Clack WS1 TT Duplex Replacement Valve

The Clack WS1 TT Duplex Replacement Valve, supplied by WrekinWater, is a complete twin-tank control valve assembly that alternates between two resin vessels so one tank is always in service while the other regenerates, giving continuous soft water with no interruption. It's the standard upgrade or like-for-like replacement for households and light commercial sites running a Clack-based duplex softening system that has reached the end of its serviceable life.

Technical specifications

Symptoms that mean you need this part

• The valve fails to alternate correctly between the two tanks, leaving one vessel permanently offline or in service
• Persistent leaks from the valve body, cracked housing, or a body that can no longer be repaired with seal/spacer kits
• The electronic controller has failed, is obsolete, or displays fault codes that a reset or new circuit board won't clear
• Hard water is getting through even after repeated regenerations, seal kit replacements and adjustment

Why it fails / why it matters

A duplex valve is doing twice the mechanical work of a single-tank valve, cycling pistons and seals far more often to keep switching supply between tanks without interruption, so after many years of continuous service the valve body, drive components and electronics reach a point where individual seal or spacer kits stop being a cost-effective fix. Once the plastic body has stress-cracked, the motor or controller has failed, or the valve simply predates currently available service parts, a full replacement valve restores continuous soft water reliably rather than chasing recurring faults.

Why buy this from WrekinWater

WrekinWater has served more than 50,000 customers over 15 years from our base in Bettisfield, Shropshire, and we stock genuine Clack valve assemblies including the WS1 TT duplex range alongside Pentair Fleck, Autotrol and Kinetico equivalents. Rated "Excellent" on Trustpilot and registered as UK Company No. 11000488, we can advise on compatibility before you order and supply the correct replacement valve for your existing twin-tank installation.

How to fit it

1. Have a competent installer or water treatment engineer confirm the replacement valve's connections, thread size and control settings match your existing twin-tank pipework before ordering.
2. Isolate the mains water supply and fully depressurise both resin vessels before disconnecting the old valve.
3. Remove the existing duplex valve from both tank heads, taking note of inlet, outlet, drain and brine line routing.
4. Fit the new Clack WS1 TT valve to both tank heads using new O-rings/seals, ensuring both vessels are correctly connected for alternating operation.
5. Reconnect drain and brine lines, restore the water supply gradually, and check for leaks at every connection.
6. Program the controller with your resin volume, hardness and regeneration settings, then run a full test cycle on each tank before returning the system to service.