Skip to content

Staying Smart about Heating: 7 Common Furnace Problems in Oswego, Yorkville, Naperville, Aurora and Plainfield

Most of us usually want to know how to respond to a problem that can’t be overlooked for long, especially when it involves what we depend on at home or in the office in Oswego, Yorkville, Naperville, Aurora or Plainfield.

With HVAC, there are definitely times when your comfort and safety will best be served by consulting a professional. However, with a little bit of knowledge, you can begin to pinpoint some issues yourself if not straightaway fix them.

We depend on our furnaces more than ever during the winter. If you notice yours might not be working properly, the following are seven common problems that could be a reason. Reviewing them will help you know what to consider and what to do about erratic or malfunctioning heating, as well as what you might do to help prevent it.

Air Filter

A regular cause of compromised heating is the filter. Filters clean both the air moving into the furnace and the heated air it returns. Leaving in the same filter too long let excess dust build on it. This can strain the unit, restrict airflow and even make the furnace shut off.

If the furnace turns on but doesn’t blow consistently, check the filter. On the average, it should be replaced at least every three months. Also be sure the directional arrows on it are pointing in the right direction; otherwise, the filter may not perform as it should.


Another contributor to improper heating can be the thermostat. You’d be surprised by how often Air Dynamics technicians have found this to be the issue during a service visit.

If the thermostat runs on a battery, make sure it doesn’t need a new one. If the battery is good and your furnace still isn’t working right, make sure the thermostat is set on “heat” and above the current room temperature.

You might also want to open the thermostat and gently blow any dust or debris that may have collected in it. If the thermostat is programmable or on a timer, check that the date and time are correct as well.

Circuit Breaker

Some heating problems originate with the circuit breaker. Every once in a while something can make it trip, cutting off the power supply.

If you know the air filter is still current and the thermostat works, check your fuse box. Locate the fuse that controls the furnace and see if it is in the “off” position. Flipping it back to “on” will reset the breaker.

(Another thing to check is the switch next to the fuse box if there is one. It looks like a light switch. Sometimes it can be turned off by mistake.)

If the furnace still does not turn on or receive power, you might have an issue with the circuit wiring or the circuit itself. In this case, be sure to contact an electrician right away.


Today’s gas furnaces no longer use standing pilot lights as older models once did. Rather, they apply either intermittent or hot-surface ignition with electronic control to activate the unit.

With older gas units, something as simple as a draft or a system clog can blow out the light. Newer systems are typically efficient and reliable, but like anything else they won’t always be perfect. A part can break or wear out, or a safety switch can malfunction.

If you detect or troubleshoot an ignition problem, you can try turning the furnace on and off to reset the ignition. If the ignition still isn’t working, consult a heating professional.


Once a furnace is activated, it depends on a burner to heat the air that travels through the ducts to your rooms. In some cases, the ignition system is fine but the burner doesn’t light. Other times, the burner itself just isn’t working, which will affect your heating.

If after considering the other factors we’ve discussed you think you might still have a furnace issue, start with a visual check of the burners. Sometimes dust, soot and condensation will accumulate on them over time. Clean burners will have blue, even flames. Yellow flames are signs of dirty burners.

In proper practice, the burners should be cleaned each year, particularly before the cold season. To do this, first ensure the power and the gas to the furnace are off. Then use a vacuum cleaner to clean the burners and the area around them.

If still have issues with the burners, or if you prefer that a specialist clean them for you, consult a heating professional.


Located between the return ductwork and the furnace, the blower draws heat from the furnace and distributes it through your home or office. If the blower has a problem, many times it’s because of the blower belt. One sign of a bad blower is a high-pitched sound from either the belt or the blower itself. Another is a furnace that constantly runs and doesn’t turn off.

Should you suspect a blower or blower belt problem, start by making sure the thermostat is set on “auto” and not “continuous fan.” You might look through the furnace’s inspection window as well; the blower should be clear of debris. Some furnaces also have a colored LED light that flashes a code indicating if service is needed.

Heat Exchanger

The heat exchanger separates the warming flame of the furnace from the air in the home or office. In the case of units that burn a fossil fuel such as propane or natural gas, the heat exchanger contains harmful fumes (e.g. carbon dioxide or monoxide) while transferring the safe, usable heat into spaces. If the heat exchanger is cracked or otherwise compromised, it can release the dangerous fumes and create a hazard.

Signs that the heat exchanger might be cracked can be a yellow flame that flickers more often; stress cracks or corrosion in other parts of the furnace; build-up of soot inside the unit; and strong or unpleasant odors, which are released by the toxic fumes. Also be aware of flu-like symptoms that lessen away from the home or office.

Contact Us Today

A little bit of smarts about heating goes a long way. When it gets cold out, your warmth and comfort and especially your safety are important. If you would ever like more advice or information about common furnace problems in Oswego, Yorkville, Naperville, Aurora or Plainfield, call us anytime at (630) 731-1550. We’re here to serve and support you!

Air Dynamics Heating & Cooling

Install Air Dynamics Heating & Cooling

Install this application on your home screen for quick and easy access when you’re on the go.

Just tap then “Add to Home Screen”

Accessibility Toolbar