When it’s time to reopen the doors of our country’s commercial buildings, schools, hotels and the like, ensuring safe and sanitary plumbing water will be crucial. Plumbing systems have at minimum been underutilized or at worst-case idle, allowing dangerous levels of potentially harmful bacteria like Legionella to proliferate.

Professionals who are responsible for maintaining our potable water systems know that “old” or stagnant water has lost its ability to control bacteria and should be flushed before use. However, important considerations can be overlooked: During the flushing process are all taps and fixtures open? How long will flushing take? Will all the water in the building then be safe and ready to use?

For the cold “potable” water in the building, a thorough flush should suffice to remove any build-up of bacteria. The length of flush time will depend on the size of the building and the volume of water in the piping system. For the domestic hot water section of the system, however, stagnant water may remain in the recirculation return piping, which is not always replaced by the system flush.

If a building is using a digital mixing valve to control the DHW supply temperature, that valve can provide the solution to disinfecting the recirculation system. Most digital mixing valves have the capability to deliver a thermal shock through this part of the system, elevating the recirculating water to 150 or 160 degrees Fahrenheit for a specific and measured period of time, thereby killing harmful bacteria and restoring the water to a usable and safe condition.

The CaleffiLEGIOMIX 6000 Series digital mixing valve not only delivers highly accurate mixed water temperature 24/7, it also has industry-unique, calendar-based automatic thermal disinfection programs which can be enabled to control Legionella bacteria. In a properly designed system, this process is fully automatic, safe and effective. The LEGIOMIX has data logging capabilities and can connect to a building automation system for remote monitoring and access.

Reopening after the COVID-19 lockdown will necessitate a transitional period that requires special consideration in order to return to clean and safe potable water. The Caleffi LEGIOMIX has been performing thermal disinfection globally for over 20 years. It is the only digital mixing valve in North America that can execute automatic thermal disinfection by a calendar schedule or on-demand at the touch of a button.

Combined with scald-protection valves like SinkMixer and thermal balancing valves such as the ThermoSetter, Caleffiis proud to offer a total thermal solution for control of safe and sanitary domestic hot water, a unique position in the marketplace. The complete system of thermal control is part of Caleffi’s continuing commitment to excellence in technical innovation.