How To Check the Flue in Your Furnace During the Heating Season

In the bitterly cold winters of New Jersey, your furnace is essential, burning gas or oil to keep your home warm. Dangerous gases are created during the combustion process. Sulfur dioxide, nitrogen dioxide, and carbon monoxide are all examples of this. To keep your home safe, these gases must be evacuated outside.

The flue, a huge metal pipe that runs from the furnace to a chimney liner or an independent flue pipe, is responsible for this.

How to Check the Flue in Your Furnace

The flue safely transports combustion gases through your home and up through the roof, where they are expelled over the roofline. Any obstructions, leaks, or damage to the flue could allow combustion gases to enter your home, posing a risk to your health.


Flue Problems in New Jersey Households: What Causes Them?

When the following conditions exist in the flue, combustion gases can enter your home:


  • The pipe has a leak.
  • A blockage in the flue caused by a foreign object
  • Backdrafting

When the furnace is unable to pull enough air from the interior of your home to feed the combustion process, it must instead draw air through the chimney itself, carrying the combustion gases with it.


Flue issues can be caused by a variety of factors, including:


Corrosion: Combustion gases contain a lot of moisture and acidic chemicals, which can corrode steel flue pipes and cause leaks over time.

Loose couplings: As the flue expands and contracts with temperature changes over time, loose joints can form, causing leaks.

Damage to the flue pipe can restrict airflow and cause backdrafting if it is damaged due to an accident or improper installation.

Inadequate airflow: If your furnace doesn’t have enough air to burn, it will backdraft. A powerful exhaust fan that creates negative pressure can produce this. It could also be caused by too many fuel-burning machines in a compact mechanical room or a poorly balanced HVAC system, which creates negative pressure and draws combustion gases within.

Broken tiles, bricks, and other debris can fall into the flue and stop it if it connects to a chimney liner or travels through an existing chimney.

If the cap is missing where the flue pipe exits the roof, debris can fall into the flue, or animals such as birds can establish nests in the pipe during the summer.

Where Can You Look For Your Furnace Flue?

The flue for the furnace is normally found on the top or back of the furnace. It will connect directly to a chimney or a vertically extending metal flue pipe on the roof. Although it may be visible in the attic, the majority of the remaining pipe will be hidden as it runs through your home.


How to Inspect Your Furnace Flue in Your New Jersey Home

The visual inspection of your flue pipe is the most important part of the process. Check the flue pipe for indicators of damage before each heating season, such as:




Joints that are loose

White streaks or water stains

Deposits of soot on the pipe or furnace

A missing flue cap or chimney damage may also be seen from the ground.


It is, nevertheless, advisable to consult a professional for HVAC repair service for a comprehensive flue inspection. Celestial Air can ensure that your flue is in good working order, clear of blockages, and correctly drafting.