Hot Water Heater Backdrafting

Last week i blogged about how to determine if a water heater is backdrafting.

Hot water heater backdrafting.

Fuel fired water heaters boilers wall heaters and furnaces are designed to exhaust the by products of combustion to the outdoors through a flue. If a water heater backdrafts it means that potentially hazardous exhaust gases are coming back into the home. Backdrafting can have many causes but it is most commonly due to poor vent design or installation and or an imbalance of air volume in the home. The most common problem associated with water heater venting is a condition called backdrafting in which exhaust gases from the water heater fail to exit the home via the vent and instead end up in the house.

This problem affects mainly the atmospheric gas type water heaters that use the natural convection for the removal of the products of combustion known as the exhaust gases. Causes and recognition backdrafting is a potentially fatal health hazard connected with the presence of heating appliances that use atmospheric draft to exhaust toxic combustion gasses to the home exterior. This happens when the exhaust gases from an atmospherically vented water heater spill out into the room rather than safely leaving the house through the vent. Another way dangerous backdrafting can occur is through improperly configured flues or flue blockages warns gromicko.

The main reasons for the backdrafting at the water heater are the poor vent installation and the obstructions found in the vent pipe. A water heater backdrafts when the exhaust gases from an atmospherically vented water heater spill out into the room rather than safely leaving the house through the vent. Some water heaters will be right on the brink of backdrafting even with a proper installation and all it takes is a single bathroom exhaust fan to pull enough air out of the house to make the water heater backdraft. These heating devices are identified by the presence of a draft hood also called a draft diverter.

When homeowners replace older furnaces with more efficient models that don t use the chimney to vent gas water heaters are often left as the only device venting into the chimney which is now oversized for the water heater alone. Backdrafting at a water heater is a common defect identified during home inspections and it s almost always a condition that the homeowner or occupant is not aware of. Exhaust gases contain carbon monoxide and high levels of moisture so this is always a condition that should be corrected.