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The Challenge:

One of the buildings on a large Ohio university campus was experiencing a great deal of ‘hammering’ and the excessive noise was disrupting the learning environment.  Students and staff were also uncomfortable with the excessively hot building temperatures.

The facilities staff identified that the problem stemmed from their domestic hot water heat exchanger and steam-to-hot-water converter heating loops.  Apparently, the heating loop temperatures were exceeding the 180° set point causing the heat exchangers to water log on the steam side and hammer.  As a result, the traps on the heat exchangers became damaged and were blowing live steam into the condensate return line, and valves were leaking at the stems. 

The domestic water heaters were experiencing similar issues due to the constant swings of the instantaneous heater packages. 

In an effort to alleviate these temperature and noise issues, the university reset the set point temperature to 112°.  However, by reducing the domestic hot water set point to 112°, the temperature was not “killing the bugs” that could potentially cause Legionella. 

The university contacted Industrial Controls for options and a much needed technical solution.


The Solution:

After surveying the environment and reviewing the issues, Industrial Controls proposed a new, fully skidded and integrated heat exchange package.  This UL approved package included a new heat exchanger (the current one was damaged) complete with stainless steel tubes, a valve acting as a reducing and a control valve, a fully packaged condensate return system (closed loop and steam powered), and a HC900 Honeywell control package.

This system eliminated the water hammer by utilizing the closed loop pressure powered pump package ensuring complete condensate drainage while holding the building temperature set point stable by controlling the valve via the integral HC900 control package. The HC900 control package also gave the university monitoring and alarm capabilities for steam pressure, building loop pressure, temperature, condensate outlet temperature and flows.

Since a closed loop system was utilized, the requirement for flash lines through the roof was eliminated, and a contractor was required only to rig in the system, hook up the steam, tie in the condensate and start up the controls. 

This same package design can also be supplied as an instantaneous domestic hot water heating system.  The “skid” would include a mixing station for distribution and also allow for proper sanitizing of the potable water (a set point of 140° is required and then a blend station is used to get to 112°).

By incorporating the valve, heat exchanger, condensate recovery and controls, the university had a single point of contact, Industrial Control, for the performance of the package. 

This system is now a standard at the university.

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