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Why Is My Furnace Making Loud Noises?

A man setting the thermostat on his home

Loud noises coming from your heating system can happen due to various reasons. The main issue is to determine the source, then figure out how to resolve the problem. While you may be able to make your own repairs, others will need the professional service of one of our technicians at Valley Heating, Cooling, Electrical and Solar.

The following are the most common types of furnace sounds and what they could mean:

  • Whistling - If you recently noticed a whistling noise, your filter could be clogged, causing the fan to suck air from other areas. Air being sucked through small spaces and tiny holes causes the whistle, so check your filter to see if the whistling stops. If so, then replace your filter with a new one. If the whistling continues, there may be gaps present in the duct such as a small hole near the duct or furnace blower, or the ducts are too small. If youandrsquo;re not sure, contact our technician.
  • Loud boom - If you hear a loud bang as soon as you turn on your heating unit, there are two potential issues: a delayed gas ignition or expanding and contracting metal ductwork. Delayed gas ignition occurs when gas builds up within the furnace, as opposed to igniting right away. When there is a delay in gas igniting, a miniature explosion happens and can damage your unit. You need professional help to fix the issue. If itandrsquo;s due to expanding and contracting ductwork, try changing the air filter and open all your homeandrsquo;s vents. If the noise persists, contact our technician.
  • Rattling - This type of sound happens when a panel and other components are loose, which only requires tightening or perhaps more screws. If the rattling noise continues, then it could be a serious problem, such as a faulty or cracked heat exchanger, that needs to be repaired by our technician.
  • Scraping - If you notice a metal-hitting-metal sound or metal scraping, there are three possible causes: a loose blower wheel, a broken blower wheel or a damaged motor mount. When blower wheels become loose, they contact the housing, resulting in a scraping sound. However, this can damage the blower wheel and housing. A broken blower wheel vibrates within the housing, causing a scratching or squealing sound. A broken motor mount dislodges a blower wheel, causing it to rattle against the housing. All these problems require professional repairs from Valley.
  • Squealing - This type of sound could mean your motor components require lubrication. But if the issue persists, it could also mean the motor requires repair or you need to replace your blower belt. All these tasks should be handled by our technician.

If you notice any one of these sounds from your heating system, contact our San Jose technician at Valley Heating, Cooling, Electrical and Solar today and schedule a free estimate.

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