Homeowners in Oswego, Yorkville, Naperville, Aurora and Plainfield (IL) know how charming fall in the region can be. The outdoor temperatures have been mild this year as well, making it even easier to go for a walk, sit outside and keep the house windows open without too much extra thought about home heating.
As we all know, even favorable weather will eventually make its drop here in Illinois as we move into the winter months. We typically start to feel a more-steady chill that increases in November and continues into early spring.
Ideally, you’ve already had your furnace inspected and cleaned to ensure high performance when the system is called upon to serve you for the season. If you haven’t yet scheduled your maintenance, now is still better than never – just give us a call at Air Dynamics!
Because we’re heading into your heating system’s peak period, we thought it’d also be a good time to brush up on some important HVAC system awareness. The more alert and attentive you are to anything your furnace is trying to tell you, the more efficient and potentially less expensive your solution can be.
With that in mind, let’s review the different noises a furnace might make if it is beginning to struggle or fail.
What Do Different Furnace Noises Mean?
A properly functioning furnace in Oswego, Yorkville, Naperville, Aurora and Plainfield might still make some standard sounds when starting up. What you want to watch for are the noises that indicate something might be wrong with the system.
The following are several signs of a possible problem. If you become aware of any of them when your furnace is running, be sure to let us know as soon as possible. We can inform you about what the trouble might be as well as the best next steps to resolve it.
Furnace Noise: Clicking
One of the most common furnace noises, clicking often suggests an issue with the igniter trying to light the furnace burner.
Hearing one click when the furnace is heating up is fine. Multiple clicks may suggest the ignition-control board is failing, the burners are dirty or the gas valve isn’t opening properly. If the furnace is notably older (e.g. 20 or more years), clicking could indicate the pilot light is out or the thermocouple is bad.
Furnace Noise: Banging or Popping
Highly noticeable banging or popping noises in the heating system are not normal and should receive prompt attention. A frequent cause of banging sounds can be delayed ignition of the gas. If the gas burners do not ignite on time, gas can build up in the combustion chamber, so when the burners do eventually ignite, they create a small explosion. The issue could be a clog, a poor air-to-gas mix, dirty or contaminated burners, or a problem with the supply or pressure of gas.
In some cases, the noises can result from expanding or contracting ductwork while the furnace is operating. When warm air reaches the cold ducts, the ducts’ sheet metal will enlarge to suit the change in temperature, making it bang or pop.
Furnace Noise: Whistling
A whistling sound is often a sign of restricted airflow. The restriction could be caused by a dirty air filter or closed vents. If you hear whistling, first check the filter and the vents. Replacing the filter or opening the vents a little more might make the sound go away. If it remains, there could be an issue deeper in the ductwork.
Furnace Noise: Buzzing or Humming
The furnace capacitor might buzz or hum for a moment when it is providing an electrical boost to activate the blower motor. Beyond this, the system shouldn’t buzz. If it does, it’s typically symptomatic of an electrical problem such as bad or loose parts in the blower or inducer motor or an issue with the transformer or blower-motor capacitor.
Buzzing or humming should be attended to right away because the underlying causes could also loosen or damage other furnace components.
Furnace Noise: Knocking
Most knocking noises are abnormal, and they can have several possible causes.
A normal knocking sound will be emitted by the furnace cabinet or ductwork when the system is heating up for a cycle or cooling down after one.
Abnormal knocking can be produced by:
a loose or broken part, such as the blower motor, blower fan or inducer motor;
excess dirt on the blower, which can make its exertion unbalanced;
a clogged or dirty filter, which can knock against the support frame;
loosening ductwork, which should be inspected.
Furnace Noise: Gurgling
Condensation moving through the furnace drain, drain pump and heating system are signs the system is properly operating. If you start to hear steady, audible gurgling, there may be an irregularity with the condensation.
If the unit isn’t correctly getting rid of the condensation, it might also begin shutting down or leaking water around the pump and line. There could be a bad pump or a blocked condensation line.
Furnace Noise: Squealing
A high-pitched squealing noise often indicates a potential motor problem, such as bad bearings or a damaged belt. If you notice the issue early enough and contact Air Dynamics, the fix can be potentially swift and help to prevent a bigger and more costly repair.
Furnace Noise: Scraping
Scraping noises can be a tip-off of worn-out ball bearings, a loose blower wheel or a cracked heat exchanger. If you hear scraping sounds, turn off the system and call Air Dynamics.
Other sounds to pay attention to can include:
Noise | Possible Cause |
Whining | Bad or dirty blower or inducer motor; dirty burners |
Thumping | Unbalanced blower wheel; loose or broken parts |
Rumbling | Dirty or faulty gas burners; cracked heat exchanger |
HVAC Component Spotlight: Furnace Exhaust Fan & Motor
The furnace exhaust fan – also referred to as the inducer – is the high-powered fan that helps to expel combustion gases from the heating system. It ensures that toxic fumes do not remain inside of the furnace, especially in the combustion chamber.
When your furnace burns gas, it produces heat, water vapor and carbon dioxide. The combustion process also creates by-products including nitrogen oxide, sulfur oxide and, of particular relevance to safety, carbon monoxide.
The exhaust pipe’s job is to remove these harmful gases from your home and vent them outside. Attached to the inducer fan, it achieves this by forming a draft through the combustion chamber and heat exchanger. As the gas combusts, the flue gases flow through the heat exchanger, exit the exhaust pipe and empty outside of the home.
The furnace’s exhaust fan motor is clearly critical to your heating system and especially your safety. Concerning the fan motor, you can be a proactive, conscientious homeowner by being aware that:
a loose part will often knock or rattle against others; in older models with belt-driven motors, a worn or damaged belt can cause knocking or screeching as well
bearings that are going bad can produce a loud, constant noise
sloshing water can indicate the fan motor or the whole furnace might have been installed with an improper pitch; if the motor housing is at an incorrect angle, it won’t drain water correctly
debris or pest nesting in the motor can cause noises; if it builds up enough, the motor might not be able to turn at all
system clogs can make abnormal noises as signs the motor is working harder to push out through the blocked sections
HVAC Maintenance, Repair & Installation: Contact Us Today
A healthy furnace contributes greatly to a happily heated home. As your community HVAC contractor serving Oswego, Yorkville, Naperville, Aurora and Plainfield (IL), we can help you diagnose and correct any noises that might be saying there’s a problem. We’re always here for the furnace maintenance, repair and installation you need – just give us a call at (630) 731-1550!