STA-RITE DYNA-PRO MPRA Series Owner's Manual page 13

Before removing trap cover:
1. STOP PUMP before proceeding.
2. CLOSE GATE VALVES in suction and discharge air.
3. RELEASE ALL PRESSURE from pump and piping
system.
To avoid dangerous or fatal electrical shock
hazard, turn OFF power to motor before working
on pump or motor.
Aside from lubricating trap cover O-Ring, no lubrication
or regular maintenance is needed beyond reasonable
care and periodic cleaning of strainer basket. If shaft
seal is worn or damaged, repair as follows:
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.
Hazardous voltage.
Can shock, burn,
or cause death.
Disconnect power
before working
on pump or motor.
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
(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 8.
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