Clack WS2 and WS2QC Service Kit (Stack and Pistons) Regenerating

The Clack WS2 and WS2QC Service Kit for the regenerating cycle piston is a genuine stack and piston rebuild kit for the larger commercial-size WS2 and WS2QC control valves, and WrekinWater stocks it for installers and site engineers maintaining Clack-based commercial softeners across the UK. This kit renews the wearing stack seals and piston that drive the regeneration and brine draw stage of the cycle, restoring correct operation without the cost of replacing the entire valve.

Technical specifications

Symptoms that mean you need this part

• The softener no longer draws brine from the tank during regeneration
• Water leaks or weeps from the drain line specifically during the regeneration stage
• The valve stalls, hesitates or fails to advance through the brine draw and rinse stages
• Salt usage drops noticeably or the brine tank stops emptying as expected

Why it fails / why it matters

The stack and piston in the regenerating section of a WS2/WS2QC valve controls the brine draw and slow rinse stages of the cycle, and repeated exposure to concentrated brine solution is particularly hard on rubber seals, causing them to swell, harden or crack faster than in other parts of the valve. Once these seals fail, brine either doesn't draw properly — leaving the resin under-regenerated and the softener producing hard water — or the valve weeps water to drain during the cycle, and a worn piston can also stick and stall the regeneration part-way through.

Why buy this from WrekinWater

WrekinWater has served more than 50,000 customers over 15 years from its base in Bettisfield, Shropshire, and stocks genuine Pentair Fleck, Autotrol, Clack and Kinetico spares including this WS2/WS2QC regenerating service kit, so installers get the correct part for the brine draw stage rather than a mismatched substitute. As UK Company No. 11000488 and rated Excellent on Trustpilot, the team can help confirm which cycle kit your valve needs before you order.

How to fit it

1. Isolate the water supply and relieve system pressure, then place the valve in bypass if fitted
2. Remove the valve's cover screws to access the regenerating stack and piston assembly
3. Withdraw the old piston and stack, noting the order and orientation of seals and spacers as you go
4. Clean the bore thoroughly, checking for salt scale or scoring before fitting new parts
5. Fit the new stack and piston from the kit, lightly lubricating seals with a food-grade silicone lubricant as specified by Clack
6. Reassemble the cover, restore water supply, and run a manual regeneration cycle to confirm brine draw and rinse are working correctly with no leaks to drain