At Oklahoma University, the drive for excellence has a long and proud tradition both in the classroom and on the football field. Lesser known however, is the university’s constant drive toward excellence and efficiency in its building operations. That’s why during a recent retrofit of its domestic hot water equipment, UA selected the Heat-Timer® ETS (Electronic Tempering Station) as its choice for master mixing and control.
With over 30,000 students on campus, Oklahoma University has multiple on-campus dorms including the twin 12 story buildings of the Couch and Walker Centers. These buildings are a focal point of student housing located in the center of the campus. As is common in high rise dormitories, the domestic hot water system includes steam to water exchangers and a master mixing valve.
UA Facilities Team Confronts A Hot Problem
Over the years the domestic hot water system in these (and other) buildings at OU, have required costly maintenance and repairs while still not providing the consistent hot water delivery required for safe use.
“The prior mixing valves were requiring a significant amount of maintenance,” notes Casey Yost of Federal Corporation out of Oklahoma city, who spearheaded the Heat-Timer® solution. “They were having to rebuild and replace the thermostatic mixers regularly, and the control head of the original package was failing.”
This was of course, causing all kinds of uncontrolled temperature variation in the water supply as well as a phenomenon known as temperature creep. This happens overnight under low or no demand conditions where the domestic water loop could reach as high as 160F and create a scalding hazard for the first, early morning student users. To combat this issue the University maintenance department had to continually rebuild and replace the thermostatic mixers, resulting in huge maintenance expenses.
Heat-Timer Rebuilds the Domestic Hot Water Solution Digitally.
In this domestic hot water system rehabilitation, there were basically two main goals set by the University. The first was to replace the existing thermostatic mixers with newer digital mixing valves that provide the accuracy needed. The second goal was to limit the down time of the installation and have hot water service back to the students as quickly as possible. At the recommendation of Casey, OU decided to replace its unreliable tube bundles with the Heat-Timer® Electronic Tempering Station (ETS)
The Heat-Timer® ETS product introduced in 2020, was a game changer for commercial plumbers in domestic hot water applications. Essentially the ETS encapsulates our industry standard Electronic Tempering Valve (ETV) system which has been a class leading DHW solution for many years with a strong track record in multi-family apartment buildings, hotels, elderly living facilities and college dorm applications. The ETV is a computer tied to our motorized 3-way mixing valve and sensors. Using proven software algorithms to control the mix, our solution delivers an exact, preset hot water temperature to the user, under any and all conditions. The ETV is able to perfectly detect and control the hot water supply temperature to a distribution line.
The ETS assembly is a floor mounted unit that does not require valuable wall space that is difficult to find in most mechanical rooms. The ETS assembly provides the installer the near valve piping configuration, and required fittings such as isolation valves, check valves and Victaulic couplings. The ETS assembly also includes a high-temp limit valve that provides protection against delivery of extreme high temperature domestic hot water to the building in the event of a system failure. The ETV mixing valve actuator, control module and 3 temperatures sensors are included in the ETS assembly and are pre-wired for the installer.
Results of the Domestic Hot Water Retrofit at Oklahoma University
The initial project was for a 12 story dormitory building and the complete removal and installation of the ETS was done in less than a day. Here’s what water temperatures looked like before and after:
The result of having the ETS in place is shown on the computer screen above measuring the mixed water temperature going out to the system. The graph on the left of the screen was the “before”, the huge dip was the system installation, and the flat line is the “after” with the ETS on-line.
“The big take away here is we were able to replace the tube bundles and add the ETS to create an almost completely new domestic hot water system for half the cost of replacing the original package,” notes Casey. This is the first of 2 ETS units sent to OU. Based on the installation time and performance, there is an opportunity for many more to come.
But perhaps Oklahoma University’s Facility Maintenance Manager said it best: “I wouldn’t have believed how simple it was to install and how consistent our temperatures are if I hadn’t seen it for myself.”
You won’t believe it either. Call Heat-Timer® Today for all your questions about our Domestic Hot Water Control solutions.
Original blog posted on https://www.heat-timer.com/oklahoma-sooners-play-ball-with-heat-timer/
The actual phrase “penny wise, and pound foolish” is often mistakenly credited to Benjamin Franklin, but it actually originated with an Oxford Scholar named Robert Burton in his book, “The Anatomy of Melancholy” written in 1621!
Needless to say, in 1621 domestic hot water wasn’t even a thing. It was before the advent of electricity, multi-story distributed hot water systems, and certainly before the advent of modern boilers, computerized boiler controls and mixing valves.
And yet the phrase is nowhere more relevant than when it is applied to DHW installations where mixing valves are sometimes omitted for small overall reductions in material cost or piping complexity in a commercial, domestic hot water setting.
So here’s “penny wise and pound foolish” as applied to your domestic hot water system .
The Purpose of a 3 Way Mixing Valve in DHW
In DHW applications using traditional direct-fired storage tank systems, a mixing valve has always been an important part of the overall system design as shown in the graphic below:
The typical 3-way valve serves several primary purposes:
These numbers are just what is reported of course. The National Academies of Sciences, Engineering, and Medicine estimates that as many as 70,000 people may suffer from the disease each year, according to a report released in August 2019. The disease can cause severe sickness and even death. Individuals with a history of health issues, smoking or who are over 50 are even more at risk. For facilities, the consequences of finding the bacteria can be catastrophic, even if not deadly. The water must be shut off, expensive mitigation strategies can be required, there is almost always negative media coverage often national, and of course, there is the potential for lawsuits or even financial ruin.
How Saving Pennies threatens the whole system.
It turns out that there is a lot of misinformation out there about what does and doesn’t compromise the integrity of a domestic hot water delivery system. Some of this misinformation is even propagated by manufacturers of tankless system who want you to believe that their on-demand systems are safe to run at much lower temperatures, thus saving energy.
The truth is however quite simple and the science behind it is easily available on the websites of Federal regulatory agencies like the CDC, the World Health Organization, and private research companies.
Consider the following commonly used table of Legionella growth.
The disinfection of your hot water is dependent on two primary things: The temperature of the hot water and the time it remains at that temperature. Period. And the only way to manage the proper disinfection of hot water, without risking scalding injuries at the fixture, is through management of water temperatures using a 3 way mixing valve.
A Little More Work, A Lot More Safety
Heat-Timer® recognized a while ago that installers needed a simpler and faster solution to the installation of 3 way mixing valves. That’s why we developed the Electronic Tempering Valve (ETV) and the Electronic Tempering Station or ETS. The ETS provides installers the convenience of a pre-piped and pre-wired assembly of the ETV valve and module. The installers only need to connect the hot and cold water supply, and provide power to the controller to have a completely safe, pre-plumbed solution to domestic hot water safety.
For more information on Heat-Timer’s electronic tempering valve solutions for domestic hot water applications, please contact a Heat-Timer® representative today at: (973) 575 4004.
Original blog posted on https://www.heat-timer.com/domestic-hot-water-solutions/
Heat-Timer® corporate office and manufacturing facility is conveniently located in Fairfield, NJ. Here, Heat-Timer® manufactures its electronic controls, sensors, valves and actuator products using specialized computer controlled equipment and automated testing systems.