Why is my furnace making loud noises?

Bangs, Clicks, and Screeches: Why Skipping AC Maintenance Leads to Winter Nightmares

Often, a household is a busy place with lots of noise and activity. Our minds do not process all the stimuli that our eyes, ears, noses, and mouths take in during a single day. Even when everything settles and quiets down, there is plenty to hear. These are the background noises of life, different in each home, yet unique enough to make us familiar with our surroundings. 

A portion of that ambient sound is the familiar sounds of heating cycles during the winter. Some furnaces are whisper-quiet, and you barely notice the sound. Others are louder or more evident. Sometimes, a furnace will begin making noises that register as unusual and not a part of what is normally heard. Should you be concerned about loud, unusual noises from the furnace? Here is a short list of uncommon furnace noises and their significance and why you need AC maintenance.

The Link Between Noisy Heaters and AC Maintenance

Loud Pops or Bangs

The normal heating cycle involves a rather precise series of events with a singular result.

  • The thermostat registers that the indoor temperature has fallen below the comfort setting of the family.
  • It sends an electronic message to the furnace, calling for heat
  • The signal opens the gas valve, releasing gas from the burner assembly, AND
  • The signal also triggers the electronic ignition system to ignite the gas coming from the burner assembly.
  • Another sensor detects gas and shuts the valve if the gas does not ignite, preventing an explosion.
  • However, if the ignition system delays for an extra second before igniting the gas, the ignition causes a little mini explosion.

That doesn’t sound so bad; however, the delayed ignition releases enough energy that it can damage the ignition system, the burner assembly, and/or the heat exchanger. Any of these damages can cause the furnace to quit functioning. Damage to the heat exchanger can release carbon monoxide and carbon dioxide into the home.

Solution: turn the furnace off and call All Cool AC and Heating for immediate repair. This is a very serious problem.

Persistent Clicking

Gas furnaces are complex electromechanical devices, and various components will emit occasional clicks. The thermostat relay may click audibly at the start and finish of a heating cycle. Various relays and switches click inside and around the air handler cabinet. The electronic ignition will click a few times, creating a spark to ignite the gas. (If you have a gas range, you might be familiar with this clicking in the kitchen.) If this clicking persists after the gas is ignited and/or after the heating cycle has ended, this is a serious issue.

  • This malfunction of a component will cause it to wear quickly and fail.
  • Without an electronic ignition, the furnace will malfunction, resulting in chilly temperatures indoors as well as outdoors.

Solution: turn the furnace off and call All Cool AC and Heating for immediate repair or time to schedule an AC maintenance appointment.

Screeching or Grinding Noises

There are very few moving parts in a furnace. If you hear a loud, annoying grinding or screeching noise, it is most likely a problem with the blower motor assembly.

  • The blower motor powers a rather large fan cage, which draws air from the house, through the furnace, and back into the house.
  • The motor has bearings. The fan cage is turned by a belt or chain. Friction and wear can cause any or all these parts to fail, resulting in these loud, annoying noises.
  • This may result in the loss of heat, although that is not a universal result. It may get noisy and continue to move air throughout the home.

Solution: turn the furnace off and call All Cool AC and Heating for an AC maintenance appointment.

Secure Your Home with Routine AC Maintenance

Don’t wait for a noisy breakdown to realize your HVAC system needs professional attention. By scheduling regular AC maintenance, you can catch small mechanical issues and ignition delays before they turn into dangerous winter emergencies. Our expert team at All Cool AC & Heating is ready to inspect your blower motor, sensors, and relays to ensure your home stays quiet and safe all year long. Contact us today to book your preventative AC maintenance tune-up and enjoy the peace of mind that comes with a perfectly functioning system.