STA-RITE DYNA-WAVE MPRA Series, Owner'S Manual

Page: 11 / 28

9
Pump Dissasembly/Removing Old Seal
Disconnect power to pump motor.
Be sure valves on suction and return piping are
closed before starting work.
Release all pressure by opening all vents before
starting work.
1. Drain pump by removing drain plugs on bottom of
pump body and trap body.
2. Be sure there is no pressure in trap body; remove
cover (unscrew by turning counterclockwise).
3. Remove 6 nuts, lockwashers and flat washers holding
seal plate to pump body. Pull seal plate and motor
away from pump body. (You may have to
CAREFULLY use a screwdriver to separate body
from seal plate.)
4. Remove seven screws and washers holding diffuser
to seal plate. Remove diffuser.
5. Remove motor canopy. Being careful not to touch
capacitor terminals, loosen capacitor clamp and
move capacitor to one side.
6. Hold shaft with 7/16" open-end wrench on motor
shaft flats.
7. Unscrew impeller from shaft (turn counterclockwise
when facing it).
NOTICE: On 2 HP model, remove impeller
screw (left hand thread - turn clockwise) and
gasket before removing impeller. Inspect gasket
for damage, cracks, etc. Replace if damaged.
8. Remove four screws holding seal plate to motor.
9. Place seal plate face down on flat surface and tap
out ceramic seat (Figure 6).
10. Remove slinger from motor shaft and inspect for
damage or abrasion.
11. Clean seal cavity in seal plate and clean motor
shaft.
Pump Reassembly/Installing New Seal
1. Ceramic seat must be clean and free of dirt, grease,
dust, etc. Wet outer edge with small amount of liquid
detergent; press ceramic seat into seal plate cavity
firmly and squarely with finger pressure (see Figure
7) .
2. If ceramic seat will not locate properly, remove it,
place face up on bench and reclean cavity.
Ceramic seat should now locate.
3. If seat still will not locate properly, place a
cardboard washer over the polished face and use a
piece of 3/4" (19mm) standard pipe for pressing
purposes.
NOTICE: Be sure not to scratch or mar polished
surface or seal will leak.
4. Replace slinger on end of motor shaft so that
impeller sleeve will push it into position. If slinger
shows signs of wear or damage, replace it.
5. Remount seal plate on motor. Tighten bolts to 60-
80 inch-lbs. (69-92 kg/cm) torque.
6. Apply a small amount of liquid detergent to inside
diameter of rotating half of seal.
7. Slide rotating seal member, polished carbon face
out, over impeller sleeve until rubber drive ring hits
back of impeller.
NOTICE: Be sure not to nick or scratch polished
seal face; seal will leak if face is damaged.
8. Screw impeller onto shaft (clockwise); this will
automatically locate seal in seal plate. NOTICE: On
2 and 2-1/2 HP models; install impeller gasket
and lock screw (left-hand thread - turn
counterclockwise). Torque lock screw to 50-55
inch-lbs. (57.6-63 kg/cm).
9. Mount diffuser on seal plate; tighten screws to 10-
14 inch-lbs. (11.2-16.1 kg/cm) torque.
10. Assemble motor and seal plate to pump body with
nuts, flat washers and lock washers. Torque nuts to
120-130 in-lbs. (138-150 kg/cm).
11. Prime pump according to instructions on Page 7.
Figure 6
Mechanical seal
ceramic seat
Polished
surface
Rubber
surface
Figure 7