Furnace Maintenance Checklist – 7 Easy Steps

Furnace Maintenance Checklist – 7 Easy Steps

Furnace maintenance is essential for keeping your furnace functioning well. As a homeowner, you can take certain precautions to keep your furnace in good working order.

This article explains how to inspect and Repair Your Furnace to keep it functioning smoothly.

Also check: Are You Wondering Why Do New Furnaces Smell?

Furnace Maintenance Checklist

The maintenance chores listed below should be completed on your AC system at least once a year. The only exception is replacing the air filter. This should be done at least every three months or more frequently if necessary.

  1. Replace Air Filter
  2. Clean burners and flame sensor
  3. Inspect heat exchanger and CO detector
  4. Lubricate blower and inducer fans
  5. Clean humidifier
  6. Inspect electrical wirings and controls
  7. Check thermostat for proper operation

Furnace Air Filter Maintenance

An air filter’s goal is to remove dirt, dust, and other impurities from the air in your home. The filter is positioned in the furnace’s return air duct, where the fan draws air.

The furnace air filter should be updated every three months at the absolute least. It should be updated every 1-2 months. Pleated filters often last a little longer but result in a higher pressure drop in the system. Check to see if your furnace is capable of this. The non-pleated filter only lasts approximately a month but does not significantly restrict airflow. Non-pleated filters are used in many older HVAC systems incapable of handling high-pressure drops.

To begin replacing the furnace air filter, switch off the furnace. Remove the filter access panel from the duct once the furnace has stopped. Then, gently remove the old filter to avoid dust and grime falling off or spreading elsewhere. Remove the old filter and insert the new one into the filter chamber. If the filter includes an arrow, ensure it points in the same direction as the furnace airflow.

Maintenance of a Furnace Burner

A burner is a furnace component that burns gas to produce a flame. The burners are vulnerable to carbon and soot production due to gas combustion. The furnace burner assembly should be inspected regularly to verify that it is clean and functional.

The first step in inspecting furnace burners is to cut off the furnace’s power and gas. Working in live furnaces is not recommended. Then, remove the cover plate to access the furnace’s interior. Once inside the furnace, vacuum the area around the burners to remove any debris. The burner should then be removed and inspected. Examine the front of the burner, where the flame emerges. Brush away rubbish using a brass wire brush.

On the sidewalls of certain burners are “transition vanes.” The flame can flow from burner to burner thanks to this short tube. The transition vanes should be clean and clear of debris as well. All burners may not fire if the transition vanes are clogged.

When working with burners, use caution with the igniter. The two wires connected to the Ignitor identify it. It’s recommended to avoid touching the igniter, especially if it’s a hot surface igniter. It shatters when an igniter with a heated surface is hit or mishandled. If the igniter does not work, it is preferable to replace it rather than to clean or troubleshoot it.

Maintenance of The Furnace Burner Manifold

In the furnace, a burner manifold injects fuel into the burners. A tiny aperture towards the burner allows gas or fuel to exit the manifold. A valve assembly attached to the manifold controls fuel flow.

To prevent blockage, small apertures in burner manifolds must be cleaned. Pierce the gap with a tiny wire or paperclip and scrape away any material.

Cleaning The Furnace Flame Sensor

The flame sensor is another component of maintenance. The flame sensor is a little metal bar in front of one of the burners. Flame protectors are intended to ensure that all burners ignite.

The furnace is turned off if the flame sensor does not detect a flame. Even if all burners are lit, a dirty flame sensor will cause the furnace to shut down. Disconnect and remove the cord to clean the flame sensor. Because it just has one wire, the flame sensor is easily identified. Flame monitors are typically held in place with a single, conveniently accessible screw.

Scrape the metal rod to eliminate char buildup after removing the flame sensor. Various products such as wire brushes, rags, or scouring pads can be used to clean the flame sensor. Take care not to scratch or damage the scanner’s ceramic body. The flame sensor’s ceramic component is delicate and brittle.

After cleaning, replace the flame sensor in the hole and secure it with a screw.

Inspection of The Furnace Heat Exchanger

Most furnace heat exchanger maintenance should be left to specialists, but you can undertake regular inspections to verify that everything is in working order.

The first step is to cut off the furnace’s power and gas. Then, remove the access panel to access the furnace’s mechanical components. Examine the heat exchange cells behind the burners inside the furnace. Examine the vehicle for evidence of damage, excessive rust, or carbon buildup. Examine the heat exchanger fittings for cracks. Remove the burner or fan to better look at the heat exchanger. In the tight places where heat exchangers are positioned, inspection cameras or endoscopes can look for ordinarily unseen cracks.

It will be costly to replace your furnace’s heat exchanger if it is cracked. It is frequently preferable to replace the entire furnace yourself. To discuss your alternatives, speak with a local HVAC professional.

Heat Exchanger Matching Test

The heat exchanger match test is a handy method for detecting cracks in your heat exchanger. By searching for airflow from the heat exchanger fans, the consistency test aids in detecting damaged heat exchangers.

To perform the heat exchanger match test, ensure the furnace is in FAN ONLY mode. Check that the furnace is not in AUTO or HEAT mode. While inspecting the heat exchanger, do not light the burner. Turn off the furnace’s gas supply. Light the matches and place them in front of the heat exchanger cells while the Furnace Fan Is Running. Be cautious of match flames. If the wind blows and stops, there is a crack or hole in the heat exchanger. This test works because the air from the fan blows out the matches through the openings in the heat exchanger.

The Detector of Carbon Monoxide

A faulty heat exchanger is quite hazardous to the residents of your home. If the heat exchanger in your furnace cracks, poisonous Gases Will Leak into the airflow in your home. As a result, if you have a furnace, you must install at least one carbon monoxide (CO) alarm in your home.

For security, while you and your family sleep, install at least one CO alarm on each floor and in each bedroom in your home.

Carbon monoxide alarms do not require the same installation level as smoke alarms. Because CO is heavier than air, it falls to the ground quickly. As a result, the CO detector can be easily wall-mounted.

It is critical to test the CO alarm regularly (at least once a month). Replace the battery in your carbon monoxide detector every six months. Even with periodic battery changes, all CO alarms will need to be replaced. The CO detector sensor lasts approximately 5-7 years.

If you are unclear about the age of your CO alarm, we recommend that you replace it. Make a note of the date you installed the new CO alarm. You’ll be able to tell when a replacement is required this way.

Maintenance of a Furnace Blower

A furnace blower is a fan that circulates air throughout your house. A fan ensures that the heat produced by your furnace is distributed throughout your home.

To service the furnace fan, switch off the furnace’s power. Open the furnace access panel to gain access to the fan.

The first thing to look for is free and smooth fan wheel rotation. The fan motor may wear out and require replacement. Check the condition of the fan blades as well to ensure they are not dusty or broken.

Check the belts and pulleys on your fan as well. Check that the V-belt is in good shape and appropriately tensioned. V-belts normally have a lifespan of around a year. The blower motor should be lubricated regularly. It is critical to keep the fan motor lubricated with oil to work properly. Most older fan motors include oil ports that may be filled with a lubricant such as Liquid Bearing Synthetic Oil.

Because newer fan motors lack oil ports, the oil must be delivered directly to the motor shaft connected to the body.

Furnace Inducer Upkeep

The inducer is a blower that blows the furnace’s combustion gases out of the building. It takes hot combustion gases through the furnace’s heat exchanger and exhausts them outside the house.

A furnace’s induction assembly comprises a fan that blasts air and an electric motor that rotates the fan. The inducer is critical to the operation of the furnace and should be kept in good working order. Turn off the furnace before servicing the inducer. Then, remove the furnace access panel to reveal the inductor.

The first maintenance check is to ensure the safety of the induction motor. Check the engine to see if anything is loose. Grommets are necessary on some inducer motors to keep the inducer secure. The inducer might rattle or Generate Noise if the inducer motor is loose. Cooling blades are used in some induction motors (disks attached to the back of the motor). In such circumstances, rotate the cooling blades and check to see if the motor is freely rotating. If the motor drags or becomes stuck, it is malfunctioning and should be replaced.

If an induction motor becomes stuck, lubricating it will allow it to spin freely again. For this purpose, older induction motors have easy oil ports. Oil ports are typically absent in new induction motors. If your induction motor lacks an oil fitting, you must lubricate the motor shaft with oil so that it may penetrate the motor.

Getting an induction motor greased and functioning is usually only a short-term solution. If the inducer is dragging or binding, replace the entire inducer assembly as soon as feasible.

The bleed port, often known as the bleed boot, connects the fan to the exhaust port. The bleeder sleeve should be tightened and secured at all times. A breather boot leak might allow dangerous combustion gases into your home.

Furnace Humidifier Upkeep

Your HVAC system may incorporate a humidifier in dry locations to help keep your home pleasant and humid. A humidifier aims to add moisture to the air. Moderate humidity is required for a comfortable interior environment. In addition, adequate humidity protects against dry skin, allergies, and respiratory difficulties.

Also check: Can You Use Patio Heaters Indoors?

Furnace Electrical and Controls Upkeep

A well-functioning furnace includes an electrical and control system. While electrical maintenance should normally be left to specialists, there are some things you can do to keep your furnace in good working order.

Before working on the furnace’s electrical system, turn off all electricity to the furnace. Then, open the access panel for the electrical and control wiring in the furnace. The first thing to look for is whether all connections are firm or tight. Poor electrical links can lead to erratic behavior and even fires, so check for loose wires and rusted connectors.

Then, clean the electrical enclosure area using compressed air or canned air, such as Dust-off. Ensure that the electrical components and cables are nice, clean, and free of dirt and bugs. Excessive land surrounding electrical equipment can create short circuits and damage the device. After cleaning the furnace’s electrical system, replace the access panel and turn on the stove.

Testing of the Furnace Thermostat

Check the thermostat on your furnace for optimal operation. Check that all fan speeds are operational when utilizing multi-speed fans. Check the operation of the valves and dampers.

Use a portable temperature sensor to check that your thermostat is reading the right temperature. The thermostat should show the same temperature as the temperature sensor (within 1 degree Fahrenheit or 0.5 degrees Celsius). If your furnace has a schedule, ensure it’s set for the time and day of the week when you’re generally home. Also, test the program to ensure that the Furnace Turns On And Off as it should.

If you have any additional electrical or control concerns with your furnace, we recommend visiting an HVAC professional.


To extend the life of your furnace, schedule routine maintenance and inspections. Preventative maintenance lets you become acquainted with your furnace system and thus better understand how everything functions. Knowing how everything works will allow you to make better decisions about when to call a professional.


How often should a furnace be serviced?

According to most engineers, furniture should be maintained at least once a year. Some people procrastinate on maintenance until it is too late. Small cavities might become major issues if you don’t see a dentist every six months.

What exactly is a furnace tune-up?

Gas calibration and furnace burner cleaning and maintenance are part of the furnace setup to ensure proper temperature output. This ensures safe operation and maintains your furnace running at peak efficiency throughout the season.

Do you require a furnace installation?

Yes! If the manufacturer’s warranty covers your furnace, you should plan for furnace adjustments. Most furnace manufacturers recommend annual maintenance by a competent HVAC expert, and damage caused by incorrect care is not covered under warranty.

How much does it cost to have the furnace cleaned?

The cost of cleaning a furnace ranges between $50 and $300. The actual cost is determined by the state of your furnace and the quantity of maintenance and servicing required to clean it. Fan cleaning is usually included in furnace cleaning.


About Author

Gulzar Abid

Gulzar Abid

Gulzar Abid is a passionate entrepreneur with a thirst for knowledge and yearns to help empower people to initiate their journey of growth and success. Chief Executive Officer K2 Groups Chief Executive Officer K2 Heating & Air Conditioning

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