Over a period of regular use, you may begin to notice that your furnace makes some noise when it is on. Although many sounds are completely normal and do not indicate a problem, other sounds are signs that your furnace is in some sort of disrepair and needs immediate attention. Here are some sounds you may hear and what they can mean for your home's furnace.
A screeching sound is often a result of worn down parts inside the furnace system. You can hear this sound when a bearing has slipped from its normal position. You should have your HVAC contractor check the furnace right away to prevent further damage. The problem may be remedied by a simple recalibration and tightening of components. If caught early, this will not be a major problem for your system.
Some banging sounds are not necessarily an issue as long as they are infrequent and quiet. The air ducts contract and expand over time. The ducts are made of metal, and it is normal for the material to change shape as they get older and based on the temperature at the time. If you hear continuous loud banging sounds, however, you need to have the furnace checked professionally. This continuous loud noise can indicate a major problem with the different components of the furnace.
A scraping sound is never welcome in any part of an appliance, particularly one as important as a furnace system. The source of the noise will determine how big of an issue you have. Some scraping may happen occasionally because there are bolts or other loose parts that just need a quick adjustment. However, you may have a problem with the blower wheel or another major component. If the sounds do not stop after you check the system for anything that may be obviously loose, you should call your HVAC contractor to check on the furnace.
A grinding sound coming from your furnace is highly unusual and is cause for concern. Grinding metal noise is often caused by the worn-down bearings within the system. Over time, the bearings get weaker and can cause friction. The grinding sound is a result of that friction. This is a major issue that requires immediate attention from a professional. If you do not have this problem repaired, the furnace will continue to wear down and can cause permanent damage.
If you notice any of these issues, contact a furnace repair service.