Mr Fix It Plumbing 4320 Atlantic Ave #230, Long Beach, CA 90807 (562) 988-2454 http://www.mrfixitplumbing.com/ A combustion air opening in an exterior wall of one-square-inch for every 4000 Btu rating of water heater is required in the higher and lower 12 inches on the enclosure. When they are dropped https://maps.app.goo.gl/JAqevuQwVnnK5SJu6