Commercial Architecture May 2017 - 59

PROJECT

hvac

HOT-WATER WOES

For more than two years, the hotel battled domestic
hot-water issues. As it turned out, a large hydronic
valve was used for the original system. The misapplied
valve had a 120-sec. response time and couldn't actuate quickly to keep up with the changing water pressures within the hotel. Because of the valve's sluggish
response time, every time something would go wrong
with the pumps, heat exchangers, or storage tanks,
the entire domestic-hot-water system would require
a time-consuming recalibration. Maintenance was
required routinely and became a constant source of
disruption for the engineering staff.
"More or less, when maintaining the domestic water system, we had to isolate the entire piped network,
shutting it down completely," explained Brinkerhoff.
"Whenever the hot-water mixing valve opened or

Domestic-Water System Risks
Legionella: According to the Centers for Disease Control, Atlanta, proper maintenance of water-distribution
systems is key to preventing illness from water-borne bacteria such as Legionella. CDC statistics show that 8,000
to 18,000 people are hospitalized with Legionnaires' disease in the U.S. each year. Managers of commercial and
institutional facilities know that selecting and controlling proper water temperature in their storage and delivery
systems plays an important part in preventing germ growth.
Scalding: Uncontrolled and unmonitored water-distribution systems can create high-temperature scalding
hazards in bathtubs, sinks, and showers. Digital mixing systems make it easy to select and set safe water temperatures
for large domestic water systems.
Thermal Shock: The thermal shock of a rapid and uncomfortable change in shower water temperature can cause
a fall or serious injury. With digital mixing, stable mixed water is delivered to ASSE (American Society of Safety
Engineers, Park Ridge, IL)-listed thermostatic point-of-use devices (shower or sink valves) to minimize this risk.

modulated, the entire system would flood with cold
water."
Instead of being able to run the hot-water storage
tanks at 150 F, facility engineers had to turn the tanks

and I was able to see it in operation and speak to facil-

technology-testifying that it only took seconds for hot

down to produce storage temperatures of only 125 F.

ity managers who more than vouched for the system."

water to get to taps-I was sold," added Brinkerhoff.

Also, the capacity of hot-water storage plummeted.
ENOUGH IS ENOUGH

Facility managers and engineers came together

What he learned was that the hotel now had a

The Powers IntelliStation touchscreen control op-

fast-responding, safe, and clean domestic-hot-water

erates a three-way valve through a high-speed actuator

system that delivered hot water on demand.

to precisely maintain the selected outlet water tem-

"After hearing maintenance managers validate the

perature. Temperature and pressure sensors are includ-

and decided to replace the entire hot-water system.
Brinkerhoff was appointed to act as liaison between
hotel ownership and the installing contractor. Having
worked with him in the past, Brinkerhoff called on Ian
Walters, project manager for Kansas City, MO-based
Lexington Plumbing, a mechanical contracting firm
specializing in commercial and industrial work. Walters had a solution in mind shortly after speaking with
Brinkerhoff about the hotel's water issues.
"Ian and I had this discussion about the hotel's domestic-water system, and that there are just so many
dynamic changes with the pumps and water pressures,"
said Brinkerhoff. "We knew what the hotel needed
was a smarter, more responsive valve-especially considering that the guests in all 384 rooms had very different schedules."
Months earlier, Walters had learned about a digital
mixing valve made by Powers, a Watts Brand, North
Andover, MA.
"They make a smart-delivery solution for mixing
domestic water in a hot-water recirculation loop," explained Walters. "It's called IntelliStation. Shortly after learning about them from our rep, we installed one
at a large hotel on the other side of town. There, we
exceeded the expectations of facility managers-a
strong confirmation that the technology worked well."
Walters didn't want Brinkerhoff to just take his
word for it. He wanted to show him first-hand.
"I went with Ian to another Marriott hotel that had
similar hot-water issues," Brinkerhoff said. "They'd installed an IntelliStation digital mixing system there,
CIRCLE 225

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Table of Contents for the Digital Edition of Commercial Architecture May 2017