Why Is My Heating Oil System Making Noises?

Find Out What Noises Are Normal—and What Are Not

Many of the sounds you typically hear from your heating oil system are perfectly normal, especially when it starts and stops running.

Let’s start with heating oil furnaces first. A furnace refers to the heating unit in a warm-air, or forced-air, system. After air is heated in the furnace, a blower forces it through ducts. The warm air is then released through vents or registers in your Wisconsin home.

To help you distinguish between minor and major problems with your warm-air furnace, here is a list of common sounds you may hear. Please be aware that these are general guidelines provided solely for educational purposes. A correct diagnosis can only be made after a system inspection by a heating oil service professional.

Humming: This usually comes from the transformer; all transformers hum to some degree. If the humming begins to increase, it’s an early signal that the fan motor may be wearing out. Immediate attention is not needed but an inspection should be done soon.
Scraping: This often happens when the bearings in the blower motor wear out. If you hear this noise, shut off the furnace at once to avoid further damage. Then call your heating oil service company.
Squealing: If it’s an older furnace, the blower motor may need oil. There may also be a loose belt.
Vibration: The blower wheel or motor may need to be rebalanced.
Whistling: This noise could mean that a dirty filter is constricting airflow. All warm-air systems have an air filter to screen out dust and other impurities. In general, you should check the filter’s condition about once a month during the heating season and change or clean it when necessary. Refer to your owner’s manual for instructions or contact your heating oil service provider if you’re not familiar with this procedure.
Popping: Abnormal air pressure makes ducts pop in and out. This can be caused by a clogged filter, an undersized or flimsy duct, or closed vents.
Creaking: When air gets forced through your ductwork, you may hear a creaking noise because the ducts are expanding and contracting. This usually doesn’t happen with a properly installed variable speed system. There will be reduced air turbulence because the system doesn’t “blast” on and off.

Banging Noises from Boilers

In Wisconsin, some people may have a hot water (hydronic) system. To deliver heat to your home, water circulates around your boiler’s combustion chamber. A circulator pumps the hot water through pipes to heat baseboards or radiators. Eventually, the water returns to the unit to begin the cycle again.

Steam boiler systems work similarly except they generate steam, which rises to radiators (no circulators are needed). A low water cut-off shuts down the boiler if water levels drop too low, preventing boiler damage.

A noisy boiler can be a fairly common problem for people who have a closed-loop hot water boiler. Like a radiator in your car, your boiler is filled with water. But if air leaks into the system, the pressure rushes through the pipes. This results in a banging noise.

This happens because air can be drawn into the system in several different ways. This includes a defective valve, a broken bleed screw, a pressure leak, or earlier repairs done to piping.

Another possibility is a problem with the expansion tank. Because water expands when heated and contracts when cooled, extra space is needed to store air. This is called an expansion tank. But air can be drawn back into the boiler from this device.

Get Professional Service If You Have Concerns

If you have any concerns about whether your boiler or furnace is working properly, please reach out to your trusted Wisconsin heating oil service provider to request an inspection and evaluation of your heating oil system.

If you’re ready to explore new heating oil system options for your home, your heating oil equipment service provider will be happy to help. Please remember to ask about any rebate opportunities available in Wisconsin for new heating oil equipment.