Gas Furnace Venting Into Chimney

I ran across a permitted 2003 installation today of an 80 furance water heater venting into a clay lined masonry chimney.

Gas furnace venting into chimney.

The rules apply to listed appliances. When the furnace exhausts into the chimney the gases quickly cool off before exiting to the outdoors. When did it become dis allowed to vent a furance and or water heater directly into a chimney or is it ever totally dis allowed. However using an interior chimney is extremely limited.

Chimneys are usually vertical or as near as possible to vertical to ensure that the gases flow smoothly drawing air into the combustion in what is known as the stack or. Gas and oil appliance venting. They can t all rise to the top of the chimney so some of them backdraft through the vent pipe itself and enter the home s crawlspace. This chimney rule can be applied to wood burning fireplaces heating stoves and any oil fueled appliances but remember that manufacturer requirements have to be incorporated into it.

The manufacturer s listing and instructions will preclude attaching any other appliances to it. The height of the chimney the area of the liner and the input of the appliance all play a role in the use of the chimney. To ensure proper venting however a liner must first be installed in the chimney. A chimney is an architectural ventilation structure made of masonry clay or metal that isolates hot toxic exhaust gases or smoke produced by a boiler stove furnace incinerator or fireplace from human living areas.

The different types of venting. Furnaces that vent into chimneys can be hazardous but they don t have to be. For instance a 100 000 btu furnace venting into an interior chimney with a 38 square inch liner would not be allowed regardless of chimney height. Well making sure that you choose the right venting style will protect them.

The exhaust system typically uses metal venting often routed into a chimney stack to exhaust the combustion gases created in the furnace fire chamber. I ve never seen one that recent not being lined up to the top so it got me thinking. For gas venting appliances the chimney flue venting rules are more complex simply because of the variety of products on the market. Gas fireplaces are factory built systems.

Appliances fueled by natural gas or propane may not produce the visible soot that appliances burning other fuels do but they can deposit corrosive substances in your chimney. But many don t realize that a gas heating appliance whether it is a furnace boiler or even a water heater relies on the chimney for proper venting of the exhaust. A conventional natural gas furnace will vent the dangerous combustion gases through a simple vertical exhaust system that is attached to the furnace. When we are talking about gas furnace vent pipe code we need to talk about the different types of the vents first after all you want to keep your family safe from harm.