Clack WS1.25 CI Filter time controlled valve, 1.25in V125CIBTZ-08

The Clack WS1.25 CI Filter time controlled valve V125CIBTZ-08, supplied by WrekinWater, is a complete 1.25" cast-iron-bodied control valve that runs backwash filtration on a fixed time-clock schedule, built for higher flow rates than a standard 1" residential valve. It's the correct replacement assembly for larger households, commercial premises or private water supplies running a Clack-based filter that needs the extra flow capacity and durability of the CI (cast iron) body.

Technical specifications

Symptoms that mean you need this part

• The valve body has cracked, is leaking, or shows corrosion that seal kits alone can no longer fix
• The timer motor or electronics have failed and are obsolete or uneconomical to source parts for
• Filtration performance has dropped — poor taste, colour or sediment breakthrough — despite correct backwashing
• The valve won't complete its backwash/rinse cycle reliably, or repeated regeneration faults keep recurring

Why it fails / why it matters

A 1.25" filter valve running higher flow rates day in, day out puts more mechanical stress on the piston, seals and drive components than a standard residential valve, and cast iron bodies — while more durable than plastic — can still suffer from internal wear, corrosion at fittings, or a timer mechanism reaching end of life after years of continuous cycling. Once the valve can no longer hold a reliable timed backwash schedule or the body itself is compromised, filtration performance and consistency suffer, and a full valve replacement is more reliable than repeated partial repairs.

Why buy this from WrekinWater

WrekinWater has supplied water treatment equipment to more than 50,000 customers over 15 years from Bettisfield, Shropshire, and we stock genuine Clack CI valve assemblies alongside Pentair Fleck, Autotrol and Kinetico ranges for commercial and higher-flow applications. Rated "Excellent" on Trustpilot and registered as UK Company No. 11000488, we can help confirm this valve matches your existing tank and pipework before you buy.

How to fit it

1. Arrange for a competent installer or water treatment engineer to confirm the tank thread, flow rate requirement and pipework size match this 1.25" valve before ordering.
2. Isolate the water supply and fully depressurise the filter vessel before removing the old valve.
3. Remove the existing control valve from the tank head, noting the inlet, outlet and drain connections.
4. Fit the new Clack WS1.25 CI valve to the tank head with new O-rings/seals, ensuring the riser tube seats correctly.
5. Reconnect drain pipework and restore the water supply gradually, checking every joint for leaks.
6. Program the time clock for your required backwash schedule and run a full test cycle before returning the filter to service.