Venting Hot Water Heater And Furnace Through Chimney

Traditional masonry chimneys were designed and sized to vent very hot flue gases from old coal wood burning or low efficiency gas furnaces.

Venting hot water heater and furnace through chimney.

Consequences of improperly assembled vent pipes problematic chimney flue deteriorating chimney walls can be sometimes fatal fire and carbon monoxide poisoning are topping the list. Illustration above an unused chimney flue or masonry enclosure may be used as a passageway for the installation of the water heater vent pipe. Venting through existing chimney. The exhaust gas temperature of modern gas furnaces and water heaters is much lower than past appliances because much more heat is harvested so you waste less money up your chimney.

Atmospheric venting refers to a system in which exhaust from the water heater naturally rises out of the appliance s combustion chamber then travels up through a standard chimney style flue that. That s a sign that hot gases are backdrafting toward the unit. Proper furnace water heater venting is an extremely important issue which depends on the performance of the house chimney chimney flue or other exhaust assemblies. All water heater venting systems use a vent duct or pipe also called a chimney or flue to bring exhaust gases from the water heater to the outdoors.

When venting two appliances separately into a common chimney always install the smaller flue pipe appliance with lowest gph input at a higher point into the chimney than the larger flue pipe for the appliance with the largest gph input. Refer to figure 2. In some homes gas water heaters also vent into chimneys. When venting a gas water heater to a chimney be aware that holes in the chimney can prevent a good draw on the water heater causing downdrafts and presenting the risk of carbon monoxide poisoning.

Two gas fired appliances such as a water heater and heating boiler may be vented into the same flue if your local jurisdiction approves of that installation. The area around the flue piping should be sealed where it enters the chimney. The duct may be metal or plastic depending on the type of vent system. These should be tested as well especially if you see melted or melting plastic grommets on the side of the water heater.

A backdrafting water heater is arguably an even bigger problem than a backdrafting furnace. Before connecting a vent to a chimney make sure the chimney passageway is clear and free of obstructions. Water heater ducts may lead directly outdoors or they may tie into a larger vent duct that also serves a gas or propane furnace or boiler in the home.