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Thermostatic Balancing Valve Helps Defend Against Legionella

August 18, 2020 Viega
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As buildings reopen during the COVID-19 pandemic, there is renewed concern about the quality of the water in long-dormant plumbing systems, particularly in regards to the legionella bacteria, the cause of Legionnaire’s disease.

To combat this, a number of plumbing regulatory and professional organizations have endorsed procedures for the safe reopening of buildings. Of course, legionella concerns don’t vanish once buildings are occupied again. Balancing hot water recirculation systems to prevent the growth of legionella is a challenge year-round.

It doesn’t help that plumbing codes (UPC, IPC and IECC) and standards (ASHRAE 90.1, ASHRAE 188) aren’t in complete alignment on best practices. But all systems face the same reality: the legionella bacteria grow best in water that is 95°F to 115°F (35°C to 46°C).

Keeping hot water out of that temperature growth zone while still preventing scalding and conserving energy requires a well-designed and well-balanced system with the correct use of balancing valves.  

There are three types of balancing valves: manual (pressure dependent), automatic (pressure independent) and thermal (thermostatic). While the basic manual valve remains the most popular, more engineers and contractors are switching to thermal valves because they do a better job of balancing hot water systems while providing greater control and flexibility.

Viega’s new ProPress Automatic Recirculation Balancing Valve is a cutting-edge example of the technology. It keeps hot water recirculation systems balanced by adjusting flow with changes in temperature. Among its features are:

  • Unlike with manual valves, temperature can be set once and be maintained automatically. Settings can be changed easily, if needed.
  • Can be installed on risers or branches
  • Remote monitoring with temperature sensor
  • Optional thermometer provides visual indication of valve setting
  • Threaded ends allow it to be used with Viega ProPress or Viega PureFlow for easy integration with copper or PEX
  • Includes bypass for thermal disinfection

When paired with other elements of good system design, like Viega double drop elbow fittings to reduce stagnation and eliminate dead legs, the Automatic Recirculation Balancing Valve improves circulation and reduces the likelihood of legionella contamination.

For more information about the Automatic Recirculation Balancing Valve, click here.

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