What should you ensure when installing a gas appliance using a masonry chimney?

When installing a gas appliance using a masonry chimney, it is essential to ensure that the chimney is approved and inspected. This requirement is critical for several reasons. First, an inspected chimney ensures that it meets safety standards and is free from structural damages, blockages, or any conditions that could lead to dangerous situations like carbon monoxide leaks or fires. An inspection verifies that the chimney is properly sized for the appliance being installed and that it has the correct flue configuration to allow for safe exhaust of combustion gases.

Additionally, building codes and manufacturer requirements typically stipulate that any chimney used with a gas appliance must be in good working order and compliant with local regulations. This compliance is vital for maintaining the appliance's warranty and ensuring the safety of the users. Proper verification through inspection can also help identify whether the chimney needs any repairs or upgrades to function correctly with a new gas appliance.

The other options highlight procedures that could lead to unsafe installations or non-compliance with regulations. Hence, ensuring that the chimney is approved and inspected is not just a best practice but a necessary step in the installation process.