CircuitSolver Union Cold Water (CSU-CW)

csu cw product page image - CircuitSolver Union Cold WaterThe CircuitSolver® Union Cold Water thermostatic balancing valve automatically and continuously balances a cold water recirculation system to discourage Legionella bacteria colonization, reduce stagnation, and ensure “residual chlorine” is distributed throughout the system.

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 to be installed and minimize potential leak points.

The valve features an integrated O-ring and is factory assembled for a leak-free seal.

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How It Works:

The CircuitSolver® Union Cold Water valve is installed at the end of each branch or riser in a domestic cold water system (DCWS) to automatically and continuously monitor the water temperature. Utilizing our proprietary thermal actuator as the controlling element, the valve will modulate open or closed in response to changing temperatures to maintain a specified temperature in the line.

The valve will be in its closed* position when the water temperature in the supply branch is under the valve’s set-point and only opens to establish flow when it rises above the set-point. This automatic response to temperature allows the balancing valve to adjust dynamically to the varied usage rates in a DCWS throughout the day.

*Note: The valve will never fully close, allowing a small flow bypass to the return to avoid dead-heading the recirculation pump. The limited flow to your return line will reduce system wear, electricity, and water usage and improve overall system operation.

Valve Components:

The CircuitSolver Union Cold Water valve comprises 100% stainless-steel components, a high-quality O-ring, and an optional check valve.

CSU LineDrawing callouts 1024x596 - CircuitSolver Union Cold Water
1 Valve Body w/ Union Threads 300 series stainless steel
2 Union Nut 300 series stainless steel
3 Female Threaded Inset 300 series stainless steel
4 Plug 300 series stainless steel
5 Operating Spring 300 series stainless steel
6 Thermal Actuator 300 series stainless steel
7 O-Ring Buna-N
8 Check Valve (Optional) Glass Filled Noryl

Typical Applications:

The CircuitSolver® Union Cold Water thermostatic balancing valve can be used in any building with a domestic cold water recirculation system to keep the water temperature in branches or risers evenly distributed, which minimizes heat gain and reduces the risk of Legionella and other bacterial growth.

These systems have become more prominent in VA hospitals because of the VHA 1061 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.



  • All stainless steel – corrosion resistant construction
  • High thrust actuator keeps orifice free of debris
  • Union with integrated O-ring for a leak-free seal
  • Optional check valve built into the body
  • Never fully closes, some water always passing through
  • Long service life and 3-year warranty



  • NSF/ANSI/CAN 61 and 372 Certified
  • Lead Free
  • Fully compliant with Section 1417(d) of SDWA, the Safe Drinking Water Act
  • Supports efforts toward LEED Certification
  • Complies with the Buy American Act



  • Sizes: 1/2”, 3/4″ & 1”
  • Max. Working Pressure: 200 PSIG/14 BAR
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