Skip to content
English
Contact us
  • There are no suggestions because the search field is empty.

How to Replace a Stack Assembly and Piston on a Clack WS1 Valve

This guide walks through how to replace the stack assembly and piston on a Clack WS1 valve. This procedure is commonly used during service or maintenance on Flow Tech systems. 


 

Before You Start

Make sure you have:

  • Replacement stack assembly and piston

  • Clack wrench or flat screwdriver

  • Access to the system controls

Step 1. Depressurize the System

  1. Put the unit into bypass by turning the bypass handles so they face each other

  2. Press and hold the regen button until the valve moves into the backwash position

  3. This releases pressure from the system

Step 2. Remove the Faceplate and Control Head

  1. Remove the faceplate by pulling outward on the two side tabs

  2. Disconnect the power wire and set it aside

  3. Lift up on the two top tabs of the control plate

  4. Tilt the plate outward and lift it up

  5. Fold the control head back carefully so wires remain connected and undamaged

Step 3. Remove the Piston and Stack Assembly

  1. Locate the black retaining wheel

  2. Use the Clack wrench to loosen it

    • A screwdriver can be used if a wrench is not available

  3. Unscrew the wheel fully and remove the piston and stack assembly

  4. Pull the stack assembly straight out and set it aside

Step 4. Replace the Piston

  1. Rotate the white gear to move the piston upward

  2. Locate the slot where the piston connects

  3. Remove the old piston

  4. Insert the new piston into the slot

  5. The valve will self align once powered on

Step 5. Reinstall Components

  1. Insert the new stack assembly

  2. Reinstall the black retaining wheel by hand

  3. Use the wrench to tighten until snug

    • Do not overtighten or force

  4. Lower the control head back into position

  5. Make sure wires are not pinched

  6. Snap the control plate back into place

  7. Reconnect the power wire

Step 6. Pressurize and Test

  1. Slowly crack open the inlet valve

  2. Check carefully for leaks

  3. Fully open the valve once pressurized

  4. Return the system to service

  5. Reset the clock on the control head

  6. Run a full regeneration cycle if the system was powered off for an extended time

Final Check

Once regeneration is complete, the valve will return to filter mode and the system is ready for normal operation.

Need Help

If you have questions or need assistance, contact Plumber’s Choice Water support or your Flow Tech representative.