Nova-Tech LMI Series G - SG Metering Pump - Manual (Page 26)

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4. Torque the six diaphragm head bolts to the fol-
lowing inch pounds in a crisscross pattern:
(1) Liquid End Size SG5 and SG6 metallic and
non-metallic head bolts to 90 inch pounds.
(2) Liquid End Size SG7 non-metallic head
bolts to 125 inch pounds.
(3) Liquid End Size SG7 metallic head bolts to
250 inch pounds.
4.4.3 Replacing Oil Seal
BEFORE BEGINNING OIL SEAL
REPLACEMENT, MAKE SURE THAT
ALL SHUT-OFF VALVES ARE CLOSED
AND ALL PRESSURE IS BLED FROM
THE LIQUID END. MAKE SURE POWER
TO PUMP IS TURNED OFF AND CAN-
NOT BE ACTIVATED.
When replacing the oil seal, the diaphragm assem-
bly must be removed first. For ease of service, it is
recommended that the oil seal be replaced in con-
junction with the diaphragm assembly. Therefore,
the instructions below include the “Diaphragm
Replacement” instructions, and can be used for
both oil seal replacement and diaphragm replace-
ment.
Disassembly (Refer to Figure 6 through 13).
1. Drain oil from the pump by unscrewing drain
plug and O-ring, located underneath capacity
adjustment knob (330).
2. Set the capacity adjusting knob (330) to 100%.
3. Disconnect the suction and discharge piping.
4. Unscrew the six diaphragm head bolts.
5. Remove the diaphragm head assembly from
the pump body.
6. Turn the motor fan by hand (remove the
shroud if necessary) until the end of the diaphragm
assembly (240) is fully forward, and unscrew the
diaphragm from the connecting rod (60), using a
30mm hex socket on diaphragm cap (240).
7. Remove the diaphragm support ring (230).
8. Remove the retaining ring (220) from the con-
necting rod.
9. Slide the small oil seal clamp (210) off the
connecting rod.
10. Remove the large oil seal clamp (80) by
unscrewing the four slotted screws (90).
11. Pull the oil seal (70) off of the connecting rod.
Reassembly (Refer to Figure 6 through 13).
1. Install a new oil seal (70) onto the connecting
rod.
2. Slide small oil seal clamp (210) onto the end of
the connecting rod and secure in place with the
retaining ring (220). A drive socket large enough to
fit over the end of the connecting rod should be
used to push the retaining ring until it snaps into
place in the retaining ring groove in the connecting
rod.
3. Secure the large oil seal clamp (80) over the oil
seal with the four slotted screws (90).
4. Place the diaphragm support ring (230) into
position making sure beveled side (for diaphragm
support) is facing up (refer to Figure 6 through 13).
For SG7 liquid ends, the support ring (230) has
stepped diameters. Make sure that the larger
diameter is installed into the metal adapter ring
(225 Figure 12 and 13).
5. With the stroke adjusting knob at 100% and
the diaphragm fully forward as in steps 2 and 6 of
disassembly instructions, screw the diaphragm
assembly into the connecting rod until it reaches its
natural mechanical stop.
6. Turn the motor fan by hand until the diaphragm
rests properly on the diaphragm support ring (230).
Reinstall the motor shroud if previously removed.
With the stroke adjusting knob at 100% and the
diaphragm fully forward as in steps 2 and 6 of dis-
assembly instructions, screw the diaphragm
assembly into the connecting rod until it reaches its
natural mechanical stop.