3M CWS Series, Installation And Operating Instructions Manual

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5-2
SECTION 5: CONTROL VALVE SERVICE INSTRUCTIONS
Drive Assembly:
Remove the valve cover to access the drive assembly.
IMPORTANT NOTE: Disconnect the power source plug (black wire) from the PC board prior to disconnecting the motor or water meter plugs from the PC board. The
power source plug connects to the four-pin jack. The motor plug connects to the two-pin jack on the left-hand side of the PC board. The water meter plug (grey
wire) connects to the three-pin jack on the far right-hand side of the PC board.
The PC board can be removed separately from the drive bracket but it is not recommended. Do not attempt to remove the display panel from the PC board. Handle
the board by the edges. To remove the PC board from the drive bracket, unplug the power, water meter and motor plugs from the PC board. Lift the middle latch
along the top of the drive bracket while pulling outward on the top of the PC board. The drive bracket has two plastic pins that fi t into the holes on the lower edges
of the PC board. Once the PC board is tilted about 45° from the drive bracket it can be lifted off of these pins. To reinstall the PC board, position the lower edge of
the PC board so that the holes in the PC board line up with the plastic pins. Push the top of the PC board towards the valve until it snaps under the middle latch,
weave the power and water meter wires into the holders and reconnect the motor, water meter and power plugs.
The drive bracket must be removed to access the drive cap assembly and pistons or the drive cap gear cover. It is not necessary to remove the PC board from the
drive bracket to remove the drive bracket. To remove the drive bracket, start by removing the plugs for the power source and the water meter. Unweave the wires
from the side holders. Two tabs on the top of the drive back plate hold the drive bracket in place. Simultaneously lift the two tabs and gently ease the top of the
drive bracket forward. The lower edge of the drive bracket has two notches that rest on the back plate. Lift up and outward on the drive bracket to disengage the
notches.
To reassemble, seat the bottom of the drive bracket so the notches are engaged at the bottom of the drive back plate. Push the top of the drive bracket toward the
two latches. The drive bracket may have to be lifted slightly to let the threaded piston rod pass through the hole in the drive bracket. Maintain a slight engaging
force on top of the drive bracket while defl ecting the bracket slightly to the left by pressing on the side of the upper right corner. This helps the drive gears mesh
with the drive cap assembly. The drive bracket is properly seated when it snaps under the latches on the drive back plate. If resistance is felt before latching, then
notches are not fully engaged, the piston rod is not in the hole, the wires are jammed between the drive bracket and drive back plate, or the gear is not engaging
the drive cap assembly. To inspect the drive gears, the drive gear cover needs to be removed. Before trying to remove the gear cover, the drive bracket must be
removed from the drive back plate. (Refer to the proceeding instructions regarding removing the drive bracket from the drive back plate. The drive gear cover can
be removed from the drive bracket without removing the motor or the PC board.) The drive gear cover is held in place on the drive bracket by three clips. The largest
of the three clips is always orientated to the bottom of the drive bracket. With the PC board facing up, push in and down on the large clip on the drive gear cover.
Handle the cover and the gears carefully so that the gears do not fall off of the pegs in the cover.
Replace broken or damaged drive gears. Do not lubricate any of the gears. Avoid getting any foreign matter on the refl ective coating because dirt or oils may
interfere with pulse counting.
The drive gear cover only fi ts on one way, with the large clip orientated towards the bottom. If all three clips are outside of the gear shroud on the drive bracket
and the drive gear cover slips easily into place.
The drive bracket does not need to be removed from the drive plate if the motor needs to be removed. To remove the motor, disconnect the power and motor plugs
from the jacks on the PC board. Move the spring clip loop to the right and hold. Rotate the motor at least a 1/4 turn in either direction so the wires are vertical
(up & down) before gently pulling on the wire connectors to remove the motor. Pulling directly on the wires without rotating the motor may break the wires off the
motor.
Replace the motor if necessary. Do not lubricate the motor or the gears. To reinstall the motor, move the spring clip loop to the right and hold. Gently turn the motor
while inserting so that the gear on the motor meshes with the gears under the drive gear cover. Release the spring clip loop and continue to rotate the motor until
the wires are horizontal and the motor housing engages the small plastic bulge inside the drive bracket motor retainer. Reconnect the motor plug to the two-pronged
jack on the lower left hand side of the PC board. If the motor will not easily engage with the drive gears when reinstalling, lift and slightly rotate the motor before
reinserting. Reconnect the power.
Replace the valve cover. 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. The display should fl ash all wording, then fl ash the software version (e.g.
181) and then reset the valve to the service position.
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 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” fl at 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 2” or the piston cav-
ity. See Figure 7 on page 5-3. The notches are visible through the holes. Lever the screwdriver so the drive cap assembly turns to the left. 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 fi eld. The only replaceable part on the drive cap assembly is the o-ring. Attached to the drive cap assembly is the
main piston and a regenerant piston.
The regenerant piston (the small diameter one behind the main piston) is removed form the main piston by pressing sideways and unsnapping if from its latch.
Chemically clean in dilute sodium 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 bisulfi te or vinegar, or replace the main piston.