The blower in newer furnaces is much stronger than older models, leading to the contracting and expanding of the ductwork attached to it. As the motor kicks on, you'll hear this popping as the metal ductwork expands to accommodate the strength of the blower.
Clean the Furnace: A buildup of dirt and debris inside the furnace can also contribute to popping noises. Cleaning the furnace, including the burners, can help resolve the issue. Replace Worn Components: If the popping persists, there may be a more serious issue, such as worn or damaged components.
Homeowners often notice a popping sound when the furnace begins a cycle. This is due to warm air that hits the cold metal of the ducts, which causes expansion and produces that noise.
Loud Bangs, Rumbles, Knocks, or Booms
Loud noises like this are a sign of a build of gas in a furnace. The noise you hear can mean your heat exchanger is at risk of cracking. Even worse, it's a sign that something dangerous could happen if you continue to use your heater.
Popping or Banging
There could be a few reasons why heaters make this sound, like dirty burners that need cleaning, or an excessive amount of gas inside the chambers. If you hear a banging or popping sound when the heater shuts off, it could mean your ductwork is contracting as the metal cools down.
When ducts are too small, it can create a buildup of pressure in the system, which results in a clicking or popping sound. These noises can occur when the heating or cooling unit turns on or off, and sometimes persist throughout the cycle of the HVAC system.
Insulate Your Ducts
Insulating your ductwork will help dampen sounds echoing throughout your home. The insulation will also help retain heat, reducing the fluctuation between hot and cold ductwork. A more constant temperature will lead to fewer pops due to oil canning.
There are a variety of problems that can cause your furnace to produce loud noises. Types of noises such as scraping, banging, whistling, and popping may be a sign of a loose part, cracked heat exchanger, or dirty gas burners.
Popping. If you hear popping sounds and you don't have a bag of popcorn in the microwave, you could be dealing with dirty furnace burners or damaged air ducts. When the burners are dirty, the buildup prevents them from igniting, which causes too much gas to build up, making a popping sound.
Delayed ignition is when that gas isn't ignited immediately, allowing the gas to build up in the furnace. The gas keeps building until—BOOM—it reaches a flame and finally ignites, causing a small explosion in your furnace.
In an electric furnace, if the thermostat wire touches the metal frame of the furnace, it can cause a blown fuse. When the wire touches the metal frame, it can deliver a higher voltage than the wires are meant to handle. This will cause a fuse to blow.
Defective Electric Igniter
Whenever you start a furnace with an electric igniter, electricity is used to ignite the flowing gas, but the igniter can be worn out over time. A worn-out igniter can periodically fail, and if it keeps trying to light the gas, your furnace will make a clicking sound.
If your furnace suddenly produces loud, sudden banging or booms, you should call an experienced technician as soon as possible. These sounds could indicate stuck ignition, a potentially dangerous situation involving carbon monoxide which is deadly.
The underlying cause of a clicking thermostat is purely mechanical. A thermostat has a circuit inside it that is connected whenever your thermostat realizes it needs to change the temperature. As the two small relays inside connect and disconnect, you can hear a tiny “thunk” from them moving.
Heating and AC equipment operates in a specific pressure range within air ducts. Ductwork responds to pressure changes at times by making popping noises. This is normal, so you shouldn't be alarmed if you hear it at times.
Over time, debris like dirt, grease, and food particles can accumulate in the burner ports of a gas stove. These clogs can disrupt the flow of gas to the burner, leading to irregular burning patterns and popping noises.
One of the most common furnace problems is a malfunctioning thermostat. A sure sign your thermostat isn't working properly is if your fan is constantly running. This will cause your thermostat battery to run, and cause your furnace to work inefficiently.
We're here for the long run. So if you hear a squeal, a new click, grinding, or popping when your furnace is at any point in the heating cycle, it's best to have a tech take a look and catch things early.
As the motor kicks on, you'll hear this popping as the metal ductwork expands to accommodate the strength of the blower. This sound isn't anything homeowners should be especially concerned with, as it doesn't indicate any problems with their home heating system.
If the furnace is running normally but there's a clicking sound coming from the ductwork or air vents, there might be a cracked or loose duct. You can have a technician check for this the next time you call them for duct cleaning. Damaged ductwork should be replaced immediately.
MY FURNACE IS MAKING A POPPING NOISE
This is usually the sheet metal in your ductwork responding to pressure — popping one way in reaction to the negative air pressure of the fan, then popping back when the fan shuts off and the pressure releases.