Immediately after turning on the gas in a new system, what should be done?

After turning on the gas in a new propane system, the most critical step is to check for any leaks. This assessment is essential to ensure the safety and proper functioning of the system. Typically, this involves visually inspecting connections and joints for signs of gas leakage and may also include the use of a leak detection solution to bubble test any suspected areas. Ensuring there are no leaks immediately reduces the risk of fire or explosion and confirms that the system is operating as intended.

The other options, while they may be relevant in different contexts, do not address this immediate safety concern. Pressing could imply operation or adjustment of a component, calibrating generally refers to adjusting equipment to enhance accuracy, and lubricating is typically associated with maintenance of mechanical parts, none of which are as crucial as checking for leaks right after gas activation.