Furnaces shouldn’t be musical by any means, so it should be an immediate concern if they begin hollering and screaming. While your furnace can hit all sorts of noises, these 5 are definitely ones that will make you want to call an HVAC professional.
Clicking: A clicking noise means that the spark igniter of your furnace is attempting to ignite the burners or pilot light, but it is just not working. The ignition system must be energized in order for your system to work. Only then can the gas valve open, the furnace burners light up, and the furnace blower come on and start blowing hot air into your home. There could also be issues with the thermocouple, which opens a gas valve to the furnace when it detects a pilot flame. It could also be that the gas valve is not energized. If there is no gas, there will be no ignition. If the gas valve remains shut, there will be nothing to ignite.
Booming: Do not ignore booming noises from your furnace. Most likely, delayed ignition is the source of the problem. This can actually end up causing severe damage to your furnace and burning you as well if you do not take care of it right away. What basically happens is that when your thermostat requests heat from the furnace, which will then cause a gas valve to open and send gas to the burners of the furnace. This will cause gas to build up within your furnace to continue to build up until it finally causes flames and explosion in your furnace. That is where the booming sound comes from.
Screeching: A screeching noise will likely indicate that there is an issue with the belt or motor bearing. Though it is not as dangerous as other furnace noises, it may cost you more money, the longer you wait to get it fixed.
Rattling: Rattling noises are a sign that parts are coming loose. The rattling itself is often due to components banging against each other. It is also possible that a rattling noise can mean that there is a potential leak in your heat exchanger. This can be much more dangerous, as it can result in carbon monoxide entering your home.
Chirping: Chirping sounds usually indicate the unit is warming back up from a long period of sleep. Usually, in these cases, the noise goes away when the furnace has been on and functional for a few minutes. But if you observe that the chirping sounds are still occurring even after many minutes, please call your HVAC professional for furnace service to have the problem inspected.