What component in a gas system directly interacts with the appliance?

The appliance shut off valve is essential in a gas system as it serves as the primary control point for gas flow to the appliance. This valve allows a technician or homeowner to safely stop the gas supply to the appliance for repairs or maintenance without affecting the entire gas system. It is installed very close to the appliance, enabling easy access for operation.

While the gas meter measures the volume of gas being consumed and is vital for billing purposes, it does not directly interface with the appliance itself. The riser is a section of vertical piping that conveys gas from underground lines to the surface, essentially serving as a transport mechanism rather than a direct interaction point. Piping joints are crucial for connecting different segments of the gas line, but they also do not interact with the appliance directly.

Thus, the appliance shut off valve is the only component listed that provides a direct functional connection to the appliance, ensuring both usability and safety in gas operations.