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Every homeowner should know some basic furnace troubleshooting skills. This is especially important during the cold months when there is more demand for the furnace to work harder. Although furnaces are quite sturdy, they are also vulnerable to damage. Over time, your reliable furnace system will begin to show problems that will negatively impact your safety and comfort. Of course, you can always turn to an HVAC professional for every problem that comes up. However, there are actually basic troubleshooting steps you can do at home that will keep your furnace in good shape.

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Troubleshooting Tips For Your Furnace

We believe that every homeowner should have a set of necessary skills to help them identify problems with their furnace. In this article, we share some basic furnace troubleshooting tips that all homeowners should be aware of.

Furnace Maintenance

Furnaces work the hardest during the fall and winter months. If the furnace does not receive a regular furnace checkup, it will break down prematurely and give in to component damage and early wear-and-tear. This can be avoided with regular heating system maintenance. It is fairly simple, actually. Working with a trusted HVAC company, you can prevent serious furnace damage with annual furnace tune-ups, gas furnace troubleshooting, and repairs where and when required. Do not delay attention to any issue that your furnace may exhibit. If you wait until the problem turns serious, you may have to deal with irreparable and/or more expensive issues.

Furnace troubleshooting tip: Call your HVAC company to schedule annual maintenance. Call for furnace repairs when your furnace is underperforming.

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Dirty HVAC Air Filters

If you have a forced-air furnace, one of the most common issues you will encounter is a clogged furnace air filter. The air filter collects particulates and pollutants present in the air. It helps control how much dust, dirt, and pollen are present indoors. However, air filters do become clogged over time. When this happens, they become less efficient and effective. Neglecting a furnace filter replacement can also lead to more serious issues and even premature replacement.

Furnace troubleshooting tip: Perform a visual checkup of the filter monthly. If it is already clogged or dirty, take it out and clean it or have it replaced.


Heater Pilot Control Or Furnace Electric Ignition Issues

If your furnace shows an electric ignition problem, it may be caused by an electrical issue. Your furnace requires a working pilot. If it is out, the system will not produce heat. If you have an electronic igniter, do not attempt to light it manually. Check if your furnace is powered up and read the owner’s manual before re-lighting the igniter.

Furnace troubleshooting tip: Check if the circuit breaker is tripped, then check the unit. If your furnace still does not work, call your HVAC contractor for service.

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Malfunctioning Thermostat

When you turn on your furnace, the thermostat turns on with it. If it fails to do so, it may be damaged or faulty. Thankfully, troubleshooting a faulty thermostat is fairly easy and having it upgraded or replaced is not a serious expense. If temperature readings are not visible, you may have to replace the batteries on the thermostat.

Furnace troubleshooting tip: Turn the furnace switch off, then on again to reset the thermostat. You could also shut down the power completely. If batteries are the issue, replace them. If, after all these steps, the thermostat still fails to work, get in touch with a licensed HVAC technician and have the unit inspected.

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Furnace Produces Cold Air

When your furnace starts blowing cool air, the problem may be traced to several sources. These include: a clogged filter, no power or gas, or the wrong temperature setting. It could also be that the pilot light has gone out. Another reason is furnace sizing. If your furnace is the wrong size for your home, it may not be effective in keeping your indoor environment warm.

Furnace troubleshooting tip: Clean the filter or have it replaced, check the fuel level or power source, set the thermostat at the proper setting, and see if the pilot light is on. If you suspect that the capacity of your furnace is wrong, call your HVAC company for an inspection.

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Frequent Heating System Cycling

Short or frequent cycling is a malfunction characterized by the furnace switching on and off within quick succession. The short but constant activity burst can point to several issues, such as improper furnace sizing, faulty temperature reading, overheating, or dirty air filters.

Furnace troubleshooting tip: First, check your thermostat for damage and other issues. If your thermostat is located in an area of the home where it is exposed for several hours to direct sunlight or heat, consider relocating it or using a shield to create a buffer between the thermostat and the light/heat source. Have your furnace checked if it is the correct size or capacity for your home? You might also ask your HVAC contractor to check if your heat exchanger is damaged since this is a common cause of short cycling.

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Furnace Blower Continuously Runs

Normally, the furnace blower does not run continuously. If it does, the limit switch might be damaged or there might be a problem with the setting. Also, if your furnace unit has a manual fan limit switch, check to see if it is at the manual position. If it is, change it to the automatic setting.

Furnace troubleshooting tip: Turn the limit switch to automatic setting. This will prevent the fan from blowing continuously. However, if the limit switch is damaged, make sure to have an HVAC technician inspect the unit.

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Furnace Produces Unusual Odors And Noises

A furnace operating normally is not likely to produce unusual sounds. If you hear clicking, clanking, screeching, and booming noises, there is likely a problem with the system. The same is true if the furnace produces an unusual or unpleasant smell.

Furnace troubleshooting tip: Check to see if the airflow is the problem. If the airflow is blocked, remove the obstruction. Check the filters as well. Very often, heavily clogged air filters accumulate enough debris to start producing an unusual odor. If the problem turns out to be mechanical, such as if there is a damaged or loose component, call a professional and do not try to make the repairs on your own.

Call Hart Home Comfort For All Of Your Home Heating Needs


There are times when problems with your furnace cannot and should not be fixed with basic troubleshooting, even if you can do it safely. Whether or not you can troubleshoot, it is still important that you learn how your furnace works so you know exactly what to expect from it and how to best care for it.

However, when you need the experts to come in and take care of your furnace system, call Hart Home Comfort. We are the leading heating and cooling providers in the region. We offer a range of services from HVAC tune-ups and installations, to repairs and replacements. Our NATE certified heating and cooling technicians ensure that they provide topnotch quality service to our clients.

We understand the importance of comfort and safety in your home. At Hart Home Comfort, we want our clients to feel the assurance that we can guarantee through our services. We offer the most competitive costs in the area and ensure that our services provide you with comfort, safety, high-quality indoor air, and improved energy efficiency. Schedule a free, in-home estimate with us today.

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For any questions about what Hart Home Comfort can do for you, give us a call today. Click here to contact us now or call us at (631) 667-3200 to find out more!