Thrush GTU - Manual (Page 4)

Seal Replacement
1. Close suction and discharge valves.
2. Break electrical connections to prevent drive unit from being energized during disassembly.
3. Remove 4 bolts from support bracket (38) and 8 bolts (30) from bracket (15) and pull motor
and bracket assembly from casing (28). Remove casing gasket (27).
4. Remove impeller acorn nut (3). Slide impeller (37) and impeller key (14) from the shaft.
5. In replacing seal kit assembly (21 & 22), slide rotary seal assembly (22) off the shaft. The rubber in
the seal head may be partially adhered to the shaft. In removing seat and o-ring (21) be very careful
in prying it out of seat holder (18). Seat holder is permanently pressed into the bracket. DO NOT
REMOVE.
NOTE: THE MECHANICAL SEAL IS A PRECISION PRODUCT AND MUST BE TREATED AS SUCH.
DURING REPLACEMENT, CARE MUST BE TAKEN TO AVOID DROPPING ANY PART OF THE SEAL,
TAKE PARTICULAR CARE NOT TO SCRATCH THE LAPPED FACES ON THE WASHER OR THE
SEALING SEAT. DO NOT PUT A SEAL BACK INTO SERVICE UNTIL THE SEALING FACES OF THE
WASHER AND SEAT HAVE BEEN LAPPED OR REPLACED.
6.
The interior surface of the seat holder (18) should be cleaned of all residue. Coat new seat and o-ring
with soap and press into seat holder (18). Be sure seat and o-ring are seated firmly and
perpendicular to pump shaft.
7. Install new rotary seal (22) and insert key (14) in shaft keyway.
8. Slide impeller (37) onto shaft and replace acorn nut (3).
9. Replace new casing gasket (27) on bracket (15). Slide entire motor-bracket into casing (28). With
assembly properly positioned, in casing, replace 8-bolts (30). Reattach 4 support bracket bolts to
base.
10. Reconnect all electrical connections and open suction and discharge valves.
Motor Replacement
1. Disconnect wiring.
2. Loosen coupling at impeller shaft (63).
3. Remove 4-motor/bracket bolts (30B).
4. Remove 4-bolts (43), 4-washers (44), and 4-nuts (47) from motor support bracket (38).
5. Pull motor from bracket.
6. Remove coupling and place on new motor shaft.
7. Replace new motor in bracket and re-install 4-bolts (30B).
8. Replace 4-bolts (43), 4-washers (44), and 4-nuts (47) to motor support bracket (38).
9. Fasten coupling to impeller shaft.
10. Align coupling and tighten.
11. Check alignment after assembly.
12. Connect wiring to motor.
Cartridge Assembly Replacement
1. Disconnect wiring to motor.
2. Close shut-off valves on either side of pump casing, or if there are no valves, drain system to below
pump casing.
3. Loosen coupling from impeller shaft.
4. Remove motor by removing 4-bracket bolts (30B), 4-motor support bolts (43), 4-washers (44), and
4-nuts (47).
5. Remove 8-bolts holding bracket to casing and remove old bracket assembly. Clean old gasket (27)
from casing flange. New gasket is included with new cartridge unit.
6. Remove impeller nut (35), impeller (37), and shaft key (14) from old bracket assembly using 9/16"
socket wrench.
7. Remove rotary seal assembly (22).
8. Remove stationary seal (21) by inserting screwdriver at outer edge of seal and prying outward.
DO NOT REMOVE PRESSING-IN BRASS SEAL CUP.
9. Remove 3-cartridge bolts (30A) that fasten cartridge unit within bracket. Remove cartridge and
replace with new unit.
10. Coat new stationary seal assembly (21) with soap and press into brass seal cup (18) by hand. Be
sure seal is seated firmly and perpendicular to pump shaft.
11. Install new rotary seal assembly (22) and insert new key (14) in shaft keyway.
12. Install impeller (37) and impeller nut (35).