Autotrol Flapper valves 255 p/n 1000250, 255 Valve Disc Set

The 1000250 is the valve disc, or flapper, set fitted inside the piston and spacer stack of the Autotrol 255 control valve. These small discs open and close specific ports as the valve steps through backwash, brine draw, rinse and service, directing water exactly where it needs to go at each stage of regeneration. After years of constant flexing and exposure to mineral scale, the discs harden and split, or their retaining springs weaken, so they stop sealing fully and water finds a path it shouldn't. WrekinWater stocks this genuine-spec disc set to renew the piston internals on the 255 valve.

Technical specifications

Symptoms that mean you need this part

• Water continues to run to drain in normal service position after a regeneration has completed
• Hardness leaks through the softened water even straight after a fresh regeneration, suggesting water is bypassing the resin bed
• You can hear or see water flowing to drain outside of the scheduled regeneration cycle
• The valve has been in continuous service for several years without the internal discs ever being renewed

Why it fails / why it matters

The 255 valve's regeneration sequence depends on the flapper discs in the piston and spacer stack opening and closing the correct ports at each stage, sealed by their retaining springs. Years of mineral scale exposure and constant flexing eventually harden or split the rubber discs, or weaken the springs so the discs no longer seat fully, leaving a permanent leak path to drain or letting water bypass the resin bed even in normal service. Renewing the discs and springs as a set restores correct sealing at every stage of the cycle.

Why buy this from WrekinWater

WrekinWater has supplied Autotrol and Pentair valve components to installers and DIY customers for over 15 years from its Bettisfield, Shropshire base, and stocks the full range of Pentair Fleck, Autotrol, Clack and Kinetico parts so you can renew wear parts rather than replace the whole valve. The business is rated Excellent on Trustpilot and has served more than 50,000 customers who value getting the softener working correctly again without unnecessary water running to drain.

How to fit it

1. Isolate the softener at the bypass valve and relieve pressure before opening the control valve
2. Remove the control valve end cap or piston retaining clip following the 255 valve's service instructions
3. Withdraw the piston and spacer stack and identify which flapper discs are worn, split or hardened
4. Fit the new 1000250 discs and springs to each spacer in the same orientation as the originals
5. Reassemble the piston and spacer stack, checking each disc moves freely and seats correctly
6. Refit the end cap, restore the mains supply, and run a manual regeneration to confirm no water runs to drain in service