What action should be taken immediately after turning on the gas in a new system?

After turning on the gas in a new system, the immediate action should be to check for leaks to ascertain that no gas is escaping. This is a crucial safety measure to prevent hazardous situations, such as fires or explosions. Gas leaks can occur during the installation process, and ensuring that all connections and fittings are secure is vital for the safety of the system.

Conducting a leak check typically involves using a specially formulated leak detection solution or soapy water, which will create bubbles at the site of a leak. If any bubbles form, it indicates that gas is escaping, and the issue needs to be addressed immediately. This step should be performed before the system is put into operation.

The other options suggest actions that do not appropriately address immediate safety concerns. Leaving the system alone for 24 hours does not ensure safety; reporting to local utilities is necessary for other types of emergencies but not for initial checks; and testing with an open flame poses a significant danger as it could ignite any escaping gas. Therefore, checking for gas leaks is the correct and safest protocol to follow immediately after turning on the gas.