Bell & Gossett DN0129D Series CMU - Manual (Page 5)

The mechanical seal can be r eplaced without pulling the unit or
without removing motor wiring. Follow these instructions.
1. Close inlet gate valve and operate pump momentarily to
remove as much liquid as possible from pump. Close dis-
charge line gate valve.
2. Shut-off and lock out power.
3. Make sure unit is cool enough that pump can be handled safely.
4. Disconnect motor leads and conduit. If flexible conduit is used,
wiring may not need to be disconnected.
5. Remove motor from motor support (half of the flexible coupling
will come away with the motor) and set aside.
6. Remove remaining part of flexible coupling from pump.
7. Remove grease coverplate from bearing support.
8. Remove the snap-ring from above the bearing.
9. Remove the four screws that hold the bearing support in place.
10. Insert two screws, 3 / 8 x 16 at least 1 1 / 2 " long, into the tapped
holes in the flange around the bottom of the bearing support,
and “jack up” the bearing support by turning both screws
evenly, or by alternating half-turns.
11. With the bearing support freed, remove the stationary part of
the seal, the slinger, and the bearing from the bearing support.
Remove the old gasket, and place the new gasket on the motor
support.
12. Check condition of the bearing, and re-grease if necessary,
with Chevron SRI #2 grease.
13. Remove rotating part of seal from shaft, leaving collar in place
on shaft.
14. Place rotating part of new seal on shaft; soap both the shaft
and the “rubber” portion of seal.
15. Clean the recess in the bearing support where the stationary
part of the seal fits.
16. Soap the “rubber” portion of the stationary part of the seal and
press it and the ceramic seat into the cavity in the bearing sup-
port, being certain both parts are bottomed evenly.
17. Lower the bearing support and its part of the seal over the shaft
very carefully; press the slinger over the end of the shaft and as
far down the shaft as it will go.
18. While the bearing support is still loose, re-install the bearing in
its cavity by pressing the bearing onto the end of the shaft as
far as possible by hand, centering the outer race in the top of
the cavity; be careful that the bottom of the bearing support is
aligned properly in the rabbet of the motor support.
Do not for ce the bearing as this may damage the pump.
19. Use a short length of tube or pipe that will clear the shoulder
on the shaft and still fit on to the bearing’s inner race; a length
of
5 / 16 " threaded rod; a large washer; and a nut. Thread the rod
into the tapped hole in the end of the shaft and place the tube
or pipe over the inner race of the bearing. Add the washer over
the end of the tube or pipe, and turn the nut down the rod until
finger-tight. Check the alignment of the bearing in its cavity, the
bearing support in its rabbet in the motor support, and the tube
or pipe on the bearing inner race.
20. Carefully tighten the nut, guiding all parts as required, until the
bearing is bottomed against the shaft shoulder and the bottom
of its cavity.
21. When certain the bearing is in place, remove the nut, washer,
rod, and tube or pipe. Re-install the four screws around the
base of the bearing support.
22. Re-install the snap-ring, and fill the space above the bearing
with shell alvania RL2 grease (or equal).
23. Re-install the grease coverplate.
24. Align the water slinger as well as possible by inserting a narrow
screwdriver or other probe through the drain holes in the bear-
ing support.
25. Re-install the flexible coupling on the shaft using threaded rod
and washer as a driver. Don’t forget the rubber spider.
26. Mount the motor in place, re-connect the motor leads and con-
duit. Check for free rotation.
27. Slowly open inlet valves. See warning.
28. Jog to check motor rotation. See caution.
29. Observe operation thru several cycles.
CAUTION: HOT SURFACE
Surfaces ar e hot when system is in operation. Do not
touch hot receiver, let unit cool before servicing. Failure to
follow these instructions could result in serious injury
or death.
W ARNING: HIGH VOLTAGE
Disconnect and lock out power befor e connecting or
servicing unit. Failure to follow these instructions could result
in serious injury or death.
CAUTION: DO NOT RUN DRY.
SEAL DAMAGE MAY OCCUR.
Inspect pump seal r egularly for leaks. Replace as required.
Failure to follow these instructions could result in serious
injury or property damage.
W ARNING: EXPLOSIBLE
Do not pr essurize receiver. Isolate receiver during leak
test. Do not plug overflow. Do not restrict vent opening to
atmosphere. Open valves slowly. Failure to follow these
instructions could result in serious injury or death.
CAUTION: DO NOT REVERSE
Reverse operation can cause extensive damage to
pumps. Jog the motor to test for direction of rotation. Failure
to follow these instructions could result in serious injury or
death.
SERIES CU AND CMU MECHANICAL SEAL REPLACEMENT
5