What is Furnace Flame Roll Out

Gas furnaces are among the safest appliances any home can have. However, it is recommended that all furnaces have routine maintenance and repairs done. Parts that do not move still degrade from corrosion and soot damage which can lead to burners and exchangers to develop a very dangerous flame roll out condition.

A gas furnace works by mixing air and natural gas traveling through a burner that heats up a metal heat exchanger. The combustion chamber is separate from the heat exchanger that gets forced air blown over it, and is heated by the heat exchanger and then exits through the heat ducts.

The burners of the gas furnace are located at the bottom of the heat exchanger. All the parts of the gas furnace from the burners to the heat exchanger are made of metal. Over the years, corrosion and soot products start to interfere in the travel of hot gases from the flames up and out of the flue. Flames that were once confined to the immediate area of the burner spread out as a flame roll out when the air and gas exchange is impeded.

Damaged Heat Exchanger

Forced air units create air pressure outside of the heat exchanger that is greater than the pressure on the inside of the unit where the combustion process occurs. Even the smallest of holes and cracks can cause an eddy, which is a rotational movement of gases disrupting the flow of byproducts and has the same effect as restrictions in a heat exchanger passage, causing a flame rollout. Heat exchangers with cracks or hoes that have rusted through also cause flame roll out which increases the danger of carbon monoxide gas to enter into the home. CO is deadly in small concentrations, and it is also odorless and tasteless so it cannot be detected by a person’s natural senses when present.

Signs of Flame Roll Out

Flame roll out is a serious and potentially deadly safety concern. There may not be any exterior indication of a problem in the early changes but can usually be seen on some furnaces as  a discoloration of the exterior painted surfaces around the combustion chamber.

Why Furnace Flame Roll Out is Dangerous

Any gas combustion that is not properly confined to the appropriate area could obviously have consequences.  This condition is serious and requires immediate attention because it can cause damage to the insulation on electrical wiring, gas valves, and combustible materials nearby. Many surfaces have a flame roll out switch that cuts off gas to the burners when flame roll out is detected through temperature sensors. However, there have been many instances of the safety switch being circumvented by homeowners and even repair personnel.

Regular furnace maintenance is recommended to help prevent furnace flame rollout. A professional heating technician will check for malfunctions, giving you the peace of mind knowing your furnace is operating safely and efficiently all winter long.

Call Ace Hi Plumbing, Heating & Air today with any questions or concerns you may have about furnace flame roll out.