It can be very scary and intimidating when your heater makes a loud bang when it turns on. For light sleepers and mothers with young babies, it can give you sleepless nights you never wish to remember. Here are a few major causes of heater noise and the tips on how to get rid of it:
Dirty furnace burners
If the noise occurs only when your furnace turns on and it lasts for several seconds or minutes before you start feeling the hot air, your furnace burner may be dirty. Accumulated dirt on the furnace burners will cause gas to collect on the furnace before it ignites. The delayed ignition from huge gas build-up brings about the big bang comparable to a mini explosive.
You should never ignore this noise since delayed ignition may eventually crack the heat exchanger of your furnace. When this is cracked, you will have to purchase a new furnace and can be quite expensive.
Seek the services of professional heater cleaners if this is what causes the noise.
Delayed gas ignition/explosive problem
If the banging noise comes from the heater, then the delayed ignition is the likely cause.
Delayed gas ignition as discussed above, occurs when the gas in your furnace builds up instead of igniting immediately. The delayed ignition may be caused by the following conditions:
- Excessive air mixing with the gas, making it difficult to ignite.
- Too little gas reaching the burners due to low gas pressure from the supply.
- Restricted, dirty, or weak pilot light for older furnace models.
- Misaligned or dirty furnace burners
Expanding and contracting air ducts
If you hear clapping noise a few meters away from your furnace, then the issue is most likely in the air ducts. When the furnace’s blower begins, it both sucks in air from around the home and blows it out through the supply ducts. This makes different portions of your ducts to contract (pop in) and expand (pop out). This may cause little noise since the minor popping is natural. If the expansion and contraction are severe, it may result in loud popping and banging noise and maybe as a result of the following conditions:
- Undersized ducts- As the blower pulls and pushes air through a very small area, it may cause strain on the air ducts.
- Closed vents- Will make the blower struggle harder to push out and pull in air, making the ducts to forcefully expand and contract as a result of the increased air pressure. The same amount of air tries to get in through squeezed passageway exerting more pressure on the open passageway.
- Clogged air filter- This may make it difficult for your blower to pull in the return air, hence causing the return ducts to forcefully pop in generating loud bangs.
Try opening the air vents and change the furnace filters and see if the problem goes away. If that doesn’t work, you may need to call professional heater technicians for further troubleshooting. They may advise you further on what needs to be changed especially if the ducts are undersized.