By Steve Spaulding
Of Contractor's Staff
BROOKLYN, N.Y. — Kal Rotenberg, owner and chief designing engineer of Iceman Mechanical, describes the Lorimer Street Synagogue as a "funny, lopsided corner property just where Lee Street and Lorimer Street meet."
It's an Orthodox synagogue in a primarily Jewish Orthodox community — which posed a certain set of requirements, as well as a few interesting challenges when it came to designing its plumbing and heating system.
In addition to the standard institutional heating and plumbing needs of any moderately sized building, the Lorimer Street Synagogue required a Mikvah, a traditional Orthodox Jewish bath used for ritual purification. It consists of a rainwater-fed immersion pool (the water for it has to come from a natural source) and a bank of 14 showers. So, essentially the synagogue contains its own bathhouse.
The challenge is one of demand, not just for the synagogue itself, but for the entire area.
"There's a problem we have in our world," Rotenberg explained, "which is on Friday, on the sabbath, we don't use hot water."
The act of heating the water is considered cooking, which is work and so forbidden.
So between 2 and 4 p.m. on Fridays (the sabbath starts at sunset) there's a rush period where every fixture in the neighborhood is going. Mean pressure in the area often drops as low as 15 to 25 PSI at street level — even lower on upper levels.
"Most townships, they do have an evening rush hour, but it's spread out over four or five hours," Rotenberg told CONTRACTOR. "It doesn't compress into two hours like it does for us. And we have to design for it, boost the systems. We have to have the Btus to back it up, even when the gas pressure is dropping."
To help tackle the job, Rotenberg turned to Moses Fischmann, master plumber and owner/operator of ENY Mechanical.
"I do work with other people too, not just Moses," Rotenberg said, "but I prefer to work with him because I know that when I give him a diagram that's what's going to happen."
To power the system, Rotenberg used a combination of a rooftop package unit and an array of Laars Pennant boilers in the mechanical room with an outdoor reset. A Caleffi three-way valve controls the flow of water through coils in the air-handling units. The system also includes radiators and, in the bath area, an in-slab radiant heating system.
"The Caleffi is a very nice thing," Rotenberg said. "I've got gas separation, condensate separation and hydraulic separation all in one shot. We use that for almost all our jobs now."
The combination of the boiler and the rooftop units ensure the system has enough capacity.
"The overwhelming majority of our load is a high-temperature load," Rotenberg said. "It's 180°. So the better way to go, instead of making the boilers nuts, is to use a variable-speed pump in a loop. We have a radiant manifold and we have a closed T-loop between two manifolds with a Taco variable-speed pump set-up."
Next, to help deal with the low incoming pressure, ENY Mechanical installed Conbraco's Apollo 34 HL thermostatic mixing valves, a single assembly that's able to control multiple-outlet shower and sink installations. Temperature is controlled to within 5° F of the set point.
To ensure safety and reliability, the low-water cut-off shuts down the entire boiler room to help protect the pumps.
"A lot of people don't do that," Rotenberg explained, "so the pumps will run dry until they're dead."
Rotenberg said the job "went together like a dream." The heating and plumbing work is only a few weeks away from completion. All that was left to do was work out some control issues.
"With these things, I usually use a tekmar 268," Rotenberg said, "but this system is so simple I may just let the boilers phase themselves. These low-mass boilers, if you stage them externally, it's sometimes a problem because they can tend to overshoot."
The result is a system that uses some of the latest technology to facilitate some of the oldest religious observances. Rotenberg is so proud of the results he almost can't wait for the inspectors to show up.
"Everything," he said, "is just so pretty."