22.10.2002
GB
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5. Dismantling and assembly
The GRUNDFOS centrifugal pumps, types CRN 16/CRT 16, are multistage in-line pumps.
If it is necessary to dismantle the pump, either because it is choked or damaged, please follow the instruc-
tions below.
Position numbers, see “Parts list” and section
3. Service tools
.
5.1 Dismantling
Slacken the screws pos. 7a and remove them together with the coupling guards pos. 7. Remove the hexa-
gon socket head screws, pos. 9, the coupling, pos. 8, and the shaft pin, pos. 10.
Slacken and remove the hexagon head screws, pos. 28. The motor is now free and can be lifted off.
Remove the nuts, pos. 36, and the washers, pos. 66a.
CRN 16 S: Remove the nuts, pos. 128, the hexagon socket head screws, pos. 127, and the washers, pos.
129.
Loosen the pump head, pos. 2, with a light blow on the edge. Remove the pump head (with with pump head
cover, pos. 77, stationary shaft seal part and disc spring, pos. 60).
Pull the rotating shaft seal part off the shaft, see section
4. Shaft seals
.
The seal ring must not be exposed to blows or knocks.
CRN 16 S: Remove the hexagon socket head screws, pos. 134, and the washers, pos. 135.
Remove the outer sleeve, pos. 55, and the top chamber, pos. 3.
Loosen the chamber stack with a light blow of a rubber mallet and lift it out of the inlet part, pos. 44.
CRT 16: Remove the split pin, pos. 67.a.
Hold the shaft by means of a screwdriver inserted in the shaft pin hole while the nut, pos. 67, is slackened.
Remove the nut, the washer, pos. 66 (not included in CRT), and the spacing pipe, pos. 64c.
Place the shaft holder, pos. A, in a vice and tighten it. Place the chamber stack in the shaft holder with the
threaded shaft end pointing upwards.
Make sure that the chamber is positioned in the recess of the shaft holder, pos. A, and that the shaft can
pass freely through and underneath the shaft holder.
Screw the punch for dismantling, pos. B, home on the threaded shaft end.
The first chamber to be removed is always a chamber with bearing ring, pos. 4a. See also section
6. Order
of assembly for chambers and impellers
.
Drive the punch down through the impeller hub by means of a hammer. Remove the free parts from the
shaft: Impeller, spacing pipe, chamber, bearing ring and spacing pipe. Repeat the procedure until the shaft
passes through the shaft holder, pos. A.
Take care not to damage the shaft when it is driven free of the last impeller and the spacer for shaft seal,
pos. 61.
Remove the punch, pos. B, from the threaded shaft end.
If the stop ring, pos. 62, is damaged, push it out of the recess and pull it free of the spline (towards the
threaded shaft end).
Pump head
Press the stationary shaft seal part out of the pump head by means of a nylon punch or a similar tool, see
section
4. Shaft seals
, and remove the gasket, pos. 37.
The stationary seal ring must not be exposed to blows or knocks.
Remove the air vent screw, pos. 18, (right-hand thread) with O-ring, pos. 100.
Loosen the pump head cover complete, pos. 77, from the pump head by knocking the socket, in which the
air vent screw was fitted, downwards by means of a rubber mallet.
