
12 Instruction manual CTM mag drive pumps
IOM manual Tapflo PE & PTFE series pumps 13
3. MAINTENANCE
Table A, identification of the problem
Problem Possible cause
Pump does not perform head required 1,2,3,4,9,10,11,12,14,15,17,18,19,24,29,32
Insufficient flow rate 2,3,4,5,6,7,8,9,10,11,12,14,15,17,18,29,32
Low delivery pressure 9,12,14,15,17,18,21,29
Pump unmprimes after startup 2,3,4,9,10
Leaks from pump 14,19,21,23,24,25,27,33
Abnormal power absorption 13,16,17,18,21,23,24,25,26,28,30
Vibrations and unnatural noises 2,3,6,7,9,10,11,16,19,21,24,26,27,28,29,30,31,32
Bushing life too short 27,28,29,33
The pump overheats 1,6,9,13,19,20,24,26,28
Table B, possible causes of the problem
1 The Pump is not primed
2 Suction height too high
3 Suction piping or pump not completely full of liquid
4 Suction piping with air pockets
5 Insufficient suction pressure
6 Vapour pressure is too high
7 Suction piping has too high friction losses
8 Insufficient suction head
9 Too much air or gas in the pumped liquid
10 Suction piping not sealed
11 Bottom valve not sealed or clogged
12 Low rotation speed
13 High rotation speed
14 Wrong direction of rotation
15 The plant head is higher than the pump
16 The plant head is lower than the pump
17 Liquid with density differing from the expected one
18 Liquid with viscosity differing from the expected one
19 Operation without liquid -dry running-
20 Operating flow rate too low
21 Operating flowrate too high -pump cavitates-
22 Material not suitable for pumped liquid
23 Pumped liquid with suspended solid substances
24 Liquid temperature too high
25 Liquid temperature too low
26 Insufficient pressure or bushes flushing -lubrication-
27 Shaft is not straight
28 Static and rotating parts rubbing
29 Damaged impeller
30 Inner bushes worn or damaged
31 Rotating unit out of balance
32 Magnetic coupling damaged or insufficient
33 Wrong assembly or with dirt
3.2.1 Trouble shooting tables
3. MAINTENANCE
3.3 Assembly and disassembly
The assembly and disassembly should only be performed by qualified personnel.
Each operation carried out on the machine must always be carried out once all the electrical contacts
have been disconnected. The pump-motor unit must be placed in a position where it cannot be started
unintentionally.
Before servicing in any way the parts in contact with the pumped liquid, make sure that the pump has
been fully emptied and washed. When draining the liquid, make sure that there is no danger for people
or the environment.
3.3.1 Disassembly of the pump
For dismantling the pump proceed as follows (see drawing below):
Dismantle the pump casing (13) from the lantern (11), by loosening screws (141) washers (142) and nuts
(143).
Pull out the static bushing (1521) from the casing.
For CTM 20-7: remove the impeller magnet assembly (90) extract rotating bushing (1511) and rear bushing
(1512) and the O-ring (1812).
For CTM 25-8 and 25-10: remove the impeller magnet assembly, extract rotating bushings (1511) and
(1512) and the O-rings (1811) and (1812).
The static and rotating bushes are usually made from very fragile sintered material and therefore has to
be handled with extreme care.
Remove the casing O-ring (18) from the isolation shell (12).
Extract the isolation shell (12) from the lantern (11).
Loosen the lock screws (161).
Remove the external magnet assembly (16) from the lantern (11) loosening the screws (111).
!
STOP
CTM 25-8
CTM 25-10
CTM 20-7