Why Is Your Gas Furnace Making Loud, Unusual Noises?

Is your furnace suddenly making loud, unusual noises? When a gas furnace is operating, it should do so quietly. When you turn on the furnace, you may hear a rumbling noise in the ductwork that occurs as the air pushes through the ducts and expands them. If you are hearing popping, screeching, scraping, or rattling sounds coming from the furnace, something is not okay. Below are four potential causes of these sounds and what you can do to quiet your furnace.

Frayed Blower Belt

The furnace blower is the component that blows hot air from the furnace into the air ducts. It runs with the help of the blower belt and motor. The belt can wear out due to old age or poor maintenance. When this happens, you will notice a squealing sound when you turn on the furnace. Over time, the blower belt will stop working, causing the blower to fail as well. Replace the faulty blower belt to restore furnace operations.

Worn Blower Bearings

Besides the belt and motor, the blower has bearings as well. They help the fan to spin inside the motor housing. Bearings require lubrication to work quietly. If there is no lubrication, the bearings will grind against each other and produce a screeching sound. This slows down their performance, causing the fan to seize up and make a loud noise as well. Lubricate the motor and bearings regularly to prevent these sounds. If the bearings are worn, replace them as well.

Dirty or Worn Burners

The furnace burners are the components in which air and natural gas mix and burn to create heat. The resulting heat is blown into the ducts by the blower. Dirt from the air and rust from the metal components can build up on the burners, clogging them and causing ignition delay. Therefore, gas builds up and explodes when the ignition turns on. You will hear a popping or banging sound when you turn on the furnace. You should clean the burners to prevent an ignition delay. If the burners have cracks or rust, replace them to avoid loud noises.

Unbalanced Air-to-Fuel Ratio

An imbalance in the air-to-fuel ratio can be problematic for your gas furnace. For the gas to ignite, the air and fuel must be in adequate quantities. If the oxygen is inadequate, there will be incomplete combustion. This will cause soot buildup on the burners, leading to blockage and delayed ignition. Consequently, the furnace will make unusual noises when you turn it on. A heating contractor can correct a bad air-to-fuel ratio in your furnace.

Furnaces have many mechanical parts, and it may be hard to pinpoint the exact cause of the noise. Contact a heating system repair team for troubleshooting and more.