Below, Figure-1 shows a Sediment Trap for a Gas Water Heater.
Figure-1: Improperly installed Sediment Trap
Note that the Sediment Trap is improperly installed. The flow of the gas does not change direction at the trap but flows across the trap. In this configuration any debris in the gas would not be caught in the trap.
To fix this the elbow to the left should be removed and replaced with the existing “T” fitting so that the sediment trap is below and the gas flow turns to the water heater.