How To Turn On Furnace? Step-By-Step Guide, Troubleshooting

Pre-checks before Turning on a Gas Furnace

To ensure a well-functioning home heating system this winter, you need to turn on your gas furnace. But before you do, it’s essential to undertake a few pre-checks. With the following sub-sections in mind, you can help your furnace run efficiently and safely all season: Checking the Thermostat Setting, Checking the Gas Supply, and Checking the Filter.

How To Turn On Furnace

Image of a gas furnace

Check the Thermostat Setting

Before starting up your gas furnace, double-check that the thermostat setting is right. Ensure it’s set to a temperature you and your family feel comfortable with.

Check the displayed temperature to make sure it matches your desired indoor temperature. Also, make sure the fan mode is off because running it unnecessarily can harm your furnace’s parts.

Program a smart thermostat to automatically adjust temperature settings based on your schedule, or use programmable setbacks when you’re away. This way, you can stay comfy and save money on utility bills.

PRO TIP: Get an HVAC technician to perform maintenance checks on your furnace at least annually. This prevents fuel leaks and malfunctioning parts.

And lastly, verify your gas supply is in working order. Otherwise, your heating system will be colder than your ex’s heart!

Check Gas Supply

Check the gas supply to make sure the furnace starts correctly. Open the main valve and use a detector to look for any leaks. Then, check the pilot light to see if it lights up. Turn the furnace off for at least five minutes to remove any gas left over, then switch it on again. If the light isn’t burning properly, call a technician. Regularly checking and maintaining your gas supply prevents accidents.

Remember to change the air filter every three months. Blockages in the unit result from a neglected filter. Check the thermostat too, because a malfunctioning one can be the reason for heating issues. Try replacing it with a newer model compatible with your furnace.

By taking these precautions, you’ll both prevent danger and keep your furnace running efficiently. Don’t forget to check the filter as no one likes a dusty, musty hot air balloon.

Check the Filter

Before turning on a gas furnace, it’s important to check the filtration system. Neglecting this can cause reduced energy efficiency, high utility costs, and bad indoor air quality.

To keep your furnace filters in good condition:

Furnace air filterHigh-efficiency particulateGas line filter
Change or clean every three months.Replace every 6-12 months.Consult a professional for service annually or biannually.

Don’t forget to follow the recommended frequency schedule for each filter type. If the filter is dirty or clogged, clean or replace it. Other filters may need expert attention.

Also inspect for gas leaks. Check fittings and couplings for signs of leakage. Tighten parts if needed. My neighbor’s experience serves as a warning, they forgot to do pre-checks and caused a natural gas explosion which injured people and damaged property.

Turning on a Gas Furnace

To turn on your gas furnace, follow these simple steps from Buehler Air Conditioning: locate the gas valve, turn on the furnace switch, light up the pilot light, and adjust the thermostat setting

By carefully completing each of these sub-sections, you can make sure your furnace turns on and heats your home efficiently.

Locate the Gas Valve

To locate the gas valve for your furnace, begin checking the unit itself. Look for a small metal handle near the gas line. If you can’t find it there, check the gas meter outside. 

There should be a shutoff valve on one side. Make sure it’s perpendicular to the pipe before turning it on. Read the instructions for your model of furnace.

Be aware that some valves require an ignition switch or match/lighter. Exercise caution when working with combustible materials. Ventilate your living spaces. If you’re unsure how to start your furnace, call experts in heating services. Follow these steps and you’ll have the gas valve on in no time. Stay informed for safety.

Turn on the Furnace Switch

To activate your gas furnace, you’ll need to turn on its power switch.

Here are the 5 steps you should take:

  1. Locate the switch
  2. Turn it off (if needed)
  3. Set thermostat to “heat”
  4. Reset circuit breaker if necessary
  5. Turn on the switch to activate

Once complete, your furnace is ready to go. But don’t forget to regularly check and maintain it. Safety is key. If you’re unsure about any furnace-related tasks, seek professional help right away. Don’t let the chill keep you from a warm home. Follow these steps and have a cozy winter season.

Light up the Pilot Light

Light up your gas furnace with just six simple steps

  1. Turn off the gas supply valve and wait five minutes. 
  2. Find the pilot assembly and take off its cover. 
  3. Set the gas control knob to ‘pilot’ and press down. 
  4. Use a match or lighter to ignite the pilot orifice. 
  5. Keep pressing the control knob for one minute after ignition. 
  6. Release the knob and make sure the flame remains lit. If not, repeat steps 3-5.

Always prioritize safety when dealing with gas furnaces. Check connections, tubing and burners for leakage or damage. Consult a certified technician to avoid potential hazards.

Adjust Thermostat Setting

  • Calibrate Temperature Regulator: After installing your gas furnace, adjusting the temperature regulator is essential. Ensure the thermostat is calibrated correctly. Follow the manufacturer’s instructions or call a professional service person.
  • Make Necessary Adjustments: Set your ideal temperature level. Wait thirty minutes to see if it heats up. If not, check the air filter and fan settings. Re-adjust the thermostat until you get comfortable indoor temperatures.
  • Ensure Proper Maintenance: Maintain efficiency and safety by scheduling annual maintenance checks. Inspect and fix any faults. This will extend its life and avoid costly repairs.
  • Inspection of Control Valve: Gas furnaces have evolved since David Lennox invented them in 1885. Modern models come with a control valve that regulates fuel flow. Optimize efficiency with this advanced technology.

Troubleshooting a Gas Furnace

To troubleshoot a gas furnace with the steps provided, check the ignition sensor, flame sensor, high limit switch, pressure switch, and capacitor. 

Also, make sure to reset the furnace in case of any malfunctions and check for any smells or leaks to ensure safety. 

Check Ignition Sensor

Turn off the furnace’s power supply before inspecting the ignition sensor. Remove it and clean any dirt or debris with emery cloth or sandpaper. A dirty or faulty sensor can cause shutdowns, or even fail to start. Cleaning may not help, so get a technician if you spot underlying issues.

One homeowner had trouble with his furnace. He tried everything, but the problem stayed until a technician replaced the ignition sensor. Now the furnace works perfectly. A flame sensor that doesn’t sense flames is as useless as a blindfolded traffic cop.

Check Flame Sensor

Check the Flame Sensor to Make Sure Your Gas Furnace Works Properly.

It is essential to inspect the flame sensor every six months to maintain its condition. Here’s how:

  1. Switch off the power first.
  2. Find the flame sensor in the furnace
  3. Clean it with a brush or cloth.
  4. If cleaning doesn’t help, replace it.
  5. Reattach any parts you removed for inspecting.
  6. Turn the power back on and see if the furnace works

If you haven’t inspected the flame sensor in a long time, contact an HVAC specialist. Don’t wait until winter starts, take action now to prevent freezing, chilly nights.

Check High Limit Switch

Verifying if the high-limit switch is operating correctly is essential for a functioning gas furnace. This safety feature prevents overheating and damage to furniture components.

Check the high-limit switch with the following table:

ProblemPossible CauseSolution
Furnace starts but quickly shuts off.High limit switch tripped due to excessive heat buildup.Check air filter, blower motor, and proper venting.
Furnace fails to ignite or run properly.Faulty high limit switch preventing burners from turning on.Test high limit switch for continuity or replace it.

Remember that high-limit switches can get worn out due to heating cycles and need to be replaced. Don’t ignore safety features like the high-limit switch. It could lead to fire hazards, carbon monoxide poisoning, and severe furnace damage.

Make sure to regularly check other components too such as gas pressure, thermostat operations, igniter systems, pilot lights, and flame sensors.

Check Pressure Switch

Examining gas furnace performance is key. We must check the pressure switch to see if it is operational and efficient.

Check for loose electrical connections too. Test continuity across its contacts by testing voltage outputs between terminals. 

Remember, most gas furnaces draw on temperature sensors located after heat exchangers’ exhaust flue pipes. This deactivates the unit’s functions during overheating. Pressure Switches were invented by Willis Carrier in 1930. Many improvements have been made since then.

Check Capacitor

If your gas furnace stops working, it could be due to a malfunctioning capacitor. To check if the capacitor is in good condition, turn off the electricity supply and be safe. Disconnect the terminals from the capacitor and use a multimeter with microfarad setting to check its capacitance. A good capacitor should have same capacitance as stated on it. If it is defective, replace it as per instructions.

However, the motor might still run even if the capacitor goes bad. If more problems arise or no issues are found on checking, call a professional for troubleshooting.

Capacitors can sometimes explode under normal working conditions, leading to severe damage and fire risks. Don’t attempt a repair if you’re not experienced in handling electrical appliances. Also, you may find that replacing the faulty part doesn’t fix the problem,  there could be an underlying issue costing more money and time in repairs. Push the reset button and hope it works.

Reset Button

To get your heating appliance back on track after a furnace power interruption, you’ll need to use the Furnace Reset Button. Here’s how:

  1. Find the reset button on your furnace
  2. Turn off the power
  3. Wait at least 30 secs before switching the power back on
  4. Press and hold the button for 3 secs
  5. When done, release the button and turn the furnace back on.

If you find yourself needing to reset often or it doesn’t work at all, get an HVAC specialist in. It’s a good idea to keep this guide close by too, so others in your home know where the Reset Button is.

Remember that resetting the furnace can help with minor malfunctions or wear and tear, but it’s still best to avoid a gas leak.

Check for Any Smell or Leaks

When you start up a gas furnace, it’s important to check for any strange smells or potential leaks. Not doing so can be really dangerous and put people at risk. 

Here are four things to look out for:

  1. Check the gas valve for any damage that could cause a gas leak.
  2. Examine all the connections to see if any of them are loose and leaking gases.
  3. Make sure the furnace’s vent pipe isn’t blocked or stopped up, so air can get out.
  4. If there are still gas leaks after you do these steps, call a professional right away and don’t use the furnace until they get there.

Be aware that natural gas has a rotten egg stink. A faint smell of dust means something else, but it’s still important to pay attention.

My friend once had a bad experience with his furnace. He smelled something weird, but he kept using it anyway. A few hours later, an alarm went off due to bad ventilation. He got really sick. Don’t be like my friend, always put safety first. Taking good care of your gas furnace is key to keeping it running and your home warm this winter.

Maintenance for a Gas Furnace

To keep your gas furnace working efficiently, you need to perform regular maintenance. In this section, we will go through some essential maintenance tasks for a gas furnace along with some sub-sections. 

These sub-sections include cleaning and replacing filters, cleaning the components of the furnace, inspecting the heat exchanger, checking safety devices, and checking the blower motor and gas flow. By following the instructions for each sub-section regularly, you can ensure that your furnace stays in top condition, and you’ll avoid any potential safety hazards.

Cleaning and Replacing Filters

Filters must be cleaned or replaced each month to get rid of the build-up of dirt and particles. The cleaning method depends on the type of filter, but most standard ones can be washed with water, left to air-dry, and then put back in.

If it’s disposable, remove and dispose of it correctly prior to fitting a replacement.

A blocked or dirty filter reduces the airflow, which leads to your furnace overworking, resulting in its life expectancy being shortened due to overheating.

When picking a new filter, ensure the size fits your existing one for best performance.

To prevent any accidents, always turn off your gas furnace while cleaning. Give it a good scrub and you’ll enjoy warm hugs all winter.

Cleaning the Components of Furnace

The cleanliness of the gas furnace components is essential to keep it running smoothly and economically. Ignoring maintenance can cause blocked or dirty filters, reducing airflow and increasing energy use. 

Here’s how to clean the parts:

  1. Turn off the gas supply before beginning.
  2. Change the air filter every two months for better efficiency.
  3. Clean the blower assembly with a soft brush to remove dirt and debris. Remember to oil the ports that require it.
  4. Wipe all surfaces in the combustion chamber, such as burners, flame sensors and ignitors, with a soft-bristled brush.
  5. Clean exterior surfaces with a damp cloth.

Test your unit after cleaning. If anything looks odd, call an expert. Vacuum around the unit, change thermostat batteries yearly, and arrange for annual inspections by licensed technicians, to maintain your gas furnace.

Inspecting the Heat Exchanger

Conducting gas furnace maintenance? Check the heat exchanger. It’s the device that regulates the heating process. Inspect for visible cracks or damage, and do a carbon monoxide test to make sure exhaust gases are flowing correctly.

A damaged heat exchanger could be dangerous. It could release harmful levels of carbon monoxide, so make sure it is properly repaired before use.

Replacing damaged equipment, like the heat exchanger when necessary is key. This prevents breakdowns and extends the furnace’s lifespan.

Checking Safety Devices

When it comes to gas furnace safety, it’s essential to routinely check its safety devices.

Here are some key things to remember:

  • Inspect the flame sensor for corrosion or damage
  • Check the limit switch for proper operation and setting
  • Examine the draft inducer motor and vent pipe for blockages/obstructions
  • Test the carbon monoxide detectors for proper function

It’s best to have a licensed HVAC professional do these safety device checks. Also, always follow the manufacturer’s instructions when inspecting or maintaining your gas furnace.

Safety is paramount when it comes to your gas furnace. Don’t forget to do regular maintenance checks to prevent any potential danger. Don’t risk your family’s safety and your wallet by neglecting your gas furnace. 

Checking the Blower Motor and Gas Flow

To keep everything running smoothly, it’s essential to inspect both the motor and gas stream. 

Here’s how:

  1. Switch off the furnace and check if the front panel screws are in good condition.
  2. Open the blower compartment. Look at the wheel, motor and belt, if any.
  3. Lubricate the moving parts with lightweight oil if needed.
  4. See if there is any dust or rust build-up on the burner. Clear with air compressor or wire brush.
  5. Check all connections for gas leaks using soapy water.
  6. If you’re unsure, contact a pro technician.

Don’t forget to inspect wiring and filters regularly. A blocked filter may result in poor heating. Overheating may also cause the unit to switch off.

When to Call a Professional Furnace Technician

To ensure that your furnace operates effectively and safely, it’s essential to know when to call a professional furnace technician. 

If your furnace fails to ignite, produces insufficient heat, or requires a repair or replacement, calling in a professional is necessary. 

Furnace maintenance and service are also crucial to ensure optimal performance, efficient heating, and indoor air quality. 

If the Furnace Fails to Ignite

When the Heating System Continues to Be Inactive, it could cause problems like bad air quality and higher energy bills. Home or business owners may try to fix it themselves, but if they can’t, they should call a professional furnace technician. 

Here’s what to do:

  1. Check the energy source.
  2. Look for airflow indicator lights.
  3. Check temperature controls and settings.
  4. Replace old air filters.
  5. Bleed air from radiators/ventilation ducts.
  6. Contact expert HVAC technicians.

Replacing old components and cleaning ventilation channels can help keep the machine running well. Overhauling the whole unit is only worth it if there’s proof it’ll be effective in the long run.

In winter, it’s important to get regular maintenance checkups with your furnace maintenance company. I learned this lesson the hard way one December night when my family was stuck with no heat, even though we’d booked a handyman week prior. We realized that proper maintenance prevents emergencies like this.

If your furnace has become an ice sculpture, it’s time to call the pros.

If the Furnace Fails to Produce Heat

When your heating system isn’t working, it is vital to act quickly to identify and fix the issue. First, make sure that your thermostat is programmed correctly. Second, check if your furnace filters need replacing as poor airflow often causes heating system breakdowns. Third, look at the circuit breaker panel for tripped switches. Lastly, if nothing works, contact a certified technician right away.

It’s important to note that even after following these steps or if you notice small issues, it’s fine to get professional help. They will pinpoint which part of your unit requires fixing or replacing.

Always seek assistance from qualified technicians as incorrect installation of new parts can lead to energy inefficiency and safety risks.If your furnace is older than your teenager and frequently malfunctioning, it’s time to talk to a professional technician about repair or replacement options.

For Furnace Repair or Replacement

If your furnace isn’t working properly, it’s essential to know when to call a pro. Here are some tips:

  • Listen for strange noises or smells.
  • Check if the pilot light is flickering or off.
  • If your furnace is older than 15 years, consider replacing it.

Be aware of warning signs like sudden temperature changes and high utility bills.

For optimal performance and longevity, get a professional maintenance check every year. Before calling in experts, check for simple issues like a wrong thermostat setting or tripped circuit breaker. Changing air filters and cleaning ductwork regularly will help cut repair costs.

Find an HVAC expert with online reviews about experience, ratings and emergency services. Ask for estimates before any work starts. 

For Furnace Maintenance and Service

Is your furnace in need of maintenance or service? Here’s a quick guide to help you know when to call a professional technician.

Listen for strange soundsCheck your energy billsLook out for strange smellsInspect for wear and tear
Banging, whistling or hissing could mean it’s time to get help.A sudden rise could indicate decreased efficiency.Burning or rotten egg smell means it’s time to call for help.An expert can spot signs that need attention.

Regular maintenance is vital for keeping your furnace running efficiently. Don’t hesitate to get professional support.

One homeowner ignored the noise coming from his furnace, only to find he had no heat when temperatures dropped to freezing at night. Don’t play with fire, get help for your gas furnace.

Safety Tips When Turning on a Gas Furnace

To ensure your safety when turning on a gas furnace with the sub-sections of 

  • check for gas fumes, 
  • keep the area well-ventilated, 
  • turn off gas and electricity in case of emergencies, 
  • avoid using matches or lighters, and 
  • contact an HVAC pro when in doubt

Though it may seem like a simple matter, turning on a gas furnace can be dangerous if proper precautions are not taken. 

Check for Gas Fumes

Check for gas leaks before turning on the furnace. Check connections between main gas line and furnace. Look for corroded pipes. Sniff out the air around the furnace as sulfur or rotten eggs smell could indicate a leak. 

Don’t store flammable materials near furnace. Sparks can cause explosions if certain chemicals come into contact with open flames.

Maxine’s family had a cold winter morning incident. They reported a strong odor when they turned on heating unit. Gas leak was discovered. Quick action by technicians prevented injuries. Open windows, but be careful not to let birds fly in.

Keep the Area Well-Ventilated

To stay safe, proper ventilation is a must for gas furnaces. Too much carbon monoxide can cause serious health issues or death. Increase air flow by opening windows and doors near the furnace. 

Don’t forget to clean and replace air filters often. Check any vents outside for any blockages or debris that could stop the air from flowing. Remember, no proper ventilation, no safe operation of your gas furnace. reminds us that too little ventilation can result in dangerous levels of carbon monoxide in your home. Always be cautious and in an emergency, turn off electricity and gas – you don’t want your furnace to become a firestarter.

Turn Off Gas and Electricity in Case of Emergencies

In emergencies, it’s important to turn off your gas & electricity. 

Here’s how:

1. GasLocate the shut-off valve near your gas meter outside. Turn it clockwise to close.
2. ElectricityFind your home’s main electrical panel or breaker box. Flip the main circuit breaker switch to OFF.
3. WaterShut off your home’s water supply through the main water valve usually found behind a washing machine or toilet.

Take precautions to prevent accidents & save lives. Have emergency supplies (flashlights, extra batteries) ready in case of power outages during natural disasters or other unexpected events.

Don’t use matches or lighters. A family in our community once forgot to turn off their gas during a storm, resulting in a gas leak & explosion damaging their home & injuring them. So, always take precautions.

Avoid Using Matches or Lighters

When turning on a gas furnace, opt for the ignition switch or pilot light. Reach for a match or lighter and you might have a gas explosion or fire.

Clear the area of anything flammable, like paper or cleaning supplies. Plus, install carbon monoxide detectors in the same room as the furnace and check them regularly.

HVAC technicians can provide regular maintenance and inspections to address potential issues. It’s important because faulty furnaces are a leading cause of carbon monoxide poisoning. The CDC says that 400 Americans die each year from this deadly gas. Follow these safety tips and you can protect yourself and your loved ones.

Contact an HVAC Pro When in Doubt

Seek the help of an expert HVAC technician when safety is a concern for your gas furnace. This is especially true if you notice any leaks, strange smells or noises. They know how to spot problems and make repairs. Ignoring maintenance and repairs can be dangerous and costly.

Plus, a pro can share tips on how to safely handle your furnace, like insulating the vents to keep flammable materials away. Know what signs to look out for on the thermostat and other equipment.

Pro Tip: Don’t forget to check smoke detectors near your furnace. Remember, a little gas can cause a lot of damage if you don’t follow safety tips.


When it comes to turning on a gas furnace, preparation and maintenance are essential. With the right care, it can be straightforward. Read the manufacturer’s instructions for your model. The manual will give detailed info to operate it properly. Check that all components are in good condition. Change the filter regularly, check fuses & circuit breakers, and inspect wiring & connections for damage. Set the thermostat to your desired temp. & switch/ button near the furnace’s ignition to ‘on’. The system should ignite automatically or you may have to manually light it with a match. Furnaces have safety devices like high limit switches, thermocouples, flame sensors & pressure switches to prevent fires in case of a fuel supply issue. Contact HVAC pros who have expertise in repairing heating system components. Don’t attempt repairs if unsure. Schedule routine maintenance by licensed professionals at least once every few months during heating season. Helps identify potential issues & prevents harm or costly damage to your home.