Thrush MP - Manual (Page 3)

STARTING THE PUMP
LUBRICATION
The discharge isolating valve should be partially closed when the pump is started in order to avoid
possible water hammer and initial power draw. As soon as the pump is up to operating speed, the
discharge isolating valve should be opened to the desired position. T he motor should turn clockwise
when viewed from the motor end and counter-clockwise when viewed from the casing end.
The bracket is permanently lubricated and will never need oil. The standard motors have
sleeve bearings and need to be oiled every 3 months with SAE#20 non-detergent oil. If the
option for a ball bearing motor was selected, the motor is permanently lubricated.
MAINTENANCE AND SERVICE
SEAL REPLACEMENT
1. It is unnecessary to disconnect piping or casing to service GT Series or the MP pumps. All
service and maintenance can be performed by removing pump assembly from casing.
2. Disconnect wiring to the motor
3. Remove casing bolts connecting casing (2) and bracket (5) and entire pump assembly can
be withdrawn from casing.
4. Remove impeller acorn nut by turning it counter-clockwise. Pull off the impeller by wedging
around its periphery and slip out the impeller key from its shaft groove.
5. Slide spring-loaded carbon rotating face off impeller shaft
6. Remove seal seat and O-ring from bracket. Clean seal cavity if required.
7. Press new seal seat into seal seat cavity.
8. Install new rotating seal assembly.
9. Insert key into shaft keyway.
10. Install impeller on shaft and tighten acorn nut securely.
11. Remove old casing gasket and clean off any pieces that may have been broken off on the
casing. Put new gasket on pump casing.
12. Lower pump assembly into casing. Use caution to properly align impeller into casing so that it will not be damaged. Tighten cap screws evenly.
13. Re-connect motor wiring. Check motor rotation to insure proper operation.
MOTOR REPLACEMENT
1. Disconnect wiring.
2. Loosen coupling (10) at impeller shaft
3. Loosen motor cradle clamps.
4. Loosen motor cradle bolts and slide apart.
5. Remove coupling and place on new motor shaft.
6. Place new motor in cradle with oil cups up and slide into position.
7. Re-install motor cradle clamps.
8. Tighten cradle bolts.
9. If spring type coupling, stretch coupling 1/8" and secure to pump shaft.
10. If flange and sleeve type coupling, fit flexible sleeve into coupling flanges and tighten to shaft.