Watts W100T Twin Alternating Series - Manual (Page 38)

38 W100T Twin Alternating Series Softeners
Drive Cap Assembly, Main Piston and Regenerant Piston
The drive assembly must be removed to access the drive cap assembly. The drive cap assembly must be removed to access the piston(s). The
drive cap assembly is threaded into the control valve body and seals with an o-ring. To remove the drive cap assembly use the special plastic
wrench or insert a ¼” to ½” flat blade screwdriver into one of the slots around the top 2” of the drive cap assembly so it engages the notches
molded into the drive back plate around the top 2” of the piston cavity. The notches are visible through the holes. Lever the screwdriver so the
drive cap assembly turns counter clockwise. Once loosened unscrew the drive cap assembly by hand and pull straight out.
The drive cap assembly contains the drive cap, the main drive gear, drive cap spline, piston rod and various other parts that should not be
dissembled in the field. The only replaceable part on the drive cap assembly is the o-ring. Attached to the drive cap assembly is the main
piston (downflow or upflow) and if a regenerant is used, a regenerant piston. Upflow is not applicable to EA, EE or EI control valves.
The regenerant piston (the small diameter one behind the main piston) is removed from the main piston by pressing sideways and unsnapping
it from its latch. Chemically clean in dilute sodium bisulfite or vinegar, or replace the regenerant piston if needed. To remove the main piston
fully extend the piston rod and then unsnap the main piston from its latch by pressing on the side with the number. Chemically clean in dilute
sodium bisulfite or vinegar, or replace the main piston.
Reattach the main piston to the drive cap assembly. Reattach the regenerant piston (if needed) to the main piston. Reinsert the drive cap
assembly and piston into the spacer stack assembly and hand tighten the drive cap assembly. Continue to tighten the drive cap assembly
using a screwdriver as a ratchet until the black o-ring on the spacer stack assembly is no longer visible through the drain port. Excessive force
can break the notches molded into the drive back plate. Make certain that the main drive gear still turns freely. The exact position of the piston
is not important as long as the main drive gear turns freely.
Reattach the drive assembly to the control valve and connect all plugs. After completing any valve maintenance involving the drive assembly
or the drive cap assembly and pistons unplug power source jack from the printed circuit board (black wire) and plug back in or press and hold
NEXT and REGEN buttons for 3 seconds. This resets the electronics and establishes the service piston position. The display should flash all
wording, then flash the software version and then reset the valve to the service position.