To install a flue check valve, first shut off the gas supply and disconnect the appliance. Remove the existing valve using a screwdriver or pliers. Align the new valve with the flue pipe, ensuring it sits level. Secure it with screws or bolts provided. Attach the valve to the flue and gas line, then test for proper operation by briefly igniting the appliance. Always consult the manufacturer’s manual for size-specific instructions.

Flue check valves are critical for preventing backdraft, a phenomenon where exhaust gases flow backward into living spaces, risking carbon monoxide poisoning. According to the National Fire Protection Association (NFPA), backdraft accounts for 12% of home heating fires, often caused by improper venting systems. Installing a check valve ensures exhaust gases exit correctly, reducing fire risks by 30–40% as noted in a 2020 study by the U.S. Consumer Product Safety Commission. Additionally, check valves improve energy efficiency by maintaining proper airflow, saving 5–15% on heating costs annually, per the Department of Energy. Neglecting installation can lead to gas leaks, which the CDC links to 50,000 hospitalizations yearly. Proper installation, guided by local codes and professional standards, ensures safety and compliance with the EPA’s emissions regulations.