pilot,” and “On.”

Step 2: Turn Off the Gas Valve

• Turn the gas valve to the “Off” position to stop the flow of gas to the furnace. Wait at least 5 minutes to allow any residual gas to dissipate. This waiting period ensures any gas that has accumulated in the air is cleared, minimizing the risk of ignition.

Step 3: Set the Valve to Pilot

• After ensuring there is no smell of gas, turn the gas valve to the “Pilot” position. This setting allows gas to flow only to the pilot light, not the main burner.

Step 4: Ignite the Pilot Light

• Hold down the reset button or knob (found near the gas valve), which allows gas to flow to the pilot. While holding the button, use a long match or a barbecue lighter to light the pilot light. The reset button or knob may need to be held down for 30-60 seconds after the pilot light ignites to ensure the thermocouple or flame sensor heats up enough to detect the flame and keep the gas flowing.

Step 5: Check the Flame

• Once lit, the pilot flame should be steady and blue, with a slight yellow tip. A strong blue flame indicates a good burn. If the flame is weak, yellow, or goes out frequently, there may be an issue with the pilot light opening or gas supply that needs professional attention.

Step 6: Turn the Gas Valve to On

• After the pilot light is burning steadily, release the reset button and turn the gas valve to the “On” position. This will allow gas to flow to the main burner.
• Listen for the main burner to ignite, indicating the furnace is operational. You should hear a whooshing sound as the burner ignites.

Step 7: Replace the Furnace Cover

• Once the furnace is lit and running properly, replace any covers or access panels you removed during the process.

Step 8: Set Your Thermostat

• Finally, adjust your thermostat to the desired temperature. The furnace should respond to the thermostat setting and begin heating your home.

Troubleshooting Common Issues When Relighting Your Furnace

After attempting to relight your furnace, you might encounter some issues that prevent the furnace from operating correctly. Here are some common problems and troubleshooting tips to help you address them safely. If these steps do not resolve the issue, it’s important to consult with a professional HVAC technician to avoid risking your safety or causing damage to your furnace.

The Pilot Light Won’t Stay Lit

• Faulty Thermocouple: The thermocouple is a safety device that detects whether the pilot light is lit. If it’s malfunctioning or misaligned, it may shut off the gas to the pilot light, preventing it from staying lit. Try adjusting the thermocouple so it’s in the flame of the pilot light. If this doesn’t work, the thermocouple may need to be replaced.
• Dirty Pilot Orifice: A clogged pilot orifice can prevent gas from reaching the pilot light. Cleaning the orifice with a needle or a specialized brush can help, but be careful not to damage it.

Furnace Doesn’t Start After Relighting

• Gas Valve Issues: Ensure the gas valve is turned fully to the “On” position. If it’s stuck or faulty, it may not allow gas to flow to the burners.
• Thermostat Settings: Double-check that the thermostat is set to “Heat” and that the temperature setting is above the current room temperature. Sometimes the issue is as simple as the thermostat not signaling the furnace to start.
• Electrical Issues: For furnaces with electronic controls, a tripped circuit breaker or blown fuse can prevent the furnace from starting. Check your home’s electrical panel and reset any tripped breakers or replace blown fuses.

Weak or Yellow Pilot Flame

• Gas Pressure Problems: A weak or yellow flame indicates poor gas pressure or an issue with the gas mixture. This could be due to a variety of factors, including issues with your gas supply. Contacting your gas company or a professional is advised.
• Airflow Obstructions: Ensure there’s no debris or obstruction around the furnace’s air intake or exhaust. Blocked airflow can affect the combustion process, leading to a weak flame.

The furnace Starts but Doesn’t Heat Adequately

• Dirty Air Filter: A clogged air filter can restrict airflow, reducing the furnace’s efficiency and its ability to heat your home. Replacing the air filter might resolve the issue.
• Ductwork Issues: Leaks or blockages in your ductwork can significantly reduce heating efficiency. Inspect accessible ducts for leaks and ensure registers are open and unblocked.

The furnace Turns Off and On Frequently

• Overheating: If the furnace overheats, it may shut off frequently to prevent damage. This can be caused by restricted airflow from a dirty air filter or blocked vents. Check and replace the air filter if necessary.
• Faulty Flame Sensor: A dirty or faulty flame sensor can cause the furnace to shut off as a safety measure if it incorrectly senses no flame. Cleaning or replacing the flame sensor can solve this issue.