7 Common Furnace Problems (and How to Fix Them Fast!)


    For many of us, winter is our favorite time of year. That winter chill in the air sparks a warm nostalgia for years gone by. But when you go inside to get warm and Jack Frost is still nipping at your nose, that’s no fun for anyone.

    Furnace problems can turn the most wonderful time of the year into an unbearable scourge. Fortunately, we can tell you what to do about them.

    Below are 7 of the most common furnace problems and what you can do about them. So, if your furnace is broken, wrap yourself up in a blanket or two and then try these tips.

    1. There Is No Heat Coming From the Vents

    There are lots of reasons why little-to-no heat is coming from your vents. The first thing you should check is your thermostat.

    Checking the Thermostat

    Check that it’s turned on and set to heat. If air is blowing but it’s not hot, your thermostat might simply have the fan set in the “On” position. Adjust the temperature setting high enough so that the heat should activate.

    Changing the Air Filter

    If all the settings are correct and the air from the vents still isn’t warm, check the air filter. A clogged filter might be blocking the heat from your furnace so that it can’t reach the rooms of your house. Change your air filter at least every 3 months.

    Relighting the Pilot Light

    If you have a very old furnace, it probably uses a pilot light to ignite the fuel to heat the house. If this light gets blown out, you must relight it in order to produce heat.

    Similarly, newer models use an electronic ignition system to light the pilot. If your igniter is broken, you’ll need to have it replaced by professionals.

    1. The Blower Runs Constantly

    Perhaps you have air blowing out of your vents constantly. We touched on one possible cause of this already.

    Check if your thermostat’s fan setting is switched to “On” instead of “Auto.” If it’s in the “On” setting, it will keep blowing air all the time, whether it’s heated or not. If switching to “Auto” doesn’t work, you may need to replace your thermostat or call for professional help.

    It’s also possible that your home isn’t insulated well and your furnace must stay on to keep your home at the desired temperature.  Alternatively, other furnace problems, like insufficient heat or airflow, could make it impossible for your furnace to warm your home to the desired temperature. In this case, the furnace just stays on, trying to reach the set temperature but unable to do so.

    If the troubleshooting steps on this list doesn’t solve the problem, contact a reliable HVAC repair company, like Schneider Mechanical.

    1. The Furnace Is Constantly Turning On and Off

    Does your furnace keep switching on and off in short cycles? Usually, this is due to your furnace’s automatic safety shutoff feature.

    In the event of overheating, most furnaces automatically shut off to prevent fires. A clogged filter is the most likely cause of an overheating furnace.

    Check the filter and replace it if necessary. Then, try your furnace again.

    If this doesn’t work, shut your furnace off and call for emergency furnace repair. There could be some other dangerous situation that keeps triggering the auto-shutoff.

    1. The Furnace Won’t Turn On By Itself

    The auto-shutoff might also be to blame when the furnace isn’t turning on when it’s supposed to. But check your thermostat first.

    Make sure all the settings are correct and test any features you can to make sure it’s working. For example, set your AC to come on instead and see if it turns on automatically like it’s supposed to. If it’s not working, your thermostat might need replacing.

    Or perhaps the circuit is switched off. Check your circuit breaker and make sure that the relevant circuit is switched on.

    If both the circuit and the thermostat are working, check your air filter and your pilot light. It might also be that your furnace has no fuel.

    If it’s a gas furnace, call the gas company to make sure the gas is turned on. Call a professional HVAC technician if all else fails.

    1. The Furnace Won’t Turn On At All

    Is your furnace not coming on at all? For the most part, troubleshooting this problem is the same as in the previous step. There may, however, be one more safety feature to blame, here: an open access panel.

    There’s a door that must be opened in order to access the inner workings of your furnace. If this door is open, even slightly ajar, it may trigger the auto-shutoff. Try opening and closing this door tight and see if that helps.

    1. The Furnace Is Very Noisy

    Strange, loud noises from your furnace are always a bad sign. For example, a loud squealing probably indicates a worn-out blower belt. If you’re comfortable doing so, you can probably buy a new belt and put it in yourself.

    A loud scraping or grinding noise could mean that the ball bearings in the blower are worn out. Clanking, knocking, or rattling could indicate a loose component. Either of these means you should call for professional repair before the damage gets really bad.

    On the other hand, one or two loud bangs or pops when your furnace starts probably aren’t a big deal. This is usually just your ducts expanding from the heat of the furnace.

    1. Puddles of Water Around Your Furnace

    Pools of water around your furnace are usually just condensation. Still, the condensation should be draining, not collecting on the ground.

    Check the condensation drain for clogs and unclog it if possible. Otherwise, call a professional HVAC technician to come and take a look at it.

    Solve Your Furnace Problems With This Guide

    If you experience any furnace problems in the future, remember this guide. And, please, share this guide with others so they can keep warm this winter, too.

    What would you like to learn about next? No matter what topic you’re interested in, we have a blog post about it. Use the search bar in the top-right corner of this page to find any topic you’re looking for.