9 Common Problems to Help You Troubleshoot Your Furnace

    A furnace is vital for comfort and survival in the chilly winter months. However, nothing is worse than waking up cold in the middle of the night due to a furnace that isn’t operating properly. Furnaces may malfunction and develop issues that prevent normal operation, even with routine maintenance.

    While you should have your furnace fixed as soon as it breaks down, there are several signs you can watch for to identify problems early and avoid paying extra for a furnace repair or replacement. The most frequent furnace issues are highlighted below.

    1. Faulty Thermostat

    A dysfunctional thermostat is one of the most frequent furnace issues homeowners encounter. This gadget assesses your home’s heating requirements and alerts the furnace whether to turn on or off. If your fan runs continuously, your thermostat is probably not functioning correctly. As a result, your furnace generates more or less heat than is necessary.

    When this occurs, you should start by ensuring the thermostat is in the heat setting, which is above five degrees warmer than the room temperature. You can also swap out the thermostat batteries if this doesn’t fix the problem, or open the thermostat and clean out the debris.

    2. The Furnace Doesn’t Blow Warm Air

    The furnace may sometimes fail to provide warm air everywhere in the home after being turned on. When this happens, you may start by cleaning away any debris since a blocked blower may be the source of this issue. Additionally, the furnace won’t blow warm air if your thermostat is set to the fan position; therefore, it’s crucial to change it.

    Other times, a tripped circuit breaker or a blown fuse might cause your furnace’s inability to blow warm air. The circuit breaker may be flipped back to reset the furnace if you have expertise working with electrical components.

    3. Unclean Air Filters.

    A furnace filter captures allergens like pollen, pet dander, and grime from the interior air. When disregarded, these contaminants may block air filters and reduce airflow. Thus, to maintain the correct inside temperature, the furnace will need to operate more vigorously, placing stress on essential parts and using more energy.

    Also, your limit switch can end up being hurt as a result. Cleaning or replacing the air filters every three months can guarantee top efficiency and help prevent such problems.

    4. Pilot Light or Electrical Ignition Issues

    Pilot light or ignition issues impair the furnace’s capacity to heat the home appropriately and are more likely to occur with older furnaces. The pilot light might turn off due to dirt build-up in the heating system. The fuel won’t ignite in this case, and the furnace cannot generate heat. The furnace also won’t create warm air if it has a flaw. Additionally, a high level of carbon monoxide in your gas furnace may cause the pilot light to flicker or become yellow.

    5. Frequent and Over-Cycling

    Frequent cycles in your furnace are another potential issue. As a result, your unit will switch off even before the home reaches the desired temperature. Also, restricted airflow is the primary reason for short cycles. You may fix this issue by removing impediments obstructing heat flow around the vents.

    You may also check the thermostat setting and look for obstructions in the air filter. The furnace may also overheat from repeated cycles, but most models include safety measures that turn the system off when the temperature rises too high. It’s crucial to rectify the issue as soon as possible since frequent cycles also lead to higher electricity expenditures.

    6. Unusual and Loud Noises

    When you hear odd noises from your furnace, it implies that certain components are broken and need repair. If your appliance makes banging or popping noises, it’s because the burner can’t get hot enough to burn the fuel.

    The ductwork also makes banging noises when the furnace shuts off as it expands and contracts due to temperature fluctuations. Humming or buzzing noises indicate loose parts. Noises that rattle or ratchet might be loose ductwork, debris, or a damaged fan blade. A continuous vibration from your furnace indicates that the air filters are blocked.

    7. Worn Out Ball Bearings

    The ball bearings in your furnace make the motor function correctly. Unfortunately, they sometimes need to be replaced because of wear and tear over time. Your furnace should be turned off right away if you hear scraping noises coming from it. Also, you can refer to a furnace repair guide to help you troubleshoot further issues.

    8. Cracks in the Heat Exchanger

    A fractured heat exchanger compromises your furnace’s capacity to operate at its best. Additionally, it permits the buildup of carbon monoxide within your home. If you overheat your house or disregard your air filters, the heat exchanger is more prone to break.

    Cracked heat exchangers often exhibit the following symptoms:

    • Your furnace’s inside is covered with soot.
    • A pungent smell.
    • There is water on the ground around the furnace.
    • People in your household exhibit flu-like symptoms, nausea, headaches, inflamed eyes, or other signs of carbon monoxide poisoning.

    Unfortunately, to solve this issue, you must replace the heat exchanger.

    9. Dripping Water

    High-efficiency furnaces create condensation by collecting vapor from the combustion gases in the heat exchanger. Such furnaces may have leak issues, and you can start to see water accumulating under the apparatus.

    The major cause of these leaks is an obstructed condensation line. Additionally, a break might result in water leakage if your furnace is attached to a whole-house dehumidifier. You may get in touch with a qualified technician to identify the root of the issue and resolve it.


    The lifetime of a well-maintained furnace is longer, but it is not indefinite. After some time, furnaces experience natural wear and tear, which might cause a frustrating mechanical failure. You’ll understand your furnace better if you know the most typical issues they encounter.

    Additionally, you are better able to recognize problematic symptoms and quickly seek expert assistance. By having your furnace checked out regularly, a technician may see a minor issue and correct it before it grows into a significant one, helping to prevent most problems.

    The Zigverve Team
    The Zigverve Team
    The dedicated team at Zigverve that aims at bringing you the best lifestyle updates from all over the world.

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