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Diagnosing Furnace Issues

Diagnosing Furnace Issues

Not all furnace noises are created equal, but you shouldn’t tune them out assuming you just a have a loud HVAC system. Some sounds are an early indicator of a bigger problem. Don’t take for granted the age of your furnace. Even new equipment can develop problems that need to be serviced. Learn the different sounds you need to listen for, and take the time to get your heating system maintained at least once a year. Fix strange furnace noises as soon as possible.

Diagnosing Furnace Issues

Clicking Sounds

The clicking of your system turning off and on is normal. If you hear repeated clicking sounds unrelated to the systems switching itself on and off, you may have a problem. Listen to see if the clicking is coming from the control panel or outside the compressor. This sound may be an indication that a relay has gone bad. It could also be a problem with an electrical control.

Loud Rattling, Bumping, and Clanking

All of this noise may indicate you have a problem with blower assembly or motor. A rattling can mean a component is coming loose. Bring in a professional is your furnace is making a lot of racket. You need to have the blower serviced before any parts break or disconnect completely. If the sounds become louder when the blower is running, you need to turn your system off immediately. Sometimes motor mounts come loose or the blower is out of alignment. In any case, it is always better to be safe than sorry. If in doubt, shut the system off and get a repair person over to look at your furnace as soon as possible. In either case, the motor needs to be inspected by a qualified technician.

Squealing

Usually squealing or squeaking is an indication of a bad belt or possibly motor bearing problems. If you hear high pitched noises coming from the blower motor, it is most likely the belt. It should be replaced before it breaks. If the belt breaks, the blower will cease to turn. Sometimes these squeaking sounds are due to a lack of lubrication. All motors need a little oil every now and then. Add lubricant occasionally to help quiet the motor.

Thwapping

If something gets stuck in the blower blades, you might notice an odd thwapping sound. Another possibility is that something inside the housing is coming in contact with the blades. If this is the case, the sound may mimic that of a playing card attached to the spokes of a bicycle. This noise is not necessarily critical but it could cause your blower motor wear out faster.

Rattling Outside the Compressor

You don’t want your fan to rattle when the compressor unit turns on. Such sounds may indicate a failing motor or loose hardware. If the sound starts getting louder, the problem is getting more serious. You should seek out an experienced HVAC technician to remedy the problem. A noise that mimics a scream may be your compressor failing. Something more along the lines of a humming is more likely a bad motor or a failing capacitor.

When the winter months set in, your heater becomes quite important. It doesn’t take long for the temperature to drop in your home especially if you have an active household. Get your furnace serviced in the fall so you are less likely to have to deal with a faulty HVAC system. If you do start hearing new or weird noises, it is wise to contact a professional. They can ease your fears and fix any problems you may be facing before they become expensive. It is never a bad idea to have a store of blankets and a space heater ready for emergencies.

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Afton Jackson

Wednesday 13th of January 2021

You did a great job of explaining what a rattling sound might mean when operating a furnace. Come to think of it, it was only after I accidentally bumped into my furnace while holding a stiff piece of furniture that this rattling sound has been coming up when we turn it on. It's possible that there really is a part loose with it, so I'll look for a heating repair service in the area that can figure out what might have gone wrong.

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