Gas Hot Water Heater Venting

The photo below shows typical combined furnace water heater venting.

Gas hot water heater venting.

A water heater vent pipe can be used for this venting with a hot water heater vent cap for safety reasons. Two specialized types of water heaters direct vent and mechanical vent also called power vent are exempted from this code requirement. Make sure that the ventilation direct outside the house or else there is a chance of fire or explosion in the house. The process of burning of the gas is called combustion and it creates heat exhaust gases including highly poisonous carbon monoxide and moisture the water heater s ventilation system removes these byproducts from the home making it a critical safety feature.

The two pipe system might be further divided on the concentric pipe inside the pipe or two separate pipes and the vents can run horizontally vertically or combined. The venting system of the gas water heaters might consist of one or two pipes. With a replacement high efficiency furnace the existing vent pipe does not work for water heater only because the vent is too large. 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.

One problem you need to avoid is back drafting. Most tank type gas water heaters are atmospheric vent type and they are required to vent vertically and above the roof of a home. Back drafting is usually the result of an inadequate vent design. All water heaters that burn natural gas or liquid propane lp gas require a venting system.

You see this most commonly with atmospheric configurations and it means that your exhaust isn t leaving the home.