The rarely noticed sediment trap, or drip leg, is an important part of any gas appliance. These small pipes that appear to be extensions of the gas line serve the purpose of collecting sediment, debris, and other impurities that come through the gas line, catching them before they enter the appliance. This keeps the burners clean and prevent further problems associated with impurities continuing past the sediment trap.

Sediment trap on a furnace.

For sediment traps to be most effective, it should be installed at a 90-degree angle change of direction of gas flow. This helps to keep sediment from simply flowing directly over the trap. It should also ideally be installed after the shut off valve, to allow for safe cleaning. If it is installed before the valve, cleaning becomes more difficult since gas would still be flowing.

In conclusion, sediment traps are an important part of gas appliances and help to facilitate easy cleaning. While the absence of these traps is not necessarily a dangerous condition, they should be present for the safest operation of gas appliances.

No sediment trap on the gas line to this water heater.