Furnace And Water Heater Venting

The lower btuh of a gas water heater compared with a heating furnace or boiler will very often be unable to heat the chimney interior sufficiently to develop a draft.

Furnace and water heater venting.

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. In contrast modern high efficiency condensing furnaces exhaust much cooler gasses and need only plastic pipe materials such as pvc cpvc or abs for their exhaust vents some high efficiency furnaces also include a plastic pipe for intake area and all types. The vent for your recently orphaned water heater may not have been checked by the furnace installer. Power vent water heaters have quickly become the standard for newly constructed homes equipped with built in fans that push the exhaust gas out of the vent through a powered fan.

The result is a back draft of combustion products out of the water heater s draft hood and into the building. As far as sealing off the ventilation in your crawlspace very bad. The conditions explained in this post also apply to the wood burning appliances. The photo below shows typical combined furnace water heater venting.

This is called a common vent configuration. 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. You have 3 gas burning appliances that must have a constant fresh air supply to support clean and complete combustion process. Gas water heater vent codes standards.

Because of their unique construction power vent water heaters are virtually impossible to backdraft. In many cases the exhaust from the larger appliance heats up the common vent improving the flow of the water heater vent. Many building codes mandate that once modified or changed all fuel burning appliance vents must be sized according to code. Consequences of improperly assembled vent pipes problematic chimney flue deteriorating chimney walls can be sometimes fatal fire and carbon.

It carries the solution down the chimney furnace water heater vent pipe and evaporates leaving the salt deposits on surface joints. High e furnaces have separate venting. With a replacement high efficiency furnace the existing vent pipe does not work for water heater only because the vent is too large.