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 1-sq.-inch for every 4000 Btu rating of water heater is required inside the higher and reduce 12 inches with the enclosure. Our encounter was excellent! https://aaronf443xmb0.estate-blog.com/profile