Gas Water Heater Exhaust Ducting

In this case the exhaust gases backdraft into the home.

Gas water heater exhaust ducting.

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. Backdraft means the exhaust gasses move downward in the exhaust pipe. A water heater whose exhaust vent is inadequate due to insufficient chimney height or worse blocked by an improper termination is unsafe regardless of whether or not co is detected. It s easier to run the vent if you install a power vented type of natural gas or propane water heater.

The duct may be metal or plastic depending on the type of vent system. With a vent pipe that is too large the water heater does not produce enough heat to sufficiently warm the vent pipe to get water heater exhaust gases to rise out of the home. Most have a natural draft type of vent where the hot waste gases rise through an open draft diverter and into metal pipes which eventually lead to the outdoors. Inside the unit this air passes over a copper heat exchange coil and transfers some of its heat to the refrigerant flowing through the coil.

Then the air now cooled is expelled from the exhaust side of the appliance. The venting system must be correctly sized to handle the total btu input of the water heater. On top of natural draft gas water heater in its center section right above the water heater vent you should have a draft hood installed. 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.

This process raises the temperature of the refrigerant and eventually the water in the tank. This type of venting system is different from what you see on most gas water heaters. 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. Atmospheric gas water heaters vent their exhaust through a vertical or upward sloping metal duct vent to exit the home.

This article series describes proper ventilation details for handling the exhaust from gas fueled water heaters both lpg or propane and natural gas. It sits on 3 4 short legs sometimes secured to the water heater top plate with screws or depending on design has its legs shaped like pins or hooks at the end inserted into the holes in water heater top cover. Even a small change in a building opening or closing a door or window can lead to illness or to a fatality. The n the gasses end up inside the home near.