Rooftop tankless water heater array has California chefs at the top of their games
Hot water to order.
As longtime residents of California, Travuth Mock, P.E., and David Guthrie, P.E., know the City of Santa Ana incredibly well.
Now the team from Riverside, Calif.-based Empire 3 Consulting Engineers firm — Mock, the company’s president; Guthrie its plumbing and mechanical engineer — can take in some hearty meals in the same facility where they provided an expansive plumbing design.
Santa Ana’s 4th Street Market is a 30-year-old, two-story, 30,000-square-foot facility designed for young chefs lacking the opportunity to go into business themselves to rent space and prepare their food for the region’s residents — from millennial to senior. The facility, owned-and-operated by Ryan Chase of S&A Management, was inspired by other landmarks such as Pike’s Place in Seattle and the Grand Central Market in Los Angeles.
“I have been there seven or eight times since it opened and the place is packed,” Mock says. “There are a lot of young and old people hanging out there. Santa Ana is a revived area. There are more jobs coming.”
Guthrie adds: “Santa Ana is an integral part of greater Southern California. This building is in downtown Santa Ana. In the 1920s, 30s and 40s this was downtown. This building is a revitalization of that particular block. There are a lot of businesses there now.”
The 4th Street Market opened in February 2015 and has 15 different “artisan” food vendors — including eateries such as Chunk-N-Chip and the Noodle Tramp — that work in about 300-square-foot sections. Then there is a collection of 10 commercial rental spaces known as the East End Incubator Kitchens. Each Incubator Kitchen is self-contained with the public able to view them from the street. They can be rented by the hour, day or month and have access to 4th Street Market’s 8,000-square-foot basement with commissary, dry and cold storage, and packing/labeling room.
All the chefs receive the opportunity to showcase and test-market their products at the Alta Baja Market (inside the 4th Street Market), which carries cheeses, beer, wine and bakery items. All these spaces make up the 44-ft. by 31-ft. first floor, making Guthrie’s plumbing and mechanical design a unique challenge. The first course of action was to get outside and up on the roof.
Space it out
Mock notes Empire 3 has worked on multiple projects in downtown Santa Ana with S&A Management throughout the last 10 years. That relationship helped the consulting engineer firm land the project with S&A Management.
Chase, Guthrie and Mock worked together to maximize the rental space and found that creating an array of tankless water heaters on the roof would fit the bill. Because of the year-round warm temperatures and sparse rainfall, Guthrie had the blessing to create a mechanical operation out in the open.
Local inspectors also approved the use of tankless water heaters for the 4th Street Market, making S&A’s decision to forge ahead easier.
“Because tankless technology has improved, our local health department is more accepting of their use,” says Jeff Beddow, S&A Management’s construction manager.
Therefore, 22 Noritz tankless water heaters were tabbed for a rooftop array at the 4th Street Market.
Guthrie and the project’s plumbing contractor, Huntington Beach, Calif.-based Crandall’s Plumbing, specified and installed Noritz NC250-DV units that feature a thermal efficiency of 84%, flow rates that vary from 0.5 to 11.1 gpm and gas consumption from 11,000 to 250 Btu/h.
S&A Management’s initial hopes were for a boiler and storage-tank design, but the logistics for that route proved to be too challenging. Additionally, S&A Management wanted to meter each food tenant’s hot water consumption to offset the company’s operating costs.
Because of the space restraints in fitting all the kitchens, eight of which are in the middle of the facility, Guthrie placed the requested meters up on the roof with the Noritz units.
“That had to be up on the roof,” Guthrie states. “There was not another way to engineer it out.”
Guthrie has worked on many projects with Noritz. He states a storage-tank type would not have worked for the 4th Street Market because of its weight and the stress it would put on the facility.
“I have done a lot of projects with Noritz,” Guthrie says. “They are very popular. They don’t require storage tanks and that keeps the weight off the roof. The tankless was the absolute perfect answer.”
Running the course
To protect the Noritz array from potential damage from an earthquake — although rare, still an important concern in Southern California — Crandall’s mounted and secured the water heaters to a Unistrut rack system. It took some trial and error to get the system perfected since the company had not built one before.
“When something did not immediately work as we envisioned it, we improvised and adjusted,” says Sam Crandall, co-owner of Crandall’s Plumbing. “That was true of our work on the rack, like everything else. We had never built a tankless rack before so we had to figure it out — and we did.”
The pipe runs at 4th Street Market were a tough challenge for a number of reasons. First, copper tubing was used for the water lines and galvanized steel pipe for gas. The pipe covered 4,000 square feet of roof space and runs to one of five chases that lead from the roof through the vacant second floor to the kitchens and vendors on the ground floor.
Guthrie recalls how the water at 4th Street Market came in from the back of the building, a patio area for patrons. The water then went up to the roof to the water heaters and back down throughout the facility. Outside the market, there was a small building that housed a traditional tank water heater.
“That was for the toilets and faucets. That usage was covered by the property owner,” Guthrie adds.
Guthrie and Empire 3 applaud the work Beddow did as a property manager and job foreman, especially with the work he did in conjunction with the City of Santa Ana. Guthrie notes connecting the design to the city’s sewer system would have been more complicated without Beddow’s leadership.
“We had elevation issues regarding how to get that much sewer system piping out to the main city system,” Guthrie says.
From the roof of the 4th Street Market to the ground floor was not a straight line so the design and installation required adjusting the line in whatever direction necessary to make the final connection to the fixture. The installation of the Noritz tankless water heaters took one week, but the line runs took nearly one full month.
“We did no prefabrication on this project because we are not a prefab shop,” Crandall says. “Everything had to be done in the field. We’d see a problem, put our heads together, sketch something out and then go for it. In the end, it came together nicely.”
There is refrigeration equipment for tenants to store their ingredients and food, but it’s in the basement of a building adjacent to the 4th Street Market. With the cold storage in the basement, Guthrie had to add in ventilation and plumbing for excess condensation.
Guthrie also specified a Daikin unit for the HVAC design for the 4th Street Market, which was fully air-conditioned. The amount of exhaust hoods that had to be specified was massive because of all the kitchens.
“It had to have makeup air,” Guthrie notes. “They were 100% outside air and there wasn’t any return air. That complicated the air balance problem of trying to exhaust and make up air.”
The Noritz tankless array has worked out and impressed S&A Management so much that the company installed the manufacturer’s units in two other Santa Ana restaurants.
“(They) provide a reasonable solution to the demands of the county health department and the state plumbing code,” Beddow states. “We also know tankless units are energy efficient for our tenants.”
Mock notes the currently vacant second floor of the 4th Street Market, where a college used to be, will become commercial retail space. Mock, Guthrie and Empire 3 are prepared to get back to work.
“I hope I left some room up on the roof,” Guthrie says with a chuckle.
This article was originally titled “Hot water to order” in the March 2017 print edition of PM Engineer.