Thrush MP User Manual

9636-0510

OPERATION & MAINTENANCE INFORMATION

FOR

MODEL GT & GTB IN-LINE CENTRIFUGAL PUMPS

AND MP PUMPS

MODEL GT & GTB

The Th rush In-Line Centrifugal Pump has bee n carefully assembled and factory tested to provide
years of trouble-free service. In order to assure the service intended, the following information is
provided to enable proper installation, op eration and maintenance of the GT / GTB pump.

MODEL MP PUMP

The Thrush MP pump uses standard GTB replacement parts for easy parts replacement. The motor
and bearing assembly have sealed ball bearings and never ha ve to be oiled or grea sed. The motor is
also resilient mounted for reliable quiet operation. The pump comes with the standard Type 21 seal,
stainless steel shaf t and external water slinger for added bearing assemb ly life in case of seal failure.
Because of the universal machining of the bracket assembly, the Thrush Boiler Manifold Pump will
replace most models on the market today.

INSTALLATION

LOCATION

The pumps should be located as close to the liquid source as possible so that the suction line can be
short an d irect. It should be located in a clean, o pen area, where it is easily accessible for inspection,
lubrication and repair. Pumps installed in dark, dirty areas or in cramped locations are often
neglected which can result in premature failure of both the pump and the drive.

Adequate provisions shou ld be made fo r electrical wiring to the pump moto r. A switch and overload
protection should be installed near the pump. The flexible electrical conduit should be used in
connecting motor wiring.

7/09

GT / GTB - Stock and Custom

In-Line Circulator

MOUNTING

PIPING

SUCTION PIPING

DISCHARGE PIPING

Thrush In-Line pumps conserve floor space, simplify piping and can b e serviced without discon­necting piping. They are designed to be installed in the horizontal position. The proper installation of
these pumps is to install them as a part of the piping. The p umps must be free to travel with the
expansion and contraction of the piping. In-line installation eliminates the problems normally
encountered in aligning piping to a base mounted unit.

SUPPORT OF THE GT SERIES PUMPS SHOULD ALWAYS BE CONNECTED TO THE PIPING
RATHER THAN TO THE PU MP CASING

. The line-mounted fea ture eliminates the need for installing
flexible pipe connectors at either the pump suction or d ischarge. Isolating valves should be installed
at both the pump suction and discharge to permit servicing of the pump without draining the entire
system. Make certain the space around the pump is sufficient to give clearance for remo ving the
pump assembly from the casing. Also the space around the pump should be large enough for
general accessibility and ventilation. The same criteria an d form ula for selecting piping supports are
used with the additional consideration that the weight of the pump is concentrated at one point in the
piping.

The piping practices you follow will directly affect the efficiency and power consumption of your pump.
Pay particular attention to the seemingly insignificant details involved in piping for they make the
difference between a good and bad installation. BOTH THE SUCTION A ND THE DISCHARGE
PIPING SHOULD BE INDEPENDENTLY SUPPORTED NEAR THE PUMP. LIBERAL USE OF PIPE
HANGERS AND SU PPORT BLOCKS WILL PREVENT EXCESSIVE STRAI N ON THE PUMP
CASING AND ON THE PIPE JOINTS . Th e suction diameter sho uld be at least the same diameter as
the suction nozzle on the pump and preferably larger. All joints must be tight to maintain prime on the
pump.

Long radius elbows should be used in place of standard elbows whe rever possible, because of their
superior flow characteristics. Elbows installed in any position at the suction nozzle have a tendancy to
distribute th e liquid unevenly in the impeller eye and may cause a red uction in capacity which creates
an undesirable thrust condition or creat noisy operation. Eccentric reducers should be installed
directly at the suction nozzle, with the taper at the bottom to prevent air pockets from forming.
Straight taper reducers should never be used in a horizontal suction line because of the air pocket
that is formed at the leg of the reducer and the pipe.

The discharge piping diame ter should be the same as, or larger than, the discharge nozzle diameter.
The size of the discharge pipe to be u sed is dep endent upon its application.
PROPER P IPING ALIGNMENT IS ESSENTIAL BEFORE CONNECTION IS MADE. PIPING
ALIGNMENT SHOULD NEVER BE ACHIEVED BY FORCE, THIS COUL D PROCUCE STR AIN ON
THE PIPIN G AND THE PUMP CASING. NOTE: Centrifugal pumps should never be started or run
dry.

Operating a pump dry will c ause scoring of the mechanic al seals, resulting in premature

seal failure. To prevent the pump from being run dry, it should be pr imed before starting.

PRIMING THE PUMP

FLOODED SUCTION PRIMING

The pump will not operate satisfactorily until is is primed. All air must be expelled from the suction
piping and pump casing and replaced by the liquid to be pumped. Th ere are several methods of
priming pumps. The one selected will depend on the specific requirements.

This method of priming a pump is relatively simple. The liquid source is locate d above the pump and
all that is necessary to prime the pump is to open the air vent valve or plug in the pum p casing and to
crack the isolating valve in the suction line. The suction line and pump should be filled slowly until a
steady stream of liquid is observed flowing from the air vent. After the pump is operating, it is
recomm ended that the air vent valve or plug be opened again to insure tha t all air has been expelled
from the pump casing.

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 soo n as the pump is up to operating speed, the
discharge isolating valve should be opened to the desired position. The 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 hav e
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 un necessary to disconnect piping or casing t o 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 mot or

3. Rem ove casing bolts conne cting casing (2) and bracket (5) and entire pump assembly can
be withdrawn from casing.

4. Rem ove 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. Rem ove seal seat and O-ring from bracket. Clean sea l 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. Rem ove old casing gasket and clean off any pieces that may have been broken off on the
casing. Put new ga sket 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 m otor wiring. Check motor rotation to insure proper operation.

MOTOR REPLACEMENT

1. Disconnect wiring.

2. Loosen coupling (10) at impeller shaft

3. Loosen moto r crad le clamps.

4. Loosen moto r crad le bolts and slide apart.

5. Rem ove 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.

CARTRIDGE REPLACEMENT

1. Shut off power to motor and disconnect wiring to motor.

2. Close shut off valves on suction and discharge of pump.

3. Loosen coupling on pump shaft.

4. Rem ove mo tor and cradle assembly from bracket. It is not necessary to remove motor f rom
cradle.

5. Rem ove eight screws ho lding bracket to body and remove bracket from pump body.

6. Rem ove impeller nut then remove impeller and key from shaft.

7. Rem ove seal assembly from shaft per seal replacement instruction.

8. Rem ove cartridge bolts that fasten bearing cartridge to bracket, remove cartridge, and
replace with new cartridge bearing assem bly.

9. Re-install seal per instructions, install impe ller, key and tighten imp eller nut.

10. Replace gasket if necessary; bolt bracket to pump body, re-at tach motor and cradle to
bracket.

11. Align and tighten coupling.