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9. Examine the valve assembly for any heavy scoring on the valve shoe. Should the
valve assembly be heavily damaged in any way, i.e. heavy scoring on shoe, then
replace the shoe or the whole assembly.
4.4 Replacement of Indexing Valve
Before replacing the valve assembly, examine the “O” rings on both the inside and outside
of the valve assembly and replace if necessary.
1. By looking down the length of the indexing valve body, align the vertical opening in
the backwash shoe with the dowel pin located on the top circumference of the
indexing valve body. This will ensure that the valve is in the filter position.
2. Lubricate the three “O” seals and insert valve assembly into the inlet chamber. Take
care to align the dowel pin with its recess in the inlet chamber, and not to move the
valve shaft.
3. Replace retaining ring and ensure correct fit into recess.
4. Replace motor, gearbox and control assembly. It may be necessary to first fit the
assembly onto the drive shaft and then rotate the mounting plate to align the four
screw holes. Using a long screwdriver, lightly touch down the four screws such that
the mounting plate is very lightly secured.
5. Reconnect wiring between circuit board and control cover and fit control cover to
housing.
6. Initiate a manual backwash and check that the motor stops at each pod position and
then parks. Repeat and gently tighten the four screws while in backwash mode.
7. Put filter back on-line and check for correct operation.
4.5 Setting up Opto Disc
As previously mentioned, the opto disc controls the position of the indexing valve by
‘reading’ the hole positions on the disc. These positions are used during the backwash
procedure to align the Indexing Valve Shoe to each port. It also provides the signal to the
controls when the indexing valve has reached the home position after a backwash cycle.
The position of the disc is factory set. For on-site adjustments to the disc, please follow the
procedures below.
1. Carry out the routine for removing the Indexing Valve as outlined in Section 4.3.
2. Check the position of the shoe to the valve body as in Section 4.4 to ensure that the
shoe is in the home position (filter position).
3. Once the shoe is in the filter position, align the shaft on the motor/gearbox so that the
opto disc is also on its home position. To accomplish this, place the motor/gearbox
assembly onto the indexing valve shaft to see if the shaft and the four mounting holes
in the mounting plate line up with the holes in the filter. During this procedure be very
careful not to rotate the shaft on the indexing valve or the indexing shoe will mover
from its home position and steps 1 and 2 will need to be repeated.
4. Once the motor/gearbox is fitted onto the Indexing Valve shaft, check alignment of
mounting holes on gearbox assembly to the four holes in the filter. If the holes are
aligned, then the set-up procedure is complete. If misaligned, then proceed to the
next step.
