Northern Ohio Plumbing Co., Inc.’s (NOP’s) creative approach to mounting A. O. Smith tankless water heaters saved the contractor installation costs and saved floor space in the mechanical room. The water heaters themselves and the layout of the mechanical room promise to make maintenance a snap. The owners of the Holiday Inn-Cleveland Clinic, which opened in May, were inspired to use tankless water heaters because of the nearby Cleveland Clinic’s interest in energy efficiency and sustainability. The 199,000-BTU A. O. Smith units deliver a uniform energy factor of 0.93 and, working together, provide more than enough hot water for the guests and staff of the hotel. Ultimately, NOP put in 29 wall-mounted A. O. Smith ATI 540H-N fully modulating condensing tankless water heaters.
“We’ve done a number of tankless installations in Ohio, but never anything of this scope,” said Kevin Conyngham of LIBB Company, Inc., the manufacturer’s representative responsible for coordinating the project.
Located adjacent to the world-renowned medical center, the new Holiday Inn-Cleveland Clinic is designed to serve the many people who visit or serve the sprawling clinic campus. The hotel does not experience the type of morning “rush hours” that most hotels do, during which guests demand significant quantities of hot water for showers or bathing from 6 a.m. to 8 a.m. Suppliers to the nearby clinic, visiting physicians, and family members of patients make up the bulk of the hotel’s guests, and they tend to arrive and depart at all hours. The A. O. Smith units can meet their hot water needs throughout the day and night.
The 29 units are divided into two zones, Jim Roddy Jr., NOP president, explained. Eleven units supply 140° F hot water to the laundry and kitchen, while 18 units serve the 284 guest rooms with 110° F hot water. Not surprisingly, the laundry requires the most hot water, although the Mocé Café and Bar and the hotel’s event facilities also demand ample quantities. The A. O. Smith tankless water heaters’ modulating capability means the units can ramp up to meet peak demands while saving energy and costs for the owners.
The NOP team identified a number of creative approaches that saved space and reduced cost during the installation. The original specification called for installing the tankless units on a prefabricated rack system in the mechanical room. Instead, Ben Welton, NOP’s foreman for this project, came up with a unique wall-mounted configuration that saved mechanical room floor space. He staggered the units to make the most of the available walls, which better accommodated the water heaters’ piping and venting. “The finished job is nothing like the original drawings,” Conyngham noted.
NOP also maximized the venting capabilities of the tankless units. The contractor installed one large plenum that branched into individual air intake pipes to supply the 29 water heaters with fresh air. This method required creating just one hole in the mechanical room’s exterior wall. The units’ exhaust vents are collected into a set of four large exhaust vents that exit the building through one wall. PVC water lines from each of the tankless water heaters lead to a series of risers; one pair of risers serves each guest floor.
The modulating capability of the A. O. Smith condensing tankless water heaters eliminated the need for a hot water storage tank normally used in a hotel application. Roddy said that NOP tested the system, running multiple showers on multiple floors at the same time, and the water heaters were able to keep up with the demand.
The A. O. Smith 199,000-BTU tankless units are rated to deliver a maximum flow rate of 10 gallons of hot water per minute. Even during Cleveland’s cold winters, the water heaters can deliver a minimum of four gallons of hot water per minute or seven gallons of blended water, Conyngham pointed out.
“The nice part is the redundancy of the system. If one unit requires maintenance, you don’t have to shut down the system, and the hotel will still have hot water,” Welton noted.
For more information, visit www.aosmith.com.