Hellenbrand H-150 Series Owner's Manual page 36

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 thread-
ed 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 1/4" to 1/2" flat blade screwdriver into
one of the slots around the top 2" of the drive cap assem-
bly so it engages the notches molded into the drive back
plate around the top 2" of the piston cavity. See Figure
29. The notches are visible through the holes. Lever the
screwdriver so the drive cap assembly turns counter clock-
wise. 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, 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 and
if a regenerant is used, a regenerant piston.
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 this in dilute sodium bisulfite or vinegar, or replace
the regenerant piston if needed. To remove the main
downflow or upflow 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 this in dilute
sodium bisulfite or vinegar, or replace the main piston.
Reattach the main piston to the drive cap assembly. Reat-
tach the regenerant piston (if needed) to the main piston.
Do not lubricate the piston rod, main piston or regener-
ant piston. Lubricant will adversely affect the clear lip
seals. 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 con-
nect all plugs. After completing any valve maintenance,
press and hold NEXT and REGEN buttons for 3 seconds
or unplug power source jack (black wire) and plug back
in. This resets the electronics and establishes the service
piston position. This display should flash all wording, then
flash the software version and then reset the valve to the
service position.
36
Figure 29
Spacer Stack Assembly
To access the spacer stack assembly remove the drive as-
sembly, drive cap assembly and piston. The spacer stack
assembly can be removed easily without tools by using
thumb and forefinger. Inspect the black o-rings and clear
lip seals for wear or damage. Replace the entire stack if
necessary. Do not disassemble the stack.
The spacer stack assembly may be chemically cleaned
(dilute sodium bisulfite or vinegar) or wiped with a soft
cloth.
The spacer stack assembly can be pushed in to the
control valve body bore by hand. Since the spacer stack
assembly can be compressed it is easier to use a blunt
object (5/8" to 1-1/8" in diameter) to push the center of
the assembly into the control valve body. The assembly
is properly seated when at least four threads are exposed
(approximately 5/8"). Do not force the spacer stack as-
sembly in. The control valve body bore interior can be
lubricated with silicone to allow for easy insertion of the
entire stack. Do not use silicone or any other type of lubri-
cant on the clear lip seals or the piston.