CircuitSolver Union Assembly with Strainer (CSUAS)

CSUAS Blue Background 500x200 - CSUAS CircuitSolver® thermostatic balancing valves automatically balance a domestic hot water system (DHWS) in a fraction of the time required by traditional manual balancing methods.

The CircuitSolver® Union Assembly with Strainer features a union with an optional check valve built into the body of the CircuitSolver®, particulate strainer, and isolation ball valves on either side 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 Assembly with Strainer (CSUAS) balancing valve is installed at the end of each branch in a domestic hot water system (DHWS), downstream of the last fixture, to monitor the water temperature using our exclusive Thermoloid® blend wax actuator technology.

The valve will automatically modulate open or close in response to the changing water temperature to maintain a specified temperature at the end of each branch. This continuous response to temperature variation enables each hot water branch to quickly and consistently direct hot water flow to where it is needed – No manual balancing is required.

The CSUAS 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 Assembly valve with strainer is comprised of a stainless-steel valve, a high-quality O-ring, two isolation ball valves, an integrated strainer, and an optional check valve.

For typical specifications and installation/maintenance instructions, visit the Typical Specs + IMI Steps page.
CSUAS LD 1.27.22 1024x325 - CSUAS

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
9 Ball Valve, ½” MxF Brass Lead-Free
10 Strainer Brass Lead-Free

Typical Applications:

The CircuitSolver® Union Assembly with Strainer is often specified for new domestic hot water systems that may have particulates inside of the system due to construction or in water systems with a history of particulate/dirt issues.

To see CircuitSolver® installations in your area, visit our installations page.



  • 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
  • 2 M/F ball valves assembled and leak tested
  • Integrated 20 mesh strainer
  • Never fully closes, some water always passing through
  • Long service life and 3-year warranty


  • NSF/ANSI/CAN 61 & 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”
  • Fixed Temperatures:
    • 100°F (37.7°C)
    • 105°F (40.5°C)
    • 110°F (43.3°C)
    • 115°F (46.1°C)
    • 120°F (48.8°C)
    • 125°F (51.6°C)
    • 130°F (54.4°C)
    • 135°F (57.2°C)
    • 140°F (60.0°C)
  • Max Working Pressure: 200 PSIG/14 BAR
  • Max Working Temperature: 250°F/121°C
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