What is the Code for Gas Water Heater Ventilation? - A Comprehensive Guide

Gas water heaters are essential for providing hot water in homes and businesses. However, if your gas water heater has been exposed to flooding, it is important to take the necessary steps to ensure that it is properly vented. This article will provide an overview of the codes and regulations that must be followed when installing a gas water heater, as well as the potential risks of inadequate ventilation. According to the National Combustible Gas Code or, in Canada, the Natural Gas and Propane Installation Code, there are specific procedures that must be followed to put equipment into operation. The table below is adapted from the AO Smith Gas Water Heater Owner's Manual for FSPH-75 270 Series gas models.

It is important to note that inadequate ventilation, lack of the recommended minimum vertical lift of 12 degrees before the elbow, and venting directly to a large masonry chimney can all lead to problems with air flow. The lower BTUH of a gas water heater (compared to a furnace or heating boiler) will often not be able to heat the inside of the chimney enough to generate an air current. Burn marks are an indicator that an upside-down current has occurred in this gas water heater. If you notice this, it is important to check for obstructions in the air holes or flue gas. If you are unable to move the burner outdoors, it is important to consult with a professional who can help you find a solution. It is essential that all safety regulations and codes are followed when installing a gas water heater.

This includes ensuring that there is adequate ventilation and that all components are UL certified. Failure to do so can lead to serious safety risks. If you have any questions or concerns about your gas water heater, it is important to consult with a professional who can provide advice and assistance.