What is the correct response to the statement: "The chimney must be left unlined when venting into an unlined chimney?"

The statement "The chimney must be left unlined when venting into an unlined chimney" is false. Proper venting practices dictate that when a venting system connects to a chimney, it should not remain unlined. Even if the chimney itself is unlined, best practices require that it be lined properly to ensure safe and efficient venting of combustion gases.

An unlined chimney can lead to a range of issues, including deterioration from corrosion, insufficient draft, and the potential for dangerous exhaust gases to escape into living spaces. The installation of a proper liner helps to contain these gases and prevent leaks, ensures better draft performance, and improves overall safety. Hence, proper venting standards affirm that both the chimney and the vent should be appropriately lined to ensure a secure and compliant system.