Your furnace is designed to function quietly, with simply a soft hum or mellow whoosh of air. But when that turns into a banging, whistling or any other weird sound, it usually means something inside the unit isn’t working as intended.
The most normal issues are loose parts, clogged filters, grimy burners or electrical concerns. Over time, everyday wear and tear can also produce loose screws, clogged filters and fan motors to strain.
At times, airflow constraints in your ductwork or fractures in your heat exchanger amplify the noise even more. Put simply, furnaces are not expected to be loud. If yours is, it’s time to listen more closely and take a closer look.
That said, here below are several of the more everyday noises that you might hear and what could possibly be the cause.
Additionally, we’ll consider when it’s time to contact the professionals at AC&R Services, located at 217 Turkey Path Road in Sugarloaf, source PA.
Clogged filters can lead to whistling sounds
Air filters clean the air that is taken in by the furnace, heated and pumped into the house. When these filters are blocked, the furnace becomes inefficient, which means a decrease in airflow. This could cause the furnace to make a shrill buzzing or whistling noise.
First, you’ll want to replace your air filters routinely to make sure the system works at its highest efficiency. If replacing the filter doesn’t end the noise, it’s best to have the furnace checked by a certified HVAC professional from AC&R Services.
Banging or booming: The sound of a small explosion
A loud bang or boom can seem like a mini-explosion and, naturally, it’s always distressing. This noise is usually due to a delayed ignition.
When gas builds up in the combustion chamber prior to its igniting, it produces a tiny burst when the burners eventually do fire. This can take place if your burners are dirty, stopping them from igniting instantly. Over a period of time, this dirt can collect on the burners, leading to this potentially hazardous pause.
Beyond the alarming noise, this problem can place unnecessary strain on your furnace, including the heat exchanger, and can even create a potential risk of a fire.
If you do hear a loud bang or boom, particularly when the furnace turns on, we advise you to turn off the furnace at once. Do not try to relight it. This is a safety issue that needs the expert attention of the folks at AC&R Services.
Clicking, buzzing or humming: The electrical connection
At times, your furnace’s multipart electrical system can be the source of a bizarre noise.
- Regular startup clicking:A couple of clicks right after your thermostat kicks in is normally the sound of your ignition system engaging. This is an entirely ordinary sound.
- Repeated clicking:However, if you hear a repetitive clicking at the startup and the unit doesn’t ignite, it’s a signal of a hitch in your furnace. This frequently indicates the gas burners are not igniting, which might be a safety issue.
- Buzzing or humming:A constant buzzing or humming sound frequently signals an electrical issue, including a defective capacitor or a glitch with the transformer box.
Any strange electrical noise must be taken seriously. A defective electrical part can overheat and create a fire risk. If you are suspicious of an electrical issue, it’s best to turn off the furnace and contact the professionals at AC&R Services.
A chirping sound is evident
Another familiar warning sound a furnace can make is a chirping sound. If it sounds as though there’s a tiny bird trapped in your furnace, you’ll absolutely want to investigate.
In the best-case situation, chirping could signal that your furnace is warming up after switching on, particularly if the sound takes place at the onset of the cold season. This is completely normal.
On the other hand, it could mean that the blower motor’s pulley is misaligned or the mounting plate is contacting the blower wheel, particularly if it clangs like a metal chirp or squeak. Once more, if it doesn’t disappear after the furnace stars up, there’s a decent chance there’s something wrong with your HVAC system and you’ll want to call the experts at AC&R Services.
My furnace is rattling all the time
If you hear a continual rattling noise, it’s also a distinct sign there’s something amiss. That said, there are several explanations why a furnace is rattling, some of which are more serious than others.
For instance, a rattle might mean that there are loose bolts in the access hatch. If so, simply take a wrench and give the loose bolt a quick tightening. True, this might be an indication of normal wear and tear, but it could also mean your system is simply getting a bit old.
A rattle might also point to a crack in your heat exchanger, burner or blower motor fan belt. If this is the case, you’ll need to contact AC&R Services to identify the exact problem and perform any required repairs or replacements. At any rate, a rattle is a noise that cannot be overlooked.
I hear a hissing sound
Hissing sounds coming from your furnace just might be air or gas escaping within the system. This kind of noise may stem from a leaking gas valve or a heat exchanger crack, both of which demand immediate attention because of would-be safety concerns.
When to call the professionals at AC&R Servies
While certain furnace noises can be solved with normal maintenance, others need the know-how of a skilled HVAC professional from AC&R Services. Here are several symptoms that it’s time for licensed help.
- Continual or worsening noises.If the noise persists even with your troubleshooting efforts, it’s safer to have a technician evaluate the situation.
- Gas smells.A sulfur-like odor, often defined as a rotten-egg smell, could point to a gas leak, which is particularly risky. Shut off the gas immediately and call a professional.
- Repetitive ignition delays.Booming sounds after ignition delays need be tackled a.s.a.p. to avoid damage to the heat exchanger.
- Complex mechanical problems.Issues with the blower motor, fan or heat exchanger demand specific expertise and tools to repair safely.
A professional inspection for the technicians at AC&R Services not only solves current issues but also helps thwart potential breakdowns by pinpointing wear and tear or hidden glitches in your system.