What is the first action to take with the gas line before servicing a gas furnace?

Shutting off the gas supply is critical before servicing a gas furnace because it ensures the safety of the technician and anyone nearby. Gas furnaces pose inherent risks due to the potential for leaks, fires, or explosions when working with gas components. By turning off the gas supply first, one eliminates the hazard of inadvertently allowing gas to escape while servicing the furnace.

This action is a basic safety protocol in HVAC practices that prevents accidents and ensures that the work can be done safely without the risk of ignition or exposure to harmful gases. After the gas is shut off, other procedures, such as testing for gas leaks or cleaning components, can be performed safely.