Tag: CSU-CW

News headlines about Legionnaires’ disease outbreaks are a stark reminder of a critical public health challenge that often originates within the very water systems of our commercial, institutional, and residential buildings.

Legionnaires’ disease, a severe form of pneumonia, is caused by Legionella bacteria, which thrive in specific conditions found in complex plumbing systems.

When cold water flow is minimal or stopped altogether, disinfectant levels evaporate, and temperatures gradually rise to the Legionella growth range (77–113°F, 25–42°C), leading to bacterial colonization and uneven free chlorine distribution throughout the system.

Understanding how these bacteria flourish in various parts of a building’s water infrastructure and how to prevent their growth proactively is crucial for safeguarding public health and ensuring compliance.

Understanding the Threat of Legionnaires’ Disease

Legionnaires’ disease is a severe lung infection contracted by inhaling small droplets of water (aerosols) contaminated with Legionella bacteria. Various building water systems, including showers and faucets, can generate these aerosols. It’s important to note that Legionnaires’ disease is not spread person-to-person.

Symptoms can range from mild to severe, including cough, shortness of breath, high fever, muscle aches, and headaches. While some individuals recover, Legionnaires’ disease can be fatal, particularly for those with weakened immune systems or chronic lung conditions. The severity and public impact of outbreaks underscore the critical need for effective and proactive prevention strategies.

The Critical Role of Balanced Recirculation

Recirculating cold water eliminates stagnation, which promotes harmful bacteria growth, and provides consistent distribution of residual chlorine throughout domestic cold-water systems:

• Keeps water moving
• Maintains water quality to reduce stagnation
• Ensures residual chlorine is distributed throughout the cold-water system
• Keeps water temperature in branches and risers evenly distributed, minimizing heat gain

How Thermostatic Technology Changes the Game

Implementing effective recirculation, particularly in large and complex plumbing systems, requires precision to ensure adequate flow to all branches without creating significant water waste or manual balancing. This is where self-actuating thermostatic valve technology comes into play.

How the CircuitSolver^® CSU-CW Valve Works

The CircuitSolver^® Union Cold Water valve, using innovative automatic thermal balancing technology, offers a robust solution for optimizing cold water recirculation loops, ensuring optimal conditions for Legionella control.

The CSU-CW valve utilizes the same reliable and precise thermal actuator technology as the original CircuitSolver^®. It addresses critical issues related to Legionella mitigation in cold water recirculation systems by maintaining a stable temperature. It accomplishes this by continuously monitoring the water temperature and modulating flow to maintain a set temperature at the end of each branch or riser.

The valve operates over a 10°F temperature range. For example, a valve specified for a desired return temperature of 60°F will open at 70°F (10°F above the desired return temperature). At 60°F, the valve is in its closed position. A bypass in the design always allows water to flow back to the pump so that the pump is never dead-headed.

The CircuitSolver^® Difference

Simplified Design & Operation

Unlike manual balancing valves that require extensive, often inexact, commissioning and re-balancing, automatic valves like CircuitSolver^® provide continuous, dynamic balancing. This eliminates the need for manual adjustments, saving time and labor while ensuring optimal, ongoing system performance.

_{Enhanced Efficiency}

By intelligently directing flow only where needed, CircuitSolver^® thermostatic balancing valves maximize the effectiveness of the recirculation system, leading to both safety and cost savings.

_{Mitigate Legionella with Thermostatic Technology}

By taking a proactive, comprehensive approach to Legionella control and utilizing advanced technology like CircuitSolver’s automatic thermal balancing valves, you can transform your building’s water system from a potential risk into a safe, reliable, and compliant resource, mitigating Legionella bacteria.

Find more information about our thermostatic balancing valves here.

How Can Legionella Grow in Cold Water Systems?

Stagnant, warm water in a plumbing system increases the risk of Legionella bacteria growth. In cold water systems, adequate flow through high fixture usage and low water temperatures discourage the growth of Legionella and other biofilms. However, in the event flow throughout the system or part of the system is insufficient, standing water can drastically increase the likelihood of bacteria colonization.

When cold water flow is minimal or stopped altogether, as seen during the recent COVID-19 lockdowns that left buildings unoccupied for long periods of time, disinfectant levels evaporate, and temperatures gradually rise in the Legionella growth range, leading to bacteria colonization and uneven free chlorine distribution throughout the system.

Legionella bacteria causes Legionnaires’ disease, a type of pneumonia infecting the lung. People can get sick when they breathe in water droplets or accidentally swallow water containing Legionella.

The CDC says Legionella grows best in a building’s cold water distribution system within a specific temperature range of 77°F-113°F (25°C-45°C). Cold water temperature throughout the system should be maintained at or below 77°F (25°C) to the greatest extent possible to inhibit growth.

To discourage Legionella bacteria growth, cold water systems need to be recirculated. They must be balanced appropriately to establish continuous flow and keep line temperatures below 68°F (20°C), the point at which Legionella can begin to colonize.

The Veterans Health Administration (VHA) aims to prevent the spread of healthcare-associated Legionella disease and scald injury from water systems in VHA buildings where patients, residents, or visitors stay overnight with the VHA Directive 1061(1).

The directive states, “The use of piping system insulation, automatic drain devices, and recirculation to limit the rate and duration of an increase in cold water temperature in combination with appropriate biocide levels can be effective at preventing Legionella growth.”

The Need for Dynamic Balancing

In order to achieve stability, system balancing must be dynamic – continually addressing the ever-changing conditions. Thermostatic balancing valves adjust dynamically, providing the best opportunity for sustainability and Legionella mitigation. Traditional manual balancing valves could provide a solution to cold water balancing, but their static operation inherently does not factor in nor adapt to the realities of everyday system operation & changes, which may render the balancing obsolete over time.

CircuitSolver® Union Cold Water (CSU-CW) Balancing valve will automatically keep cold water moving and maintain water quality, reducing stagnation and the growth of bacteria.

Utilizing our proprietary thermal actuator as the controlling element, the valve should be installed at the end of each branch or riser in a cold water recirculation system. It will modulate open or closed in response to the water temperature to maintain a specified temperature in the line.

The CSU-CW valve features a union with an optional check valve built into the body of the CircuitSolver® to reduce the number of system components installed and minimize potential leak points.

CSU-CW benefits:

• Stainless Steel, which is highly resistant to scaling in high mineral content environments
• High thrust actuator keeps orifice free of debris
• Union with integrated O-ring for a leak-free seal
• Keeps water temperature in branches/risers evenly distributed, minimizing heat gain
• Never fully closes, some water always passing through
• Provides even distribution of residual chlorine levels

These systems have become more prominent in VA hospitals because of the VHA 1061(1) directive; however, any commercial building such as schools, hotels, high-rise, and multi-family apartment buildings can benefit from implementing a cold-water recirculation system to protect the water lines from the risk of bacteria colonization during periods of low flow or non-use.

Watch how it works and see how the CircuitSolver® Union Cold Water thermostatic balancing valve automatically and continuously balances your cold-water recirculation system to discourage Legionella bacteria colonization and reduce stagnation.

Find out more here.