Direct Vent Water Heater Venting Requirements

When determining the installation location for a direct vent water heater snow accumulation and drifting should be considered in areas where applicable.

Direct vent water heater venting requirements. Above the air intake inlet. The natural gas fueled water heater shown at page top is improperly vented lacking the recommended minimum 12 of vertical rise before the elbow and vented directly into a large masonry flue where it cannot develop adequate draft. Never operate the water heater unless it is vented to the out doors and has adequate air supply to avoid risks of improper operation explosion or asphyxiation. In addition to venting gas and propane water heaters need an air supply for combustion.

See figures 4 through 8 and items below. Atmospheric venting works on the principle of hot air rising. For this reason common venting configurations are no longer allowed in some code jurisdictions where direct venting or power venting of water heaters is now mandatory. 18 minimum in all directions from any obstruction that may interfere.

Vent adapter is needed to connect the water heater which is tankless to the exhaust hose. Select either an adapter of three inch or an adapter of four inches depending on what water heater model you decide. A direct vent system pulls in air from outside and then vents the exhaust through a horizontal pipe. For non direct vent applications that is side wall venting only the required clearance is 7 feet.

Warning vent termination must not be within 4 feet of any items such as gas meters gas valves or other gas regulating equipment. In direct vent applications this clearance distance must be in compliance with local building codes the requirements of the fuel gas supplier for the heating appliance in use and the appliance manufacturer s instructions. This heater installation may be unsafe. The water heater must be properly vented to the outdoors.

Illustrations of proper gas fired water heater venting using type b double wall vent pipe through a roof above or through a chimney below include details for the flue vent connector such as the requirement of a minimum vent connector upwards slope of 1 4 per foot of horizontal run. The vent outlet must be installed a minimum of 12 in. This venting may either be dedicated to the water heater or can be shared with other atmospheric vent appliances such as a furnace. All emission of liquid or gas water heaters which are tankless needs vent pipes made of stainless steel and approved by ul.

The venting must be vertical or upward sloping so that the hot exhaust rises up through the venting to exit your home.