School DHW systems built to last with Navien tankless water heaters Even in times of peace and plenty, building and occupying a modern school is an endeavor for any community. Building three at once, even with ample years of planning, is a challenge of monolithic proportions. That’s just what the rapidly growing town of Moore, Okla., did immediately on the heels of the F5 tornado that claimed lives and ravaged the town in the spring of 2013. And they did it in nine months. “The town reeled in shock for a few days,” says David Elliott, the school district’s plumbing foreman. Despite miles of garbage and flat wasteland that had once been a beautiful suburban neighborhood, the district planned to swiftly rebuild the two demolished schools and continue with existing plans to construct a third. DEDICATION AND KNOW-HOW “For nine months our guys worked 60-hour weeks to install plumbing and HVAC systems across the district,” says Randy Hunter, owner of Hunter Mechanical in Oklahoma City. The city needed three new schools, fast, but couldn’t afford to sacrifice efficiency, sustainability and longevity in the name of expediency. The key to overcoming countless obstacles was working harder, working smarter and using the best products for the application. When it came time to install plumbing components, simple, yet superior systems cut down on install time. Instead of one central mechanical room housing all DHW production equipment with hot water lines running throughout the building,tankless water heaters were installed in close proximity to all the main points of use: kitchen, janitorial closets and bathrooms. There are 16 Navien NPE-240 units throughout Plaza Towers Elementary, and the other schools in the district use the same approach. Four serve the kitchen, while the others are paired together in smaller mechanical spaces, primarily in closets between the boys and girls bathrooms. “You simply click a communication cable from unit to unit and press a few programming buttons on each unit,” Hunter says. “There’s no external control needed. Just turn them on and walk away. It saves hours.” Above the drop ceilings 2-in. PVC venting ties into a common pipe so only two penetrations are made in the roof, thus saving installation time. With Oklahoma’s harsh groundwater — at more than 10 grains of hardness per gal. — tanktype water heaters at the original schools failed rapidly. In 2010, the district started replacing tanks with wall-hung, condensing tankless units. “Over the years we tried a variety of different gas-fired tankless water heaters,” Elliott explains. “Units with copper heat exchangers would last no more than nine months before corroding. We settled on the Navien units because of its stainless-steel heat exchanger.” SOLID SCHOOL SOLUTION For an elementary school application, Elliott finds tankless technology can’t be matched. The units that serve the bathrooms and common areas are all set back to 110° F, while the units in the kitchen heat water to 140° before sending it to the wash-room and food-prep areas. “There’s no better way to ensure safe water delivery than when the unit doesn’t even produce water at a dangerous temperature,” Elliott says. “And because there’s no body of warm water, the presence of Legionella bacteria isn’t even a consideration.” Another added benefit to tankless technology is the floor space saved. The school was spending about $200 per sq.-ft. on the new buildings. Considering that a single commercial-sized water heater needs up to 25 sq. ft., eliminating a single tank means a savings of nearly $5,000 during construction. “The new schools were completed in plenty of time for the 2014-2015 school year,” Elliott says. “Since then, we’ve not had a single issue with any of the water heaters or any real challenges with the HVAC systems, either. Our schools are built to protect our most valuable asset: the kids. And barring another direct hit from a tornado, so are the systems inside.” www.navien.com
Published by SupplyHouseTimes. View All Articles.
This page can be found at http://digital.bnpmedia.com/article/Navien/2319865/280186/article.html.