Johnson Pump SPX Flow CombiLineBloc Instruction Manual page 34

32
Table 8: Possible causes of pump failures.
Possible causes
1 Pump or suction pipe is not sufficiently filled or de-aerated
2 Gas or air coming from the liquid
3 Air lock in the suction pipe
4 Air leak in the suction pipe
8 The manometric suction head is too high
9 Suction pipe or suction strainer is blocked
10 Insufficient immersion of foot valve or suction pipe during operation of the pump
11 NPSH available too low
12 Speed too high
13 Speed too low
14 Wrong sense of rotation
15 Pump does not operate at the right duty point
16 Liquid density differs from the calculated liquid density
17 Liquid viscosity differs from the calculated liquid viscosity
18 Pump operates when the liquid flow is too low
19 Wrong pump selection
20 Obstruction in impeller or pump casing
21 Obstruction in the piping
22 Wrong installation of the pump unit
24 Rotating part running out of true
25 Imbalance in rotating parts (for instance: impeller or stub shaft)
26 Stub shaft is running out of true
27 Bearings faulty or worn out
29 Damaged impeller
30 Seal faces of the mechanical seal are worn out or damaged
32 Bad mounting of the mechanical seal
33 Mechanical seal not suitable for the pumped liquid or operation circumstances
36 Flushing liquid to the mechanical seal is polluted
37 Axial retaining of impeller or stub shaft is defective
40 Wrong or polluted lubricant
42 Too high axial force because of worn dorsal blades or excessive inlet pressure
Problem solving
CLB/EN (1901) 6.6