Furnace Cleaning and Blowback




Did you know that furnace flues need annual maintenance, no matter what type of fuel is used? Most customers often have the idea that the furnace cleaning, and flue, are handled by the fuel supplier. It is not. It’s probably the number one surprise to our customers when we tell them that. You should never neglect your furnace flue. One reason is that debris can block the flue and cause soot to blow back into the house. This can lead to carbon monoxide fumes entering your home. Carbon monoxide poisoning can result in illness and sometimes even death. An annual furnace flue inspection by professionals can help to ensure that it’s safe to use your furnace.


Potential problems in the flue caused by a furnace are different from those caused by a wood-burning fireplace or stove. Oil and gas furnaces produce by-products and acids which can literally eat away the flue lining. This is when carbon monoxide poisoning can become a real and serious danger. Carbon monoxide is odorless and invisible, so it often goes undetected in homes until it causes severe illness. You should have carbon monoxide detectors in your home as well as smoke detectors. They are separate devices. You need both! They’re essential and check them routinely to be sure they are still working.


Not only do acids cause damage to furnace flues, chimney masonry can also suffer deterioration from acids and water damage.

Any type of blockage is bad. It introduces the same dangers causing carbon monoxide to find paths into the home. In a furnace flue inspection, birds’ nests and all types of debris are removed from the flue so that the heating system can operate safely.

When, or if there is a conversion to a gas appliance, building codes require that the flue be inspected and cleaned before the change is made. The accumulation of oil or coal soot will eventually lose its bond to the interior walls and drip down the flue. When aided by moisture problems in the stack, the gases produced by the new furnace can cause the clean-out and flue opening to both become clogged.

The size of the furnace flue must also meet the requirements of the appliance; otherwise, a variety of problems can occur, such as too much moisture in the combustion gases in the flue. The sizing and configuration of the entire venting system is a crucial elements to the safe use of your furnace. This is another important reason you should depend upon professional chimney technicians for installation and maintenance.


Besides having an annual flue inspection to ensure that there is no blockage or damage in the furnace flue, the following are good times to have your furnace and flue checked:

  • Prior to moving into a new home
  • Before installing a new furnace in your home

While a furnace does not produce as much particulate build-up as a wood-burning fireplace, cleaning is important partly because the connections of your venting unit need to be removed and cleaned out. In addition, the build-up can cause your oil burner to run 30% less efficiently. Getting it routinely inspected will keep your burner operating smoothly saving you money!

1800 Chimney’s technicians and sweeps are fully certified and trained to clean all types of furnaces and heating appliances. The continued safe operation of your heating system can be assured with a regularly scheduled furnace flue cleaning and inspection. We also do fireplace and masonry repairs as well as liners, caps, and much more. Check out our services and feel free to give us a call.