October 31, 2019

If you are noticing a loud noise coming from your furnace when it turns off it could be something very simple. The noise may be described as a loud boom or bang and can be disconcerting when you hear it, especially for the first time.

Below are some of the reasons you may be hearing a banging sound and how you may be able to fix those loud banging noises coming from your furnace.

Replacing a Dirty Filter
A very simple reason that you may be hearing a banging sound when your furnace turns off is due to the inside filter. If the filter is dirty or not placed correctly then air may not be getting out properly which will cause a backup. Once the furnace cycles off you will hear the loud banging noise as the metal in your furnace expands due to the excess air. Clean or replace your air filter regularly to stop excess dirt building up. If this does not help you may want to look into some other causes.

Cleaning Your Ductwork
The buildup in your ductwork may also cause banging noises to occur. This buildup is much like the air filter buildup in that it causes air to not flow correctly and become trapped. Having a professional clean your ductwork thoroughly can reduce or eliminate the loud noises you are hearing.

Adjusting the Dampers
The loud noises you are hearing could be due to the natural expansion and contraction that happens as your system is cycling on and off this is due to temperatures changing inside the ductwork. If this is the case then adjusting the dampers on the side that supply’s airflow to your home to an open position can help with the noises. You may want to open dampers one a time then test to see what kind of difference it makes to the banging sounds.

Adjusting the Actuator
Adjusting the actuator in your system can sometimes eliminate noises coming from your furnace. An actuator works to help push the air through your system. Adjust the actuator up or down until you hear a change in the banging sounds. If you are not confident adjusting your actuator you may want to contact a certified heat and cooling technician.

Cleaning your Fan
Another cause of noises coming from your furnace could be the fan that is used for both AC and heating and is found inside the duct work. If this fan is dirty it could easily be causing banging noises as it switches off, cleaning this fan may remedy the loud noises.

Furnace Repair Services in Baltimore, MD

Trust the professional heating and cooling specialists at Air, Plumbing & Heating Solutions to maintain and repair your heating system. After all, we’ve been serving and servicing folks in the Baltimore area for over thirty years. Call on us to inspect your system and trust your hometown’s HVAC team for all of your heating needs.
Call us at (410) 702-4219 or fill out the contact form on the right to schedule an appointment!

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