Questions about sediment traps at meetings and reports from the field have indicated a need to review some basic installation practices for gas appliances that relate to minimizing the possibility of controls becoming contaminated by foreign material. These questions also have indicated a lack of understanding about the purpose and benefit of a sediment trap. There are a variety of circumstances by which contaminants can be introduced into the house gas piping systems. These circumstances range from the threading of gas pipe to unexpected chemical reactions on the interior of the piping occurring sometimes after the systems is in use. Regardless of their origin, if contaminants do get into a gas control they can cause significant problems. As an example, if some contaminating particles are deposited on a valve seat they may prevent the valve from fully closing and gas leak may occur. A properly constructed sediment trap is a simple, inexpensive device that diverts and collects contaminants in the gas stream, thus keeping them out of the gas control.
Install a sediment trap as close as possible to the inlet of the appliance as the time of installation. This is REQUIRED by all furnace and water heater manufactures as well as the National Fuel Gas Code. The trap shall be constructed to change the direction of the gas flow be 90 degrees.
Keep the supply piping clean. It should be free of foreign materials, oil, water or other contaminants. The best practice is to connect the gas piping immediately upon installation to prevent foreign material from entering the gas system.