When your furnace makes a strange noise, you start wondering about a few things. Does it always happen, and is this just the first time I’m hearing it? Is a big repair bill in my future? When is the last time it was serviced? While you’re busy thinking about these things, you’re also waiting for the furnace to kick on again to see if the noise is still there.
At Jack Hall Plumbing & Heating, our experienced HVAC technicians know what your furnace is trying to tell you with those clicks, rattles, buzzes, and bangs. Here are some of the most common furnace noises our customers call us about and what they might mean regarding how your unit is running.
Clicking: One click is OK to start the cycle and light the furnace, but multiple clicks without ignition means there’s a problem. The cause could be from various things, including a bad ignition control board or thermocouple, dirty burners, a faulty gas valve, or even a cracked heat exchanger. If the clicking sound doesn’t quit after the furnace has been running for a moment, call us at Jack Hall right away. Ignition issues are one of the leading causes of residential carbon monoxide poisoning.
Thumping: If your furnace sounds like you’ve got sneakers in the washing machine, it probably means a piece of the unit has broken loose and is thumping against the frame. It could also mean the blower wheel or motor is unbalanced, creating the potential for serious problems. Have your furnace checked by an HVAC pro to find the source of the noise and rectify it.
Buzzing: A quick buzzing sound is usually the capacitor boosting the blower motor. The furnace’s capacitor stores electricity to help its motor start up when the thermostat triggers a heating cycle. If the capacitor goes bad, you will hear a buzzing sound. The same applies to a failing blower motor which will generate a buzz. Any buzzing should be addressed quickly because it’s likely to be an electrical issue.
Booming: If you hear a “booming” sound when your furnace starts up, it’s probably due to delayed ignition. It happens when the gas builds up as the burners struggle to ignite, and when they finally kick in, it generates a mini-explosion and “BOOM.” This sound requires a service call because over time these booms damage other key components of the heating system.
Rattling: If you hear a rattling noise coming from your furnace, there are several reasons why it might be jumping around. It could mean loose bolts in the access hatch, a crack in the heat exchanger, or the blower motor fan belt. You’ll want to have a technician diagnose the problem and perform necessary repairs.
Grinding: The most likely cause is that the blower fan is loose or broken. A loose fan can grind against the housing when in operation. A broken bolt or other hardware can sometimes get lodged in the blower fan or motor, causing that horrible metal-on-metal grind.
Squealing & Ringing: A high-pitched noise coming from your furnace often means there’s an issue with a motor bearing in the blower. Over time, dirt buildup or faulty capacitors can wear out the bearing. Also, a bad blower wheel can cause loud ringing that you definitely won’t be able to ignore. Schedule a service call because issues related to the blower can cause it to overheat which is a fire hazard.
Whistling: Our technicians tell customers to make sure to regularly change their HVAC filters all the time and this is another reason why. If you’re hearing a whistling sound from your furnace, it’s probably a dirty filter. When the filter is clogged, air whistles through the narrow openings. If you hear a whistle, open your vents and change the filter. If the noise is still there, call a technician to investigate further.
Chirping: Another common warning sound a furnace will make is a chirping noise. It might mean that the pulley for the blower motor is out of alignment or that the mounting plate is touching the blower wheel, especially if it sounds like a metal chirp
Rumbling: A loud rumble that you can feel throughout the house could be caused by fuel continuing to burn in the furnace even after the burner turns off. Have a professional check your rumbling furnace because it could be releasing carbon monoxide into your home.
If your furnace is making weird noises, our experienced HVAC technicians are ready to diagnose the problem and come up with a repair solution that will get the unit back up and running quickly. Even if your furnace sounds great, don’t forget to schedule regular service calls with Jack Hall Plumbing & Heating to keep things running smoothly and safely so you can feel comfortable and safe in your home.