There are a variety of problems that can cause your furnace to produce loud noises. Types of noises such as scraping, banging, whistling, and popping may be a sign of a loose part, cracked heat exchanger, or dirty gas burners.
If your furnace suddenly produces loud, sudden banging or booms, you should call an experienced technician as soon as possible. These sounds could indicate stuck ignition, a potentially dangerous situation involving carbon monoxide which is deadly.
Most frequently, the cause of a noisy radiator is air being trapped inside the system. If this is the case, it is recommended to fix this issue as soon as you can. If you find you can hear noisy pipes (especially during colder weather) this could be down to a frozen condensate pipe.
Loud Bangs, Rumbles, Knocks, or Booms
Loud noises like this are a sign of a build of gas in a furnace. The noise you hear can mean your heat exchanger is at risk of cracking. Even worse, it's a sign that something dangerous could happen if you continue to use your heater.
7. Grinding, Scraping, or Clanking. If your furnace sounds like a train grinding and scraping away on tracks, then you probably have an issue with the blower wheel.
Thumps and bumping noises, like an unbalanced washing machine, often indicate an unbalanced blower wheel or motor. This is a serious issue that requires immediate HVAC repair. The blower wheel and motor are major furnace parts and you don't want them bouncing around.
If your fan belt is wearing out, you may get a squealing noise while your HVAC system is running. Your motor may also need lubricant. HVAC motors require a very specific type of lubricant. If you are more comfortable with having an expert take care of it, an HVAC technician would be happy to help.
If your furnace is making an obnoxious noise, it's likely because the furnace blower motor is turning on and off as part of normal heating furnace cycles. Make sure your thermostat is set properly to the desired temperature and off when you don't need heat (like overnight).
Tighten the motor mounts and see if that solves your issue. If it doesn't, insulating the blower might be the best solution. If that doesn't work, then you may need to replace the whole blower. If the annoying sound is a screech, you might just need to oil the blower motor.
At times, it may sound like an off-balance washing machine; at others, you may hear noises resembling something more like that of a jet engine. If you notice your furnace making a rattling or rumbling noise, or other major changes to the way it typically sounds, you're not crazy.
The seven most common loud noises from your furnace include a rattling sound, a chirping noise, a banging sound, a squealing or whistling sound, a buzzing sound, a scraping sound, or a popping or clicking noise.
Step 1: Turn off your central heating and wait for around 20 minutes for the system to cool down. Step 2: Lay a dry cloth or towel beneath the radiator you want to bleed, just in case any water escapes. Step 3: Use your radiator key to slowly open the valve, turning it anti-clockwise to do so.
Furnace Screeching or Scraping
The blower fan may have come loose, letting the blades drag across the furnace casing. A scraping noise can also indicate other parts of the system have loosened. If you are unsure of the cause of the noise, turn the furnace off and have a technician come and take a look at it.
If your furnace produces a loud humming or buzzing sound, there could be an issue with the motor. There may also be something wrong with the fan. It can be something as simple as a loose screw, loose door, or improperly installed furnace filter.
Instead, you should take immediate action and contact an HVAC professional. A cracked heat exchanger can produce different sounds, including popping, banging, whistling, or scraping.
Over time, normal wear and tear can cause the furnace motor to start squealing, grinding, buzzing, or whistling sound.
Replacing a furnace blower motor costs $560, on average. Depending on the size and type of motor, most people pay $300 to $900. The average blower motor replacement cost is $560, but the final price depends on labor fees, as well as the cost of the parts.
Restrictive vents or grills: A vent that isn't the right size or shape can make a ton of unwanted noise. Some vents aren't made very well and have very narrow openings for air to enter or have vents that fall closed easily, which means that the HVAC system or furnace has to work super hard to get enough return air.
A constant low buzzing or humming noise could indicate an electrical problem. This could be anything from a faulty capacitor, a problem with the fan motor, or an issue with the transformer.
Several things can make your AC unit sound like it's preparing for takeoff: Fan Issues: Sometimes, the culprit is as simple as debris stuck in your AC's fan, or maybe the fan blades aren't aligned correctly. It doesn't take much for these elements to disrupt your peace.
If you hear similar clanging or loud banging noise in the walls, it can be a sign of clogs or air pressure in the system called a water hammer. If you don't resolve the problem, it can cause damage to the pipes, so consult a professional.
A loud buzzing noise almost always indicates that your furnace is working hard to generate warm air. This may mean that its blower fans are extremely dirty or that the motor powering the furnace fans is beginning to fail.
Over time and lots of use, air can creep into your central heating system and, when enough air gets trapped, it can cause your pipes and system to make noise. Water and air flowing through pipes and radiators can result in clicking, ticking or tapping noises.
Rattling (Inside the House), Clanking or Banging
Like “thwapping,” these sounds could be related to the furnace's blower assembly or motor, and are likely due to something being either loose or broken. If you hear louder banging sounds when the blower is running, shut the system off until you can get help.