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-sq.-inch per 4000 Btu rating of drinking water heater is necessary within the upper and reduce 12 inches of the enclosure. We realize that plumbing https://www.google.com/maps?cid=4067949459714107514